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Net-zero cultural urbanism: the implementation of traditional and cultural net-zero urban housing design in Lagos

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Net-zero cultural urbanism: the implementation of traditional and cultural net-zero urban housing design in Lagos

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Content Net-Zero Cultural Urbanism
The Implementation of Traditional and Cultural Net-Zero Urban Housing Design in Lagos
by
Chioma B. U. Okonkwo
A Thesis Presented to the
FACULTY OF THE USC SCHOOL OF ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF BUILDING SCIENCE
December 2024
Copyright 2024 Chioma Okonkwo

ii
ACKNOWLEDGEMENTS
Committee chair:
Professor Kyle Konis, Ph.D., AIA
USC, School of Architecture
Email: kkonis@usc.edu
Committee Member #2:
Professor Anthony Brower, FAIA, LEED Fellow
USC, School of Architecture
Populous
Email: anthony.brower@usc.edu
Committee Member #3:
Professor Karen M. Kensek, DPACSA
USC, School of Architecture
Email: kensek@usc.edu

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TABLE OF CONTENTS
Acknowledgements................................................................................................................... ii
List of Figures.......................................................................................................................... vi
Abstract.................................................................................................................................... ix
Chapter One: Introduction .........................................................................................................1
1.1 What is Urban Housing......................................................................................2
1.2 Types of Urban Housing Typologies.................................................................4
1.3 The Importance of Urban Housing ....................................................................7
1.4 The History of Urban Housing ..........................................................................8
1.5 Internatinal Implicatios on Housing.................................................................10
1.5.1 Population Concerns................................................................................11
1.5.2 Nigeria......................................................................................................13
1.5.3 Lagos........................................................................................................22
1.6 Housing Zero Net Energy ................................................................................26
1.6.1 Tropical Design........................................................................................29
1.6.2 Use of Psychrometric Chart Strategies....................................................32
1.6.3 The 2000-Watt Society ............................................................................36
1.7 Approach of Determining Energy Consumption .............................................38
1.8 Summary..........................................................................................................41
Chapter Two: Background Research .......................................................................................43
2.1 Urban Housing Successes in Developing Countries........................................44
Lynedoch Eco Village in Stellenbosch ........................................................44
Mahindra World City in Chennai, India .....................................................46
The Sankofa House in Ghana .....................................................................51
2.1.2 Systems and Methods that Work .............................................................53
2.1.3 Habitat for Humanity Guide ....................................................................56
2.2 Existing Urban Housing Typologies in Nigeria...............................................60
2.3 Existing Characteristics and Design Feautures in Nigerian Homes ................63
2.4 Software ...........................................................................................................67
2.4.1 Rhinoceros 3D (Robert McNeel & Associates).......................................67
2.4.1.2 Grasshopper - Ladybug & Honeybee (Ladybug Tools LLC)..........68
2.4.2 Cove.Tool (Patter r+d).............................................................................69
2.4.3 Climate Consultant (Energy Design Tools at UCLA).............................70
2.5 Recent Energy Simulation Research in Nigeria...............................................71
2.6 Summary..........................................................................................................73
Chapter Three: Methodology...................................................................................................74
3.1 Site and Climate Analysis................................................................................75

iv
3.1.1 Climate Data ............................................................................................75
3.1.2 Zone Measures.........................................................................................77
3.2 Parameter Hunt ................................................................................................77
3.3 Existing Case Study .........................................................................................79
3.3.1 Modeling of Existing Case Study ............................................................80
3.3.2 Cove Tool Analysis.................................................................................81
3.4 New Case Study...............................................................................................82
3.4.1 Design Modification and Simulation.......................................................82
3.5 Summary..........................................................................................................83
Chapter Four: Simulations. ......................................................................................................85
4.0 Analysis of Existing Case Study......................................................................86
4.1 Modeling of Existing Case Study ....................................................................88
4.1.1 Rhino 3D Simulated Model .....................................................................92
4.2 Energy Usage of Structure .............................................................................100
4.2.1 Energy Usage of Baseline Model ..........................................................102
4.3 Energy Conservation Methods.......................................................................109
4.4 Building Orientation and Form......................................................................111
4.4.1 Reposition of Building - Maximize Natural Daylight ...........................113
4.4.2 Reposition of Building - Minimize Heat Gain.......................................116
4.4.3 Form.......................................................................................................117
Scenario 1: Adding Stories to the Building ..............................................118
Scenario 2: Splitting a Building into Two Separate Buildings..................119
Scenario 3: Changing the Building Shape .................................................120
4.5 Passive Solar Design......................................................................................120
4.5.1 Window Sizing on Warm Sides (East) ..................................................121
4.5.2 L-Shaped Windows................................................................................123
4.5.3 Shading Devices.....................................................................................125
4.5.4 Overhangs..............................................................................................129
4.6 High-Performance Building Envelope...........................................................132
4.6.1 Material Selection ..................................................................................133
4.6.1a Sustainable Materials .....................................................................133
4.6.1b Thermal Mass Materials ................................................................134
4.6.2 Modified Insulation................................................................................136
4.6.3 High-Performance Fenestration .............................................................137
4.7 Summary........................................................................................................140
Chapter Five: Energy Conservation Method Categories.......................................................141
5.0 Overview of Chapter 4 Results......................................................................141
5.1 Grouping ........................................................................................................143

v
5.2 Methodology for Studying Groups Using Cove.Tool....................................145
5.3 Parameters Considered for Grouping.............................................................148
5.4 Group 1: Building Design, Orientation, and Form ........................................150
5.4.1 Impact of Design on Energy Efficiency and Thermal Performance......151
5.5 Group 2: Building Envelope and Materials...................................................154
5.5.1 Performance Results ..............................................................................155
5.6 Group 3: Fenestration, Window Placement, and Operable Windows...........157
5.7 Grouped Simulations in Comparison to ZNE Targets...................................163
5.7.1 Comparison to Local Industry Standards...............................................163
5.7.2 Comparison to Local Industry Standards...............................................164
5.8 Summary........................................................................................................165
Chapter Six: Conclusions and Future Works.........................................................................166
6.1 Final Discussion.............................................................................................166
6.1.1 Present Concerns....................................................................................166
6.1.2 Adaption to Local Climate and Culture .................................................168
6.1.3 Single ECMs..........................................................................................170
6.1.4 Grouped ECMs ......................................................................................173
6.2 Future Work...................................................................................................174
6.2.1 Future Work Topics...............................................................................174
6.3 Summary........................................................................................................178
References..............................................................................................................................180
Appendix................................................................................................................................188

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LIST OF FIGURES
Figures
1.1: Number of people living in urban versus rural areas around the world………………...13
1.2: Nigeria’s population density in comparison to Africa and the United States…………...14
1.3: Nigeria’s population density in comparison to the rest of the world……………………15
1.4 Nigeria’s energy use per capita…………………………………………………………..16
1.5: Los Angeles’ electricity rates in comparison to the national average…………………..17
1.6: United States’ electricity consumption by sector……………………………………….17
1.7: Nigeria’s electricity consumption by sector…………………………………………….19
1.8: Lagos’ hourly dry bulb temperature and relative humidity……………………………..24
1.9: Lagos’ dew point temperature throughout the year……………………………………..25
1.10: Lagos’ total sky coverage throughout the year………………………………………...26
1.11: Nigeria’s energy consumption per capita in comparison to the United States………...28
1.12: Adaptive comfort chart………………………………………………………………...30
1.13: Psychrometic chart results for Lagos State…………………………………………….32
1.14: Cove.Tool psychrometric chart results showing indoor comfort levels without
design strategies………...……………………………………………………………...33
1.15: Climate Consultant psychrometric chart results showing indoor comfort levels
without design strategies………...…………………………………………………......34
1.16: Climate Consultant psychrometric chart results showing design strategies to
achieve indoor comfort……...…………...…………………………………………….36
1.17: Graph comparing the United States’ average energy use per person and the goal of
the 2000-Watt Society “One Target for All”……………...………………………..….37
2.1: SIDAREC Community Center in Nairobi, Kenya………………………………………46
2.2: Chennai, India’s Mahindra World City…………………………………………………47
2.3: Relative temperature and humidity of Chennai, India’s Mahindra World City………...49
2.4: Psychrometric chart of Chennai, India and its respective impact of design strategies….50
2.5: Sankofa House passive design diagram…………………………………………………52
2.6: The rehabilitated Sankofa House in Ghana’s Ashanti Kingdom………………………..53
2.7: Interview Questions for Nigerian Residents…………………………………………….66
3.1: Workflow methodology diagram………………………………………………………..75
4.1: Homes with and without Overhangs or Balconies in Nigeria…………………………..88
4.2: Measurements of Existing Building’s Individual Spaces……………………………….89
4.3: Ground-Level Floor Plan of Existing Structure…………………………………………90
4.4: Floor Plan of 2nd and 3rd Stories Existing Structure…………………………………...90
4.5: Air Conditioning vs. Cross Ventilation usage in Nigeria……………………………….92
4.6: Existing Model Initial Envelope Values………………………………………………...94

vii
4.7: Existing Model Initial Usage and Schedule Initial Values……………………………...97
4.8: 3D Rhinoceros Model of Existing Building…………………………………………….98
4.9: Building System Initial Building System Set Points…………………………………..100
4.10: Monthly Energy Usage of Actual Existing Structure………………………………...102
4.11: Cove.Tool Grasshopper Script for Simulated Model………………………………...104
4.12: Cove.Tool Address Input and Energy Code for Simulated Model…………………...104
4.13: Solar Energy General Initial Inputs…………………………………………………..105
4.14: Energy Model of Initial Building with BREPS………………………………………106
4.15: EUI Breakdown of Existing Baseline Model………………………………………...108
4.16: Energy Usage Percentage Catergories of Existing Simulated Model………………..109
4.17: Energy Conservation Methods and Their Final Outcomes…………………………...111
4.18: Proposed EUI after Maximizing Natural Daylight…………………………………...115
4.19: Proposed EUI with East-West Window Sizing………………………………………122
4.20: Location of L-Shaped Windows and Energy Modeling BREPS……………………..125
4.21: Proposed EUI after L-Shaped Windows……………………………………………...125
4.22: New U-Values after Shading Devices are added to Simulated Model……………….126
4.23: Simulated Model with Addition of Shading Devices………………………………...128
4.24: Proposed EUI with Shading Devices…………………………………………………129
4.25: Energy Model of Existing Building with Use of Overhangs…………………………130
4.26: Proposed EUI with Overhangs……………………………………………………….131
4.27: Proposed EUI with Modified Insulation……………………………………………...133
4.28: Proposed EUI with New Materials Selection………………………………………...135
4.29: Proposed U-Values after Simulations………………………………………………...139
4:30: Proposed EUI Outcomes after Simulating ECMs……………………………..……..139
5.1: Grouped Energy Conservation Methods……………………………………………….150
5.2: Case Study Rotated 90 degrees from Existing…………………………………………151
5.3: Overhang modeled with shading devices……………………………………………...152
5.4: Combined Shading Device Locations………………………………………………….153
5.5: Group 1 EUI Baseline Energy…………………………………………………………153
5.6: Group 1 EUI Baseline Breakdown for Proposed Model………………………………154
5.7: Group 2 EUI Baseline Energy…………………………………………………………157
5.8: Group 2 EUI Baseline Breakdown for Proposed Model………………………………157
5.9: Curtain Wall and Fenestration Placements………………………………………….…159
5.10: Group 3 Fenestration and Window Operability Inputs……………………………….160
5.11: Group 3 Custom Curtain Wall Fenestration Inputs…………………………………..161
5.12: Group 3 EUI Baseline Energy………………………………………………………..162
5.13: Group 3 EUI Baseline Breakdown for Proposed Model……………………………..162
5.14: Proposed EUI Outcomes with Grouped ECMs………………………………………164

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5.15: Proposed EUI Outcomes with Grouped ECMs in Comparisons……………………..165
6.1 Methodology Diagram………………………………………………………………….169
6.2: Apartment Unit Program Dimensions…………………………………………………170
6.3: Monthly Energy Usage of Actual Existing Structure………………………………….172
6.4: Energy Conservation Methods and Their Final Outcomes…………………………….172
6.5: Grouped Energy Conservation Methods and Their Final Outcomes…………………..174

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ABSTRACT
Urban housing presents a significant challenge in fast-growing cities like
Lagos, Nigeria. The inflow of people to the city often worsens housing issues, leading
to problems with affordability and environmental stress. This situation is common in
many cities worldwide, showing the urgent need for new solutions that address local
housing requirements and prioritize environmental sustainability. As a result of this
pressing issue, in informal settlements and substandard living conditions have become
the norm. Net-zero housing has emerged to be a promising solution that aligns with the
worl's shift towards sustainable development. In Lagos, net-zero housing has the
potential to bring influential transformation. By incorporating renewable energy
sources such as solar power, passive strategies, and energy-saving technologies, netzero housing can reduce overall energy usage and carbon emissions and provide
affordable, eco-friendly living spaces that complement the city's dynamic atmosphere.
Because renewables are often insufficient in towns like Lagos, passive design strategies
can be seen as a more beneficial solution. This approach directly tackles the energy
challenges faced by urban areas like Lagos, where power supply is often unreliable and
fluctuates daily. Net-zero housing is being implemented globally to combat climate
change. Because Lagos is situated on the coast of southwestern Nigeria, it experiences
a significant risk due to climate change effects, such as severe weather conditions and
electricity generation. The city also experiences a hot, tropical climate for most of the
year. Net-zero housing helps mitigate these effects by promoting sustainable
construction practices and lowering greenhouse gas emissions. By embracing net-zero
housing strategies, Lagos can lead the way towards a sustainable urban future, serving

x
as a model for other cities worldwide have similar issues. This not only addresses the
immediate housing needs of the city's residents but also makes a significant
contribution to environmental sustainability.
A case study determined that a typical multi-family home in Lagos, Nigeria,
could be modified using passive design strategies. After simulating its outcomes, at
least forty percent of energy will be saved, bringing the home closer to achieving netzero energy and making it more comfortable for those who occupy it.
Keywords: Zero Net Energy (ZNE) design, passive design, urban housing,
energy efficiency, thermal comfort, indoor cooling, Lagos

1
Chapter One: Introduction
1.0 Introduction
Over the past two decades, Nigeria's rate of urban expansion has been on the
rise. As a result of this, the segments of the country’s population that reside in urban
areas have increased exponentially in recent years (Akinyemi, 2023). With the rapid
urge to transform Nigeria’s economic and political state and the diaspora moving back
to the country, this growth has also led to several issues when it comes to housing,
specifically relating to energy efficiency. The sprawl, or expansion of an urban area
into the adjoining countryside, has contributed to a decline in overall affordable and
adequate housing and has created problems of overcrowding and larger unhoused
populations.
In Africa, the meaning of sustainability is different as the continent often
struggles with more complex environmental challenges and the exploitation of its
natural resources and materials. Of these environmental challenges, the country’s
energy supply crisis remains dominant due to its lack of adequate infrastructure, limited
investment in the power sector, and government challenges that limit the management
of the power system. These pose a huge issue in cities with dense populations and
unreliable power supply, like Lagos. Net-zero energy design, a design method that
incorporates the use of passive design strategies in a building to produce more energy

2
than it consumes (HMC Architects, 2020), is a promising solution to this problem as
its implementation reduces the city’s footprint through means of energy reduction.
Nigeria is a fresh playing field to incorporate the use of such design strategies and local
resources to aid in energy-efficient design patterns. This chapter is about urban
housing, its international implications, and housing net zero.
1.1 What is Urban Housing
This section is about urban housing, its importance, its history in the United
States, and its implications in developing countries. National Geographic defines urban
housing as living, or residential living arrangements, in urban areas such as cities and
local towns (National Geographic website). These urban areas are usually densely
populated and made up of many buildings, infrastructure, and businesses. It houses a
large variety of housing typologies that accommodate the cities’ residents. Urban
housing typically is comprised of a wide variety of buildings like skyscrapers, highrise apartments, duplexes, townhouses, condominium buildings, and in some cases,
single-family homes that have city-like neighbors have surrounded themselves over the
past few years.
The implementation of residential areas is primarily encouraged by limited
land, which serves as a driver and occurs in populous areas. As a result, building
upwards can become the solution to providing the maximum amount of housing due to
its smaller footprint or area that is used by the site’s building structure. Urban housing

3
can almost always be a depiction of the traditional identity that makes up the specific
city.
Over 91% of Lagos’ population live in the city making its metropolitan
population density about 24,000 people per square kilometer. The occupancy ratio is
about 9 people per room with 72.5% of households occupying a one-room apartment
(Lagos State Ministry of Housing, 2010, cited in Alufohai, 2013). In Los Angeles,
California the population density is about 3,136 per square kilometer as its total
population is about 3.8 million people (McAllister, 2024). Nigeria’s second most
populous city, Kano, has a population density of 20,000 people per square kilometer
(Lagos State Ministry of Housing, 2010, cited in Alufohai, 2013). The differences in
population densities emphasize the differences in urban living globally. While Kano’s
lower density shows that there is more space per person, it also indicates that there
could be fewer urban resources than Lagos’ higher density. This is why the term urban
can differ depending on the location that a person is in.
In Lagos, urban housing is defined by real estate activities of a different nature
(Oyalowo, 2022). This means that Lagos takes into account different aspects of real
estate that impact city living, including market trends, housing regulations, and the
building process as a whole. Urban housing in Lagos includes a mix of residential
development. rentals, and informal housing. Here, these components often come as a
result of population density and economic circumstances that impact how housing is
developed, prices, and maintained. Because of this, urban housing in Lagos goes far

4
beyond providing a roof over one’s head; it relates directly to navigating the
relationship between legal, economic, and social factors to create urban living spaces.
In the United States and other parts of the world, urban housing diversifies the
city architecturally as it houses different neighborhoods, each accompanied by their
special qualities. However, regardless of the location that a person is in, it is safe to say
that urban housing plays a key role in bringing about a sense of belonging within a
community and shared residential social experiences.
1.2 Types of Urban Housing Typologies
Urban housing is accompanied by a wide variety of typologies. Each of these
different typologies has many sides that complement the feeling of living in the city.
This is beneficial because it is essential that urban housing serves a diverse array of
preferences and considers all lifestyles. Of these typologies are single-family detached
homes, single-family attached homes, multi-family attached homes, medium-density
developments that typically consist of sixteen to twenty units, and large-density
developments that typically consist of around one hundred units (Northridge, Ramirez,
Stingone, and Claudio, 2010).

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The most dominant form of urban housing is apartment buildings, multi-story
structures that are made up of residential units. Some apartment buildings also include
various amenities available to all occupants like gyms, pools, and dog parks. The
majority of cities are home to high-rise apartment complexes that optimize land use
and cater to the larger amounts of people that reside there. Apartments are typically
single-floor, but may also include duplex formats of two stories or more, and can also
include different layouts depending on the usage of space and occupants’ needs.
Townhomes are another common example of housing typologies within urban
areas. They are multi-family, multi-story housing projects made up of residential units
that share a “party” wall on either side. They are usually constructed in rows and
accompanied by street landscapes to provide the sense of a smaller city, or
neighborhood, within a city. Each townhome offers its own front lawn and/or backyard.
Their layout offers a tall, narrow, more compact approach.
Similar to townhomes, condominium buildings, or condos, make up a large
number of housing types within urban areas. These fuse separation and common spaces
into one building. Condos typically come with ownership of the residential unit itself
and shared amenities among neighbors and residents (Iacoviello, 1979). They can best
be described as a hybrid between an apartment building and a townhome, but, they are
often privately owned and come with a long-term commitment as opposed to a monthto-month lease.

6
Single-family homes are not as common in urban areas, but when they are
present, they are usually designed to blend in with the scheme of the urban area in
which they reside to complement the neighborhood’s patterns. Urban single-family
homes can easily be classified as “modern” and are usually new developments or
“standouts.” Presently, these new developments typically sit on the same street and
consist of the same number of models repeated throughout the neighborhood. This
means that the existing single-family home does not blend in with its surrounding
neighborhood as the architectural urbanization grew around it.
Mixed-use housing projects merge residential spaces and commercial spaces.
These commercial spaces are usually retail shops, gyms, or office spaces as a program
element that is a part of the same building. By taking this path in development,
individuals who live within these communities can live, work, and play within the same
vicinity for a more comfortable, simple lifestyle.
Lofts are a more scarce urban housing type that often has an open floor plan,
designated area for beds, and exposed building envelopes to contribute to their
industrial designs (Zukin, 1982). The majority of these types are transformed into lofts
from already existing factory buildings or warehouses. Lofts are often favored by those
who want an open, free living space.

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1.3 The Importance of Urban Housing
Urban housing comes with a lot of positive attributes such as its efficient use of
land, access to public services, inclusivity, sustainable features, and innovative design
technologies that accompany its architecture. Its closeness to public services and
businesses, and its locality in the heart of major urban cities, make urban housing that
much more influential. Living in these urban areas provides simple access to nearby
schools, recreational facilities, jobs, retail stores, health centers, safety stations, and
public transit (Pateman, 2011). It is beneficial to have these resources close by in these
dense cities because of convenience concerns, limited travel time, more socialization,
and the positive environmental impact that it promotes while also contributing to the
decrease of individuals’ footprints on ecology. Urban housing attracts populations that
prefer living closer to public centers and transportation (Pateman, 2011). These
individuals may often be willing to choose a house located in more vibrant cities rather
than rural cities.
Urban housing areas with higher populations usually come with limited spacing
options. This provides an opportunity to use land efficiently. It is safe to say that this
is evident in bigger cities like New York City, Shanghai, San Diego, Tokyo, and Los
Angeles. As a result, building upwards becomes a solution, leading to the development
of high-rises and skyscrapers. Building towards the sky provides space for public areas
and parks while avoiding changes of existing and natural landmarks. Urban housing
creates important public amenities. The need for housing in towns provides educational

8
centers, transportation services, health services, and maintenance facilities (Deupi &
Firley, 2023). Urban towns mix cultural identities and influence diversity across the
board. In neighborhoods, the line of different housing types plays a role in the outcome
of architectural design directly, bringing in bright urban views, social experiences, and
a stronger sense of community (Deupi & Firley, 2023). This fosters impactful
community building. The amount of residents inside a building can directly influence
in-person interactions creating a sense of shared community. Urban housing can be
strategically organized to provide sustainable, passive design techniques (Goodchild,
1994). With the use of energy-efficient technologies and sustainable building materials
and practices, an urban city can be deemed impactful to the world.
1.4 The History of Urban Housing
The idea of urban housing was first spelled out by European models of society
and architectural influences. In the past, people who resided in cities lived in homes
that were inspired by the Greco-Roman way of living (Flohr, 2024). When these
residents eventually made their way to the United States to settle, houses were built to
be functional and suitable for their demands. Once cities began to industrialize, these
demands changed drastically as did individual neighborhoods’ needs. Overcrowding
quickly took its course and Tenements would now symbolize poverty-stricken cities or
living irregularities (Mallach, 2018). These are known low-rise apartment buildings,
known for cramped spaces and poor living conditions that emerged in urban centers.

9
This was most evident in urban areas that were rapidly growing at the time such as New
York City and Boston (U.S. History, 2015). These cities quickly became the faces that
would relate to the skyrocketing population increase during the times of the Industrial
Revolution. Later, the emergence of immigration and the increased need for work in
urban regions influenced the further development of urban housing in Georgia, Boston,
and Philadelphia in the late 1900s (U.S. History, 2015). It was during this time that the
United States gradually began to diversify its living arrangements opting for a more
modern and useful approach to providing housing.
Since then, many bills have been established in the United States to directly
address the improvement of housing, its affordability, and its overall living conditions
for the comfort of people. Some of these include the Housing Act of 1949, the Housing
and Urban Development (HUD) Act of 1965, and the Fair Housing Act of 1968. The
Housing Act of 1949 aimed to eliminate slums and provide decent housing for all
Americans by providing loans to cities and encouraging cities to comprise plans for
urban revitalization (Von Hoffman, 2000). The HUD Act of 1965 was established to
address urban housing issues by incorporating programs for urban development and
federal housing. The Fair Housing (FHHA) Act of 1968 prohibits discrimination
concerning the sale, rental, and financing of housing based on race, religion, national
origin, sex, disability status, and family status (U.S. Department of Housing and Urban
Development). More presently, cities all over the world have aimed to adopt these
urban housing models and incorporate them into their respective systems of housing.

10
1.5 International Implications on Housing
Housing all over the world faces challenges due to economic factors. While
countries grapple with providing for their homeless populations, they also gamble with
the repercussions that could occur outside of their countries. The task of providing
housing that is both affordable and adequate for growing communities is at the center
of this affair. Affordable housing is housing in which the occupant is paying no more
than 30 percent of gross income for income costs, including utilities (Davis, 1995).
Housing is deemed adequate if it meets the minimum structural, heating, ventilation,
sanitary, occupancy, and maintenance standards compatible with applicable building
and housing codes (Watermeyer & Milford, 2003). The United Nations Committee on
Economic, Social, and Cultural Rights recognizes adequate housing as a human right.
It should be seen as a right to live somewhere in security, peace, and dignity (Wilson,
2020). From a socioeconomic standpoint, it is safe to say that the condition of the
housing market directly affects social and economic development on a larger scale. The
2008 housing market crash in the United States had a global effect, leading to a
significant decline in economies worldwide (Duca, Muellbauer, & Murphy, 2010).
Mortgages played a major role in this downfall as people could no longer afford their
homes, affecting both individuals and the banks involved in mortgage payments
(Bianco, 2008). Because the world’s financial resources are intertwined with one
another, the unreliability of the U.S. housing market immediately caused a ripple when
it came to international affairs. Since then, the rising prices of land have posed a

11
significant threat to the future of housing, given the current state of housing demands
(Investopia, 2023).
The global homelessness crisis, caused by the lack of affordable housing, has
further expanded the divide between communities, making them seem insignificant.
The main reason behind this housing crisis is the sudden relocation of populations due
to socioeconomic inequalities and disagreements. As a result, there is a shortage of
resources for the surge of unhoused people and immigrants in their new countries
(Hasan, Al Mahmud, Farabi, Akter, & Johora). This issue not only affects political
relationships between countries but also raises concerns about environmental
sustainability in the construction process. Building and maintaining housing contribute
to carbon emissions and energy consumption. Because of this, there is a growing
emphasis on sustainable practices such as net-zero building design and energy
efficiency. Despite the progress, population concerns remain the primary challenge in
achieving affordable and adequate housing, impacting international implications and
the benefits of urban sprawl (Nechyba & Walsh, 2002).
1.5.1 Population Concerns
In developing countries, the most noticeable change is the continuous transition
of individuals to city living known as urbanization. This is due to increased financial
opportunities, better healthcare services, finer education, and improved living standards

12
(Cattaneo, Adukia, Brown, Christiaensen, Evans, Haakenstad, & Weiss, 2022). As a
result, population growth is at an all-time high and urbanization is expanding rapidly
(Cattaneo, Adukia, Brown, Christiaensen, Evans, Haakenstad, & Weiss, 2022). While
this is an invigorating experience for some parts of the world, it can be overwhelming
for others. In developing countries, where economic growth is frequently at a standstill,
accommodating population growth becomes difficult. As more people find themselves
in these areas, the demand for housing increases significantly. This rapid growth rate
often outweighs the ability to provide urban planning and adequate housing (Ellickson,
1977). While some countries believe that housing is a basic human right, others are
torn between achieving it. People are then forced to settle for whatever living condition
is attainable.
Population growth can have a detrimental impact on rural areas in developing
countries, which can eventually lead to their decline and neglect (Reardon & Vosti,
1995). This is at often times caused by the lack of infrastructure and limited resources
to support the upkeep of these rural communities. By staying in rural areas, people may
experience more difficulties accessing basic needs daily. The United Nations graph
illustrates the population distribution between urban and rural areas globally,
highlighting their respective growth rates (Figure 1.1).

13
Figure 1.1. Number of people living in urban versus rural areas around the world
(UN Population Division, 2024)
1.5.2 Nigeria
Population concern greatly impacts Africa’s most populous country: Nigeria.
Unlike many other African countries, Nigeria has a larger urban population than rural
(Idowu, 2013). Population density varies significantly across the world. While Algeria
and the Democratic Republic of Congo are the largest African countries in terms of
land area, their population is relatively low due to the spread of people throughout the
country. According to Our World in Data, Africa is the second-most populated
continent in the world, with 1-in-6 people living there. It makes up about 17 percent of
the world’s total population, with approximately 1.3 billion people calling Africa home.

14
Nigeria alone has a population of 195.9 million (Subramanian, Alexio Constantinos,
Nellis, Steele, & Tolani, 2019). The population density in Nigeria, measured by the
number of people per square kilometer, is higher than that of both Africa and the United
States as a whole (Figure 2). This high population density is one of the reasons why
Nigeria’s population density is among the highest globally, compared to other areas.
Figure 1.2. Nigeria’s population density in comparison to Africa and the United States
(UN Population Division, 2024)

15
Figure 1.3. Nigeria’s population density in comparison to the rest of the world
(UN Population Division, 2024)
While its urban housing crisis comes as a result of overpopulation, Nigeria’s
specific issue relates directly to its energy usage and insufficient power supply.
Compared to other countries, Nigeria’s energy consumption is relatively low, which
directly affects the design of housing there. According to the U.S. Energy Information
Administration, Nigeria’s energy use per person was estimated to be 2,548 kWh
(Figure 1.4) (Okosun, 2022). This is significantly lower than the United States’s energy
use per capita of 78,754 kWh (Figure 1.4) (Okosun, 2022).

16
Figure 1.4 Nigeria’s energy use per capita
(Our World in Data, 2024)
In Los Angeles, California residents spend about $209 per month on electricity:
about $2,508 per year (EnergySage) (Buck, Auffhammer, Hamilton, & Sunding, 2016).
This is 5% higher than the national average bill of $2,386 (Figure 1.5). Electricity rates
cost about 24 cents per kilowatt-hour (kWh) (Figure 1.5)Buck, Auffhammer, Hamilton,
& Sunding, 2016. Costs often increase with tiers of higher consumption. The average
person living in LA uses about 858 kWh of electricity per month and 10,296 kWh over
a year (EnergySage). In the summer these values rise as the use of heating and cooling
systems such as A/C are prevalent. The city has a reliable electricity supply that allows
for various home appliances to be on simultaneously without the risk of power outages.

17
California, and many other states, also have harsh building codes that include energyefficient standards.
Figure 1.5. Los Angeles’ electricity rates in comparison to the national average
The U.S. produces about 4,501,876 GWh of electricity per year. It consumes
about 12.871 MWh per capita per year (International Energy Agency). In the United
States, residential and commercial sectors account for the majority of energy
consumption, making up about 39% and 34% respectively (Figure 1.6).
Figure 1.6. United States’ electricity consumption by sector

18
In Lagos, Nigeria residents pay about 26,000 naira monthly, or about 312,000
naira per year. Its energy consumption of 140 kWh per capita is relatively low in
comparison to other countries (almost three times lower than the average for SubSaharan Africa) (EnergySage). In an interview process carried out for twelve months,
it was reported that the interviewee consumed an average of about 294 kWh per month
(about 3,529 kWh annually). Nigeria produces 36,037 GWh of electricity per year, thus
accounting for 0.144 MWh of electricity consumption per capita every year
(International Energy Agency). Nigeria’s residential sector accounts for 59% of
electricity consumption within the country (Figure 1.7). This comes as a result of
irregular power supply causing reliance on alternative energy sources such as
generators. Lagos also has a different standard of living so A/C usage is brought to a
minimum and no heaters are required or necessary due to temperatures. Most of the
homes in the city are older constructions and informal housing settlements. Because of
this, Lagos, and most of Nigeria do not have strict building codes that go hand-in-hand
with energy efficiency.

19
Figure 1.7. Nigeria’s electricity consumption by sector
In many countries, heating and cooling make up a large portion of the energy
usage in homes. While air conditioners and appliances are run electrically, natural
gasses, oils, and coals are still used in developing countries for cooking leading to even
more energy consumption and the spread of emissions into the atmosphere. In Nigeria,
the resident energy use by source comes primarily from biofuels and waste as it makes
up 97% of the total residential consumption (Jekayinfa, Orisaleye, & Pecenka, 2020).
In the United States, 48% of residential energy sources come from electricity and 42%
come from natural gasses (Bilgen, 2014).
Energy usage in Los Angeles is significantly greater than in other parts of the
world including Lagos, Nigeria. This is because Los Angeles is located in the United
States and is a part of a highly developed economy with higher per capita income. This
is also due to Nigeria’s lack of reliability in its electricity grid. It also has a

20
Mediterranean climate with mild winters and hotter summers which causes individuals
to increase their air conditioning usage persistently during the summer. Los Angeles’
infrastructure was designed to support a high-energy-consuming lifestyle. Besides
unstable electricity grids, Lagos has a much lower per capita income resulting in lower
usage levels. It is accompanied by a tropical climate with constant high temperature
and humidity levels. The need for air conditioning is evident in Lagos, however, it is
not popular as it is not as accessible in the region (Ojeh, Balogun, & Okhimamhe,
2016).
While Nigeria’s electricity consumption is seemingly less than most countries
in terms of electricity usage, this is mainly due to the lack of energy resources in the
country. Saving energy is good, but thermal comfort is also crucial for successful urban
housing. In comparison, the United States is doing a poor job and minimizing energy
usage, but a high comfort level is standard of living in the country. Americans consume
more than 100 times the electricity of Nigerians (Omoruyi & Idiata, 2015). This
significant difference is due to limited infrastructure and reliance on energy sources
such as generators, while the United States has near-universal access to the grid (Our
World in Data, 2024). Nigeria has approximately 45% of its population connected to
the grid (Monyei, Adewumi, Obolo, & Sajou, 2018). The growing population in
Nigeria’s urban areas has led to a shortage of hundreds of thousands of housing units.
This, along with the unreliable electricity sources, has greatly impacted the living
quality of Nigeria’s population.

21
In Nigeria, the struggle to provide reliable electricity has led to limitations on
who can enjoy mechanical heating, cooling, and air conditioning. Because of the
nation’s unstable electricity grid, residents have switched to the use of generators,
which increases pollution and emissions (Kabeyi & Olanrewaju, 2022). Residents that
can afford generators include HVAC systems into newer urban developments. This is
primarily because these urban homes can afford mechanical heating and cooling
systems. Those who cannot afford these amenities are faced with the challenge of
staying comfortable in hot temperatures, especially in densely populated areas. The
percentage of households that use HVAC in Nigeria is relatively low compared to other
countries (Adegun, Morakinyo, Akinbobola, Obe, & Olusoga, 2024). The installation
of these systems could also contribute to continuous power outages as the systems
require a higher amount of power than the grid currently offers.
Nigeria’s energy potential in the coming years is expected to be immense and
have a significant impact on the country. By adopting energy-efficient strategies and
renewable sources, Nigeria can tap into its geographical advantages for renewable
energy solutions. To get there, it is important to prioritize the integration of green
energy in future urban housing projects. Alongside increased political changes that
promote this clean energy, both the government and citizens need to recognize the
significance of this transition towards a more sustainable Nigeria. By confronting these
concerns, the problems associated with urban housing can be decreased, and the
country’s lack of unreliable electricity supply gradually becomes less of an obstacle.

22
To reform its urban housing, Nigeria’s transition to energy-efficient practices
must be urgent. Given that Nigeria is one of the most densely populated countries in
Africa, this adoption would serve as a model for other countries that experience the
same types of issues. Implementing energy-efficient practices, like net-zero energy in
urban housing would reduce poverty and boost the community from an environmental
standpoint (Godin, Sapinski, & Dupuis, 2021). Because the majority of Nigeria’s
natural supplies and materials are untouched, the shift toward net zero engery (NZE)
passive design is highly anticipated by many. This shift would allow residents in urban
areas to enhance the thermal comfort of their homes.
1.5.3 Lagos
In West Africa’s most populous city, Lagos, Nigeria, high energy consumption
and population growth contributes to its own challenges. The city’s energy demand is
closely tied to its economic state. Because of this, solutions that relate directly to
sustainable energy are urgently needed. The government of Lagos State has begun
incorporating tactics to eventually shift to cleaner energy (Godin, Sapinski, & Dupuis,
2021). As Lagos continues to grow, this shift is essential to accommodate urban
housing development expansion.

23
Climate
The majority of the African continent is covered by tropical climates that are
known for their high temperatures throughout the year and minimal seasonal changes
(Collins, 2011). Most tropical climates have a lot of rainfall, breaking tropical seasons
into only two seasons: wet or dry seasons. These regions are often relatively high in
humidity and are warm all year round. Unlike many other places in the world, Africa’s
tropical climates don’t experience four distinct seasons. The northern and southern
parts of Africa are dominated by desertlike features. At the heart of the continent, there
are plenty of rainforests and grasslands. Nigeria, Niger, Namibia, and Botswana are
characterized by their woodland and grassland features. Its climate can be classified as
that of a savanna climate that experiences wet and dry seasons with little to no rainfall
occurrences. Typically, the length of the rainfall season decreases as one moves from
its coast to more inward: northern Nigeria or Kano. According to Britannica, the
southern part of Nigeria receives around 120 inches of rainfall annually, while the north
receives no more than 20 inches per year.
Nigeria’s coastal temperatures often remain stagnant throughout the year.
Lagos state is situated on the coast of Benin in southwestern Nigeria. Its topography is
made up of islands and lagoons: Lagos, Iddo, Ikoyi, and Victoria. In Lagos, the outdoor
temperature exceeds the thermal comfort zone as its minimum monthly temperature is
around 69 degrees Fahrenheit. Based on the outputs from the Cove.Tool climate
anaylsis tool and Grasshopper LadyBug tool, the dry bulb temperature in Lagos state

24
depicts the air temperature that excludes radiation and moisture content levels. Because
Lagos is near the Equator, its dry bulb sits high throughout the year, so it is classified
as a tropical climate. Its highest temperatures occur during November and March. This
is because the daytime temperatures range anywhere from 76 degrees Fahrenheit to 88
degrees Fahrenheit (Figure 1.8). Lagos’ outdoor temperature rarely falls below the
thermal comfort zone because it is warmer throughout the year so the thermal comfort
temperature is almost always surpassed. From March to April and October to
November, the monthly temperature is within the normal comfort zone range while
temperatures are warmer from December to February. Its hottest month is typically
March while its coolest month tends to be August (Figure 1.8). Lagos has a low amount
of heating degree days and 1,436 cooling degree days. Therefore, its climate is “cooling
load” dominated. This means that Lagos’ primary concern when it comes to buildings
is being about to remove heat to keep indoor temperatures at a comfortable level.
Figure 1.8. Lagos’ hourly dry bulb temperature and relative humidity (Cove.Tool analysis
report)

25
The dew point temperature of the climate is the temperature at which the water
vapor in the air turns into liquid. This plays a crucial role in Lagos’ humid climate.
Lagos experiences higher dew point levels, meaning that it experiences higher humidity
in the air. This makes the atmosphere feel hotter and more mucky (Figure 1.9). These
high humid levels often impact thermal comfort levels when it comes to living in Lagos,
the amount of energy used to try and cool down, and how long materials last when
building in this climate.
Figure 1.9. Lagos’ dew point temperature throughout the year (Grasshopper LadyBug
Analysis)
Lagos shows the overall sky coverage, which indicates the extent of cloudiness
throughout the year (Figure 1.10). This factor plays a crucial role in shaping the city’s
climate and architectural considerations. When there are more clouds present, it leads
to a natural cooling. Since Lagos doesn’t have a high cloud coverage (Figure 1.10),
utilizing natural light in design is a viable choice. However, preventing buildings from
overheating can be quite challenging. Incorporating natural light during the day not
only enhances the comfort of residents but also encourages energy conservation.

26
Figure 1.10 Lagos’ total sky coverage throughout the year (Grasshopper Ladybug
Analysis)
1.6 Housing Zero Net Energy
Housing Zero Net Energy refers to housing that is designed to consume energy
efficiently and generate an equal amount of energy throughout the year, resulting in a
perfect balance (Deng, Wang, & Dai, 2014). This kind of housing stands out due to its
various notable features, including an adaptable design that can withstand different
climates and the use of renewable energy sources to reduce carbon emissions.
Additionally, the development of these homes pays close attention to the arrangement
and orientation of different elements to aim at bettering sustainability (Deng, Wang, &
Dai, 2014). The urgency of achieving net zero energy housing plays a crucial role in
addressing the challenges posed by climate change.

27
On a global scale, the concept of achieving net zero housing can be defined
differently as it relates to a more lucrative goal of maintaining homes through energy
conservation and reducing their footprints (Maclay, 2014). The challenges become
more critical as limitations begin to take place. In Africa, solar renewable energies are
almost always insufficient and the term ‘sustainable’ has a different meaning as it
cannot depend on heavy technology. Access to resources plays a significant role as
different countries have different capabilities. The use of materials becomes
increasingly important as not every country has access to the same resources. Globally,
climate conditions and environments often differ. The United States offers more
advanced technologies than other parts of the world as well as heavily-enforced
building codes (Sun, Brown, Cox, & Jackson, 2016). This is not the case in many
developing countries including Nigeria, where the focus of net zero housing
development often takes a more traditional approach, incorporating methods of
technology that residents are familiar with and resulting in smaller size, individual
projects (Kabeyi & Olanrewaju, 2022). For Nigerians NetZero housing does not only
mean minimal energy consumption, but also provides comfort to occupants and the
relationship between buildings and residents. Designing for tropical climates is
essential in taking a responsible approach. Nigerian residents have lower energy usage
per capita compared to the United States (Figure 1.11). While the lack of energy
resources is a main contributor, in developing countries, net zero takes a different
approach that cannot rely on just renewable technologies.

28
Figure 1.11. Nigeria’s energy consumption per capita in comparison to the United States
(Our World in Data, 2023)
Passive design strategies offer a promising solution for achieving energy net
zero in Lagos. Similar to Lagos, Los Angeles, California also experiences
overcrowding, homelessness, and housing crises due to its population (Zhu, Burinskiy,
De la Roca, Green, & Boarnet, 2021). Los Angeles is constantly making significant
progress in transitioning to sustainable fuel sources and implementing passive design
strategies, which can serve as models for other parts of California. These characteristics
can be translated and used in other parts of the world. The main differences between
Lagos and Los Angeles lie in their unique cultures, traditions, and the resources and
technology available to them. While Los Angeles’ focus on achieving net zero urban
housing is related specifically to lowered energy consumption and clearing streets,

29
Lagos focuses on the future development of urban housing, how it can provide thermal
comfort to its residents, and its connection to future infrastructure.
1.6.1 Tropical Design
In tropical climates, the architectural design focuses on maximizing natural
ventilation, effective shading, and strategic material selection for high performance in
these areas (Kwag, Adamu, & Krarti, 2019). The tropical design prioritizes its ability
to adapt to climate and durability to take on various weather conditions. It often
incorporates raised buildings and open floor plans to promote air circulation and cross
ventilation. Because tropical design aims to minimize the usage of mechanical
technologies, these design strategies are important for improving thermal comfort
without depending on mechanical technologies. This serves as a more sustainable
approach to addressing climate-related challenges and enhances the functionality of an
individual’s living space. The adaptive comfort chart shows the time of day and time
of year with the greatest human comfort in a specific location (Figure 9).

30
Figure 1.12. Adaptive comfort chart (Cove.Tool analysis report)
Over the past decades, Nigerian homes are usually constructed using concrete
blocks, which means insulation is practically non-existent (Adaji, 2017). Temperatures
are often trapped within the building’s perimeters resulting in overheating. Kitchens
are usually sectioned off into corners of the home in an attempt to mitigate the chances
of heat entering the rest of the building. Bathrooms must be placed on the outskirts of
the residence because it is unsafe to have a room without a window in tropical climates
which can easily be done in American residences. Overhangs and balconies are
common amenities in upper-class developments. These program elements not only
provide additional space for relaxation and comfort but also serve as shading devices

31
to divert heat entering a building (Adaji, 2017). Windows are often larger to allow for
natural light during the day as electricity is unreliable (Adaji, 2017).
While Nigeria already pays much attention to how its buildings are designed,
there is a lot of room for improvement when it comes to providing thermal comfort and
achieving net zero energy (see Figure 1.13). This chart shows the relationship between
dry bulb, humidity ratio, and enthalpy. Each polygon represents a different strategy to
increase comfort. By prioritizing thermal comfort, the reliance on mechanical systems
aids in slashing energy consumption and lead to the overall goal of net-zero energy.
Thermal comfort is linked directly to occupant well-being and productivity, making it
an essential factor for residential design. Focusing on thermal comfort in the context of
passive design addresses both environmental sustainability and considers human
interaction which are being pushed aside in the construction of many Lagos homes
(Adaji, 2017).

32
1.6.2 Use of the Psychrometric Chart to Suggest Strategies
1.13. Psychrometric chart results for Lagos State (Cove.Tool analysis)

33
Figure 1.14. Psychrometric chart results showing indoor comfort levels without design
strategies (Cove.Tool Analysis)
Based on the simulation run in Cove.Tool, Figure 1.14 depicts that a resident’s
thermal comfort in Lagos, Nigeria can be improved by approximately 43%. The Impact
of Design Strategies generated depicts what additional percentage of comfort would be
expected by taking these recommended approaches. Evaporative cooling modifications
would provide an additional 59% of comfort while thermal mass regulation and night
ventilation would provide an additional 71%. Occupant use of fans would give
residents 43% additional comfort. The improvement of the effects of internal heat gain
would provide occupants with an additional 53% of thermal comfort. The modification
of this existing urban housing development can serve as a model for other developing
countries that experience population growth and struggle with reliable energy.

34
Figure 1.15 Psychrometric chart results for Lagos State, Nigeria showing indoor comfort
levels without design strategies (Climate Consultant software)
Then comfort level for Ikeja, Lagos, Nigeria is 0.0% (1h of 8760h) and does
not make buildings comfortable (Figure 1.14). By incorporating passive design
strategies to achieve net zero energy in Lagos, Nigeria, urban housing development can
be improved limiting homelessness and overcrowding. To achieve thermal comfort in
the existing building the following design strategies must be incorporated based on the
psychrometric chart (Figure 11):
- Adaptive comfort ventilation: Cross ventilation, stack ventilation,
operable windows, roof vents, skylights, and doors and passage placement
can all have a positive effect on ventilating a space. In this case, ventilation

35
is required for 6935 hours, contributing 79.2% towards the homes’ existing
thermal comfort.
- Sun shading of windows: Incorporating shading devices (awnings,
overhangs, blinds, or louvers) can greatly improve the comfort level of an
existing urban housing development by about 29.2% (a total comfort
improvement of about 2556 hours in a year).
- Dehumidification only: Because Lagos has high humidity levels,
dehumidification is essential in achieving thermal comfort in the home.
Here, dehumidification would require 3515 hours in a year (pushing the
home closer to achieving comfort as it contributed about 40.1%).
- Cooling, add humidification if needed: Cooling is needed for about 1563
hours in a year, contributing to about 17.8% of thermal comfort. In Lagos,
and many other parts of Nigeria, however, cooling (air-conditioning) is not
as popular and heating is rare.

36
Figure 1.16. Psychrometric chart results for Lagos State, Nigeria showing design
strategies to achieve indoor comfort (Climate Consultant software)
1.6.3 The 2000-Watt Society
The 2000-Watt Society fights climate change by focusing on the issue of
inefficient energy use (Griffith, 2022). This initiative’s target is used to examine
various interventions such as per capita energy usage, energy intelligence, and
community-based action plans.

37

Figure 1.17. Graph comparing the United States’ average energy use per person and
the goal of the 2000-Watt Society “One Target for All”
The idea of net-zero urban design is appealing for sustainable urban
development, but its feasibility in Lagos, Nigeria is often questioned. This comes as a
result of obstacles that accompany the region’s socioeconomic relations and
environmental conditions. This factor puts a halt to the implementation of many
beneficial net-zero strategies, some of which include renewable technologies, like solar
panels. The practicality of incorporating solar panels in Lagos is insufficient due to
many factors. Initial costs and maintenance costs make solar technology less attractive
in this case. Additionally, Lagos’ dense urban population and large levels of air
pollution can reduce the efficiency of solar energy collection (Ackermann, Andersson
& Soder, 2001). The socioeconomic background of Lagos makes matters even more

38
difficult. For the majority of its residents, the immediate and urgent need of housing
and survival overrides the investment required for energy-efficient building techniques
(Ackermann, Andersson & Soder, 2001). While the vision of net-zero urban design is
alive, Lagos’ unique set of concerns pushes for a more personal strategy that can
effectively address these concerns.
1.7 Approach for Determining Energy Consumption
Software
Name
Software Use Website URL
EnergyPlus
Modeling and analyzing a
buildings’ energy
consumption
https://energyplus.net/
IES VE (Integrated
Environmental Solutions
Virtual Environment)
Energy modeling, thermal
comfort analysis, daylight
and solar analysis, building
regulations compliance
https://www.iesve.com/
Cove.tool
Automated building
performance analysis, Cost
vs. energy optimization,
3D modeling integration,
HVAC system design,
https://cove.tools/

39
energy modeling,
educational resources
Openstudio
Energy modeling and
simulation, HVAC system
modeling, Daylighting and
shading analysis, Scripting
and customization,
parametric studies and
design, reporting and
visualization
https://openstudio.net/
Autodesk
Insight
Energy and environmental
performance analysis,
carbon analysis, building
performance dashboards,
integration with Revit
workflows, Construction
project management
https://www.autodesk.com
/products/insight/overview
DesignBuilder
Energy and thermal
simulation, integrated
tools, user-friendly
interface, certification
compliance
https://designbuilder.co.uk/

40
Grasshopper - Ladybug
and Honeybee
Scripting, weather data
analysis, sun studies,
energy modeling, visual
solar radiation patterns,
building performance
simulation,
https://www.grasshopper3
d.com/
DOE-2
Energy efficiency analysis,
cost estimation,
compliance with energy
codes, research and
development
https://www.doe2.com/
eQUEST
Building simulation,
Wizards for Input, energy
performance evaluation,
output analysis
https://www.doe2.com/equ
est/
HEED (Home Energy
Efficient Design)
Design tools, utility and
carbon footprint
calculations, climate
contextualization tool to
help users improve the
energy efficiency of
residential buildings
https://www.sbse.org/resour
ces/heed

41
Climate Consultant
Visual representations of
climate data for building
design
https://www.sbse.org/resour
ces/climate-consultant
Rhinoceros 3D
Computer-aided design
(CAD) software used for
3D modeling
https://www.rhino3d.com/
By using software to modify the design of a preexisting multi-family urban
housing development net-zero energy can be achieved. The steps will be as follows:
1.8 Summary
This chapter discussed Nigeria’s rate of urban expansion and its crisis in
relation to the lack of energy supply that the country receives. It goes in to discuss what
urban housing is and its typologies, important, and international implications. In Lagos
specifically about 91% of the population live in the city making its population density
20,000 people per square kilometer. The most dominant forms of urban housing in the
world are apartment buildings. These urban housing developments are important
because they often provide an opportunity to use land efficiently. Urban housing
developments also foster a sense of community as they often provide space for public
areas and parks. The idea of urban housing was first brought to societies by European
models and were inspired by the Greco-Roman way of living. On a global scale,
homeless is typically came as a result of lack of adequate and affordable housing. In

42
Lagos, Nigeria, population growth can have a detrimental impact due to the lack of
infrastructure for energy reliability and limited resources to support its upkeep. Unlike,
many other African countries, Nigeria has a larger urban population than rural. In
Lagos, high energy consumption and population growth contributes to its own
challenges as its energy concerns are related to its economic state.

43
Chapter Two: Background Research
2.0 Introduction
Net Zero Energy (NZE) design is becoming relevant in African countries,
including Nigeria, as people are becoming increasingly aware of the need to reduce
energy consumption. The discovery and use of NZE passive design in these countries
come after various studies, projects, and the formation of policies that are targeted at
design modification and the promotion of energy-saving building practices. These
efforts are taken to obtain sustainability and reduce energy consumption and
dependency. In Africa, the movement toward NZE design has been gaining attention,
with countries like South Africa and Kenya developing buildings that comply with
NZE standards (Keeler & Vaidya, 2016). These enforcements are benchmarks for
sustainable NZE practices across the continent (UNEP, 2021). Nigeria’s engagement
in NZE design is remarkable because it focuses more on improving the country’s
reliance on unpromised energy sources. A project conducted by the Energy
Commission of Nigerian and the Sustainable Energy of All (SEforALL), spelled out in
“Nigeria’s Renewable Energy Master Plan,” shows Nigeria’s attempts to incorporate
solar energy into building design to achieve net-zero energy consumption (ENC, 2020).
Nigeria’s adoption of best practices and renewable energy policies, such as the National
Renewable Energy and Energy Efficiency Policy (NREEEP) shows the government’s
commitment to promoting these NZE designs and serving as a basic foundation for
future constructions (Rural Electrification Agency, Damilola Ogunbiyi). “Advancing

44
Net Zero: How the Global Building Sector is Leading the Way to a Zero Carbon
Future” dives into why these advancements are essential in launching Nigeria, and
Africa as a whole, towards a more sustainable future made up of improved energy
efficiency and enhanced living standards for its residents (World Green Building
Council, 2022).
2.1 Urban Housing Successes in Developing Countries
This section is about the countries that have successful net-zero urban housing
developments that contribute to the good of people. Three case studies (SIDAREC
Community Center, The Sankofa House, and the Mahindra World City) show how low
energy building are being done today.
Lynedoch Eco Village in Stellenbosch
In developing nations, specifically Africa, achieving Net Zero Energy (NZE)
urban housing success is most evident in the adoption of design and construction
methods in residential buildings. South Africa has proven to be a frontrunner in
implementing NZE strategies for urban development design (Munir, Naqvi, & Li,
2024). A great example of this is the energy-efficient and net-zero techniques that are

45
seen in the Green Building Council’s headquarters in Cape Town that aim to positively
impact urban housing development (GBCSA, 2019). The country continuously
improved its green building practices, with the Green Building Council of South Africa
categorizing Net Zero practices into carbon, waste, water, and ecology (World GBC,
2019). These categories are integral to the design of South Africa’s green buildings to
promote sustainability in residential living. The Lynedoch Eco Village in Stellenbosch
is a prime example of this model. It is a sustainable community that focuses on the
implementation of passive design strategies and water efficiency to create an
environment that urges to decrease the footprint that the city leaves (Sustainability
Institute, 2021). All of the materials used to design Lynedoch are alternative, consisting
of bricks, bales, and sandbags.
Kenya has taken similar advances when it comes to the incorporation of NZE
design. Coveted developer, Superior Homes, is a residential project that aims for and
is leading the way in energy efficiency (Koech, 2020). While its foundational design
systems are relatively similar to the process of a non-NZE home, its use of energyefficient accessories helps reduce energy consumption overall. The country’s LongTerm Low-Emission Development Strategy (LT-LEDS) shares a similar goal to the
NREEEP: directing Kenya toward a net-zero future. Nairobi’s Kounkuey Design
Initiative focuses on community-driven projects that use sustainability practices in
design that extend to the overall goal of improving living standards and conditions as
well (KDI, 2021). An example of passive NZE design in Kenya is the SIDAREC
Community Center, located in Mukuru Kwa Njenga, Nairobi, which uses passive solar

46
design for natural ventilation and daylighting to achieve thermal comfort (Fivedot
Architects). The construction of this project consisted of careful planning and climate
analysis to further contribute to the durability of the community. SIDAREC also uses
these techniques to decrease the necessity of heating and cooling as its orientation and
structure are well thought out to maximize the benefits both (Lohr, Holliday, Dye,
Lopez, & Cooley, 2008).
Figure 2.1. SIDAREC Community Center in Nairobi, Kenya (Fivedot Architects)
Mahindra World City in Chennai, India
The Mahindra World City in Chennai, India is another prime example of
sustainable urban housing. It offers a wide range of facilities, including residences, and

47
has gained recognition as a successful model for sustainable living. According to the
U.S. Green Building Council (USBGC), it serves as India’s first and one of the largest
integrated business, work-live city (Piparsania & Kalita, 2021). The project integrates
green building systems and renewable energy sources that aim to balance energy
consumption and generation onsite. In the “World City,” designers focused on creating
Net Zero Energy (NZE) homes by implementing green spaces, water conservation
methods, and courtyard gardens, in attempts to lead from a passive design perspective
(Figure 2.2). This development denotes a shift in traditional Indian building practices
to more sustainable and energy-efficient housing solutions. It highlights the potential
that lies in integrating NZE principles into the design and construction phases of new
urban housing developments, which can effectively address the challenges posed by
climate change and rapid population growth.
Figure 2.2. Chennai, India’s Mahindra World City (Mahindra Lifespaces)

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The city’s design was based on Chennai’s weather conditions featuring both
tropical wet and dry climates. Because it is located on the southeastern coast of India,
it experiences high temperatures throughout the year. During the summer temperatures
range from 95 degrees Fahrenheit to 104 degrees Fahrenheit, with May being the
hottest month of the year. During the monsoon season, July to September, temperatures
go down due to rain spells but remain warm, ranging from 82 degrees Fahrenheit to 95
degrees Fahrenheit. Chennai winters usually span from November to February with
temperatures ranging from 68 degrees Fahrenheit to 86 degrees Fahrenheit (Figure 2.3).
To address the challenges that come with Chennai’s weather, designers incorporate
high-performance building materials that provide better insulation and reduce internal
heat gain. The World City was designed with features such as reflective building
materials, exterior shading, and double-glazed windows to minimize heat intake and
reliance on cooling systems.

49
Figure 2.3. Relative temperature and humidity of Chennai, India’s Mahindra World
City
The orientation of the buildings is planned to take full advantage of the ventilation and
natural light that is experienced throughout the city (Figure 2.2). This was done to
decrease the amount of artificial lighting that is needed to keep the city operable.

50
Figure 2.4 Psychrometric chart of Chennai, India and its respective impact
of design strategies (Cove.tool analysis)

51
The Sankofa House in Ghana
In Ghana, ancient architecture has been demolished for more modern
constructions, leading to buildings made of cement blocks and other industrial
materials that are almost always costly and imported (Azunu, 2017). These cement
blocks provide little to no insulation to the regions that often need it the most. In
Abetenim, a village in Ghana, almost all of the homes are built with local red earth
because it is available in larger portions for free (Azunu, 2017). However, after years
these homes begin to blend or become damaged due to rain and lack of maintenance
(AiD, 2021).
The Sankofa House in Ghana demonstrates how local materials and passive
architectural strategies can be utilized to create sustainable and energy-efficient homes
in less-developed parts of Africa. Designed by M.A.M.O.T.H., and located in
Abetenim, Ghana’s Ashanti kingdom, the Sankofa House is part of a larger effort to
develop affordable, eco-friendly housing (Homod, Almusaed, Almssad, Jaafar,
Goodarzi, & Sahari, 2021). The project uses a range of passive design strategies to
decrease energy consumption in a tropical climate that often relies heavily on unreliable
energy sources. Similarly to Kenya’s SIDAREC center (see Figure 2.1), the redesigned
home features strategies orientation in attempts to take full advantage of solar gain for
daylighting and heating during cooler parts of the year, and to enhance cross-ventilation
for cooling during warmer periods (see Figure 2.5). The use of thermal mass in
materials such as blocks can be used to regulate indoor temperatures throughout the

52
day and night (AiD, 2021). The rehabilitation of this traditional Ghanaian home aspires
to bridge traditional and earthly architecture into global climate approaches that
reintroduce comfort (AiD, 2021). Its landscaping and surrounding vegetation are
designed with native plants and trees to shade and reduce overall heat gain. Sankofa is
a courtyard home with sloped roofs and a bright exterior facade color. Its simplicity
mimics Ashanti buildings. It is oriented north to south and consists of large, covered
outdoor areas organized around a main central courtyard. Its use of terraces allows for
natural ventilation. It serves the purpose of producing a building that is easy to replicate
and adapt to. The Sankofa House is characterized by sloped roofing that draws a
“skyline” and generates sufficient thermal comfort compared to the cement, flat roofs
that are typically used in this region and all over Ghana.
Figure 2.5. Sankofa House passive design diagram (AiD, 2021)

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Figure 2.6. The rehabilitated Sankofa House in Ghana’s Ashanti Kingdom (AiD, 2021)
2.1.2 Systems and Methods that Work
Due to increased urbanization and environmental issues, developing countries
have adopted passive net zero energy (NZE) design systems and methods to provide
adequate urban housing. These systems and methods contribute to the global

54
sustainability goals spelled out in the United Nations’ Sustainable Development Goals
(SDGs), specifically Goal 11 (SDG 11) which aims to make cities and human
settlements inclusive, safe, resilient, and sustainable (United Nations website). By
integrating specific techniques, cities can ensure that SDG 11 is achieved while making
buildings liveable and resilient for their residents. Achieving this goal by means of
architectural design requires a diverse approach and comes with many options:
● Mixed-Use Development: “Bring together residential, commercial,
and recreational areas to minimize the reliance on transportation,
improve convenience, and promote community engagement”
● Green Spaces: “Enhance the quality of parks, gardens, and green
spaces to boost air quality, offer leisure spots, and support
biodiversity”
● Sustainable Building Codes: “Implement green building
regulations that promote the use of sustainable materials, energyefficient practices, and water conservation in construction”
● Strengthen Resilience to Climate Change: “Enhancements to
infrastructure and materials, along with strategic planning efforts, to
boost the city’s resilience in the face of natural disasters or
obstructions”
● Support of Affordable Housing Initiatives: “Create policies and
initiatives that enhance the accessibility of reasonably priced,

55
sufficient, and safe housing options, guaranteeing that every
individual has the opportunity to enjoy decent living conditions”
● Fostering Community Participation: “Get communities involved
in urban development and the decision-making process to make sure
that the personal needs of residents are taken care of and also to
educate them”
● Reflective Materials in Construction: “Incorporate materials with
high solar reflectance in urban surfaces, such as roofs and
pavements, to reflect more sunlight and absorb less heat which is
essential for Lagos, Nigeria”
● Inclusion of Urban Planning for Climate Adaption: “Create,
plan, and design urban spaces that can withstand the effects of
climate change, such as higher temperatures and more frequent
extreme weather, by incorporating natural features like floodplains
and permeable surfaces to manage water”
Many methods can be used to achieve net zero energy. Of these methods is
industrialized housing construction: a method used to describe a business model and
technical orientation that links design and fabrication using an integrated building
process and organizational structure. In a case study carried out by ARUP in 2018,
researchers assessed the potential requirements for housing in developing countries:
Kenya, Ethiopia, and South Africa. It was found that regardless of the specific strategy
that was applied, several benefits were identified when industrialized construction (IC)

56
concepts were integrated into the house-building process as opposed to conventional
construction (ARUP, 2012). Some of these benefits include safety improvements,
weather independence, improved quality, shorter completion times, and higher cost
predictability all while potentially reducing environmental impact.
2.1.3 Habitat for Humanity Guide
Because developing countries often face economic challenges in the context of
affordable housing, Habitat for Humanity’s guide on Net-Zero homes shows solutions
to the housing crises in low-income nations, playing a key role in achieving targets
despite global climate issues and constraints. Despite economic challenges, circular
models and region-specific frameworks can help reduce emissions through passive
design in the earlier stages of building construction.
Narrow flows (using less), slow flows (using longer), regenerating flows
(making cleaner), and cycling flows (using again) are methods of design that minimize
resource extraction and the dispersion or loss of materials. Narrow flows require
circular design, a process that reduces material usage rates and includes climateresilient building practices and prefabrication of local components.
In the Philippines, precast and engineered, local bamboo is often used in the
design of many NZE residential buildings (Wang & Ng, 2023) (Habitat for Humanity).
The Kanya Kawayan Weaving Center, an initiative by the Houses of Tomorrow, is an

57
exemplary housing project that incorporates a unique prefabricated framing system.
This system is specifically designed to withstand natural disasters such as earthquakes
and fires, ensuring the safety and security of its residents. The utilization of bamboo in
the design and fabrication of this system not only contributes to the overall goal of
sustainable residential building development in the Philippines but also significantly
reduces its environmental impact. It has been found that the bamboo system has a 60%
smaller footprint compared to the conventional structural materials typically used by
builders (Holcim, 2022).
The “slow flows” method explains the importance of using durable materials
that can be simply repaired or disassembled when needed, extending their lifespans. In
Kenya, the use of precast hollow concrete blocks is specifically tailored towards lowincome development to optimize floor plans and building process efficiency, while
increasing a building’s amount of ventilation. The same type of idea is translated into
India’s adoption of modular, lightweight paneling systems that are structured to provide
insulation that aims to keep heat out and reduce indoor temperatures by a margin (Wang
& Ng, 2023) (UN-Habitat).
In countries like Nigeria, which have a tropical savanna climate, it is essential
to use a combination of architectural and non-architectural methods to create energyefficient buildings that are tailored to the local conditions (Ogbuokiri, 2008). The goal
is to take advantage of the climate's characteristics - warm, overcast, with a distinct
rainy season - to reduce energy usage while ensuring that occupants are comfortable.

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Architectural strategies play a crucial role in achieving energy efficiency. One
important aspect is the use of energy-efficient windows, skylights, and doors designed
specifically for the tropical climate (Bülow-Hübe, 2001). These can significantly
reduce the need for artificial lighting and air conditioning, resulting in both energy and
cost savings. These systems also promote natural ventilation and lighting, reducing
reliance on mechanical systems.
Another key area for improving energy efficiency is water heating. In cities like
Lagos, high-efficiency heat pump water heaters or solar water heaters are viable
options. These take advantage of the abundant sunlight while reducing electricity
usage. Similarly, energy-efficient refrigeration is important for reducing power
consumption in a region where cooling is always needed. Landscaping is often
overlooked but can provide significant benefits in energy-efficient building design,
especially in tropical climates (Bülow-Hübe, 2001). Strategic placement of trees and
vegetation can provide natural shading, helping to cool buildings and reduce cooling
expenses. Additionally, proper insulation of building envelopes, including ceilings,
walls, and floors, is crucial for maintaining a comfortable interior temperature without
excessive energy consumption (Goodchild, 1994). This approach is particularly
important in Nigeria, where current building practices often overlook these
considerations. Materials such as cellulose, fiberglass, or environmentally friendly
options like sheep's wool can be used based on their availability and cost in Nigeria.

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Ventilation plays a crucial role in maintaining the quality of indoor air and
ensuring that energy efficiency is not compromised. By implementing systems that
provide fresh and filtered air, one can greatly enhance comfort levels and effectively
manage moisture, especially in regions with high humidity like Lagos. To further
optimize energy usage, energy-efficient lighting such as LED lights can be utilized,
along with strategic building orientation and high-performance shingles that take
advantage of the unique characteristics of the site (Kwag, Adamu, & Krarti, 2019).
Each of these methods is carried out in the case studies mentioned earlier. Minimizing
waste and materials during construction by selecting a smaller building footprint and
utilizing resources efficiently is also essential. This may involve making changes to
materials, such as incorporating calcined clay, to reduce the carbon footprint.
Green roofs give numerous benefits as well, including reducing the need for
heating and cooling and acting as natural air pollutant filters (Rowe, 2011). The design
of the building, including its shape and location, has a significant impact on energy and
carbon efficiency. For example, a U-shaped design surrounding a courtyard or a donutshaped building with a courtyard at its center can maximize natural light and ventilation
(Rowe, 2011). Adjusting the orientation of the building's faces can also help manage
wind exposure and sunlight.
The approach to creating energy-efficient buildings in a tropical savanna
climate like Lagos's could be useful with a careful balance between architectural and
non-architectural strategies, however, to improve thermal comfort in a way that the

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majority of individuals can afford, passive design techniques serve as the more
promising solution. This includes everything from the choice of materials in early
design stages to the readoption of native ancient solutions. By considering the
building's occupancy, location, and specific environmental conditions, it's possible to
design structures that are both energy-efficient and suitable for the local climate,
ensuring comfort to individuals as well (Rowe, 2011).
2.2 Existing Urban Housing Typologies in Nigeria
The urban housing landscape in Lagos, Nigeria, comprises a diverse array of
typologies that reflect the city's socio-economic status, culture, and responses to
environmental challenges (Adewumi, 2020). Lagos, faces significant urban housing
challenges, including overcrowding, inadequate infrastructure, and a shortage of
affordable housing. The predominant housing typologies in Lagos can broadly be
categorized into formal and informal settlements, with the formal sector comprising
bungalows, duplexes, apartments, and high-rise condominiums, while the informal
sector is characterized by makeshift housing and slums such as the Makoko floating
community (UN-Habitat, 2014). Because Lagos is a more industrialized city with
characteristics that favor Los Angeles, California, the housing typologies that exist in
rural regions such as Enugu and Abuja, are almost always rarely seen there.

61
Bungalows and duplexes, often found in more wealthy neighborhoods,
represent the main traditional urban housing types in Lagos. These dwellings offer
more living space and are admired by residents for their privacy and architectural
flexibility (Adeokun, 2006). Apartments and high-rise condominiums are also
increasingly prevalent in response to the need for high-density housing solutions in the
city's congested areas. However, they are limited due to the amount of energy that is
required to maintain them. These multi-family units are often part of larger
developments that seek to optimize land use and provide amenities to residents
(Adelekan, 2010). In more recent years, there has been a gradual shift towards
introducing new housing typologies in Lagos that aim to address the city's housing
crisis while incorporating sustainable design practices. Although net zero energy
(NZE) housing developments are still in their beginning stages in Lagos, there is
growing interest in sustainable construction methods and renewable energy integration,
but just little knowledge on how to do so (Ezennia, 2022).
The NZE urban housing could either blend in with existing typologies or create
a whole new housing style. These fresh housing styles mark a shift from the usual
construction methods seen in Lagos to a more eco-friendly approach. Unlike the
traditional bungalows and duplexes that heavily rely on grid electricity and lack
sustainable features, these modern urban housing designs use passive design techniques
like natural ventilation, daylighting, and thermal mass to cut down on energy usage.
Additionally, incorporating green spaces and water-efficient systems in these new

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developments would provide a stark contrast to the overcrowded and poorly serviced
conditions often seen in Lagos's informal settlements (Nwokoro & Dekolo, 2015).
Despite the potential of these new housing typologies to transform Lagos's
urban landscape, the city's predominant housing remains divided between high-end,
formal constructions and low-income, informal settlements. A prime example of this is
the divide between the island and the mainland. Because of its location at the coast of
the region, Lagos poses a more complex issue as it is situated in between both lands
and this is evident when it comes to the overall typologies that make up the urban city
(Agamah, 2018). The concerns in housing quality and accessibility underscore the
challenges Lagos faces in achieving inclusive urban development. As Lagos continues
to expand its population, the need for sustainable, affordable, and adequate housing
solutions becomes increasingly urgent, highlighting the importance of transitions in
green technologies, and community understanding of NZE design in shaping the future
of urban housing in Nigeria's megacity (Olotuah & Bobadoye, 2009).
While Lagos has begun to explore sustainable and net zero energy housing
typologies as alternatives to its traditional housing models, the transition towards these
solutions is still in early stages.

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2.3 Existing Characteristics and Design Features of Nigerian Homes
This diversity of Nigerian architectural design is seen in characteristics and
design features that distinguish Nigerian homes across different regions. Traditional
Nigerian architecture has been deeply rooted in environmental sustainability, with
homes designed to attempt to optimize comfort in response to the tropical climate
(Nsude, 1987). However, this is typically found in the larger homes of high-income
families and on the more private lands that make up villages such as Enugu, Abuja, and
Owerri (Jiboye, 2014). These homes usually have high ceilings and large windows to
promote airflow. The use of locally sourced materials such as mud bricks, thatch, and
laterite is also common, showcasing an inherent sustainability in construction practices.
Courtyards are also a recurring element of these homes, serving both as a focal point
for family activities and a area that experiences natural cooling during hot temperatures.
In more urban areas, the influence of colonial architecture and modernist
designs has led to a blend of traditional and contemporary styles (Jiboye, 2014).
Bungalows and duplexes are dominate in these areas and serve as a model of the
adaptation of colonial-era designs to modern living requirements in the country.
Sometimes these typologies have verandas and balconies, extending the living space
outdoors while offering shade and protection from the rain (Nsude, 1987). In wealthier
urban neighborhoods, gated estates and high-rise condominiums exhibit a more
pronounced Western architectural influence, with amenities such as swimming pools
and landscaped gardens similar to the homes one may see in the United States.

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The design features of Nigerian homes also reflect the importance of social
interaction and communal living. Living rooms and courtyards are made big enough to
accommodate family gatherings and community celebrations (Jiboye, 2014). Security
features, including high perimeter walls and gated entrances, are also more common in
Nigeria’s larger neighborhoods.
In the northern regions of Nigeria, such as Kano and Adwa, homes often feature
traditional Hausa architectural elements, such as the 'Zana' (a perimeter wall), which
provides privacy and security (Emusa, 2017. The 'soro' (an elevated platform) is used
for sleeping outdoors during hotter months and makes for an existing passive cooling
strategy (Emusa, 2017). Southern Nigerian homes, particularly in coastal areas, may
incorporate stilts or raised foundations to protect against flooding, a design feature that
shows the adaptability of Nigerian architecture to its environmental context (Nsude,
1987).
In a series of ten interviews that were conducted over a month (see Appendix
A), it was found that most traditional homes are made up of concrete. The interviewees
included long-term residents of Nigeria and some of them owned homes in both the
country’s Northern and Southern regions. Of these interviews, all ten individuals lived
in a single-family home that was either semi-detached or detached. Eight of the ten
interviewees stated that their homes were located in the Southern part of Nigeria while

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the other two resided in Abuja, which is located in central Nigeria but closer to the
north. Individuals who lived in South Nigeria had also reported that they experience
dry seasons and minimal rainy seasons once in a while due to living in the tropics. In
Abuja, residents described the climate as more temperature and less humid which they
appreciated. It was found that Abuja’s temperature during the day was cooler than that
of South Nigeria. The average temperature of the interviewee’s homes throughout the
day was found to be 91.6 degrees Fahrenheit.
Seven individuals stated that they had access to air conditioning. Of these seven,
two had mentioned that heat was not needed as they hardly experience harsh winters.
The majority of the homes consisted of at least three bedrooms and two bathrooms
while rooms spanned about 10 feet by 12 feet or 12 feet by 12 feet. All of the homes
were at least two stories, and each bedroom typically had its bathroom connected to it.
Only one home was slightly elevated in comparison to its surrounding areas as the rest
were situated at ground level. Eight of the interviewees’ homes contained kitchens that
were isolated on the perimeter of the home or enclosed in the center of the home. The
remaining two homes had an open kitchen floor plan. Nine of the homes had balconies
or overhangs. Seven of the homes reported that they experience harsh winds that
produce sounds within the home through doors and windows. None of the interviewees
stated that they did anything to mitigate this issue throughout the year. Two of the
interviewees’ households have renewable energy, however, both had stated that they
are used at a minimum level.

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The characteristics and design features of Nigerian homes are a reflection of the
country's multifaceted identity, fusing together traditional with modern (Kashim,
Ogunduyile, & Adelabu, 2011). The homes are deeply intertwined with the cultural,
environmental, and social build up of Nigerian society. Because of this, as Nigeria
continues to develop, the evolution of its meaningful home designs do too.
Figure 2.7. Interview Questions for Nigerian Residents

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2.4 Software
This section overviews specific modeling and energy software, Rhino,
Grasshopper, Cove.Tool and Climate Consultant.
2.4.1 Rhinoceros 3D (Robert McNeel & Associates)
Rhino, or Rhinoceros 3D, is typically used by architects, engineers, and graphic
designers globally. The software models geometries in free-form and is also used when
it comes to creating, editing, and rendering objects into curves, surfaces, or solids
without specific limits (Zawarus, 2022). People usually use Rhino for more difficult
architectural designs, furniture designs, or product designs. Because the software
allows for a lot of precision, the 3D models can also be sent to other users for
collaborative projects and edited in other softwares like Revit and ArchiCAD.
While Rhino is beneficial for creating intricate 3D models, it does not have
work to automatically perform structural or thermal analysis like other CAD softwares
(Zawarus, 2022).
For energy simulation and building performance analysis, Rhino incorporated,
Grasshopper, a built-in scripting tool as a plug-in to the software..

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2.4.1.1 Grasshopper - Ladybug & Honeybee (Ladybug Tools LLC)
Grasshopper makesit is easier to provide parametric design models or
facade details with the use of scripts (Zawarus, 2022). The plugin is based on
connecting ‘breps’ to geometry and scripting that lets users get quick feedback and
adjust design features in a time efficient manner. It also helps users make repetitive
design changes without having to adjust every item one by one. Ladybug and Honeybee
are the main plugins that are accompanied by the use Grasshopper.
Grasshopper’s Ladybug plugin lets users import and extract data in
Rhino (Zawarus, 2022). It also allows its users to easily visualize and interpret weather
data, sun paths, and temperature changes. Honeybee is a more advanced plugin that
integrates energy simulation tools like Radiance and EnergyPlus (Zawarus, 2022),
allowing the simulation of building performance to compare different design options.
Honeybee detects how design options play a role in overall energy usage. It enables
modeling with materials, mechanical systems, and environmental features. The
Honeybee plugin is also an effective way to simulate heating, cooling, lighting, and
ventilation characteristics for specific climates, helping to achieve net-zero energy
building designs.

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2.4.2 Cove.Tool (Pattern r+d)
In Chapter 1.7, several software tools were discussed that could been used for
energy simulation in projects. Cove.tool combines architecture, engineering, and
sustainability to give feedback on the ecological footprint of the building (Hegedűs,
Tóth, Hajdu, Károlyfi, Horváth, & Szalai, 2024). The software is beginner-friendly and
easy to evaluate the recommendations of design strategies.
Cove.tool is praised for its accessibility and user-friendly interface when it
comes to setting up projects, entering data and running results. This means that users
do not need to have advanced energy modeling experience to work on projects. It works
by taking building parameters, such as geometry, location, material specifications,
mechanical properties, and putting them into an analysis process (Forouzandeh,
Tahsildoost, & Zomorodian, 2021). Data from Cove.tool is entered manuallt or
imported from a 3D modeling software program like Rhinoceros 3D, Revit, or
Sketchup using login information and/or Grasshopper scripting. Once data is entered
in the system, cove.tool uses algorithms to produce energy usage results and provide
baselines to the existing project.
While Cove.tool is fairly easy to use, it comes with limitations. Building
geometry that is not planar is often not readable by the tool as geometry inputs are
restricted to planar inputs. This means that if a model’s geometry consists of circles or
curves, the data is often misread or not able to be simulated in Cove.tool. Because of

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this, cove.tool cannot replace detailed manual calculations, or analysis, especially in
the case that a project has a more complex design (Forouzandeh, Tahsildoost, &
Zomorodian, 2021). The tool is most useful when used with other analysis methods or
when used to check work.
Cove.tool’s accuracy when it comes to simulations mainly depends on how
accurately the data is put in. Data may not be updated in the database at certain points
of the project analysis. The software brings in environmental data from public and
private databases to make sure that multiple scenarios are accounted for and that data
is as recent as possible (Forouzandeh, Tahsildoost, & Zomorodian, 2021). The
software’s use of weather data files and information about the specific location that one
plans to observe provides a large variety of climatic conditions from the selected
location. Incorrect data about the building’s geometry or features could result in issues
in the simulation’s final outcomes.
2.4.3 Climate Consultant (Energy Design Tools at UCLA)
Climate Consultant is a software that serves to analyze weather data and aid in
making smart choices when it comes to passive architectural design strategies. It was
developed by the UCLA Energy Design Tools Group. It is primarily used in the early
stages of design to encourage projects that are customized according to their unique
environmental settings (Milne, Liggett, & Al-Shaali, 2007).

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Each Climate Consultant EPW file has details for the site’s temperature,
humidity, precipitation, and cloud coverage. Once an EPW file is input, the software
analyzes the data and produces diagrams and graphs based on the parameters and
specifications that the user has chosen (Milne, Liggett, & Al-Shaali, 2007). These
visualizations help understand how the specific climate currently affects the site’s
performance.
Similar to Cove.Tool, Climate Consultant’s accuracy also relies heavily on the
accuracy of the data that is put into it. The EPW files that the software uses are obtained
from worldwide data that hold weather data (Milne, Liggett, & Al-Shaali, 2007). The
output accuracy can be limited in the case that long-term climate changes occur and are
not updated or reported in the system (Milne, Liggett, & Al-Shaali, 2007). Data files
can also be broad and not include site-specific data such as topographic characteristics
or urban heat islands.
2.5 Recent Energy Simulation Research in Nigeria
There are many example of energy simulation research in Nigeria that has
been carried out in recent years. In an article entitled “Analysis of HighPerformance Residences in Nigeria”, the energy performance of Nigeria’s
residential buildings was analyzed in attempts to improve its energy efficiency
(Kwag, Adamu, and Krarti, 2019). The study analyzes different energy-saving
measures for these residential buildings and uses modeled simulations to determine

72
how much they impact overall energy consumption. The authors, Kwag, Adamu,
and Krarti, underlined how important passive design strategies re in Nigeria’s
climate. The study showed that passive design strategies, such as shading an
insulation, have a massive impact on how efficient energy performance is in
Nigerian homes (Kwag, Adamu, and Krarti, 2019). The study also found that the
integration of advanced glazing and tailoring energy-saving measures to
specifically meet the needs of Nigeria’s climate is critical when it comes to reducing
dependence on air conditioning in the homes that have it (Kwag, Adamu, and
Krarti, 2019).
“Modelling the Impact of Nigerian Household Energy Policies on Energy
Cosumption and CO2 Emissions” by M.O. Dioha dives into the potential outcomes
of instilling various energy policies on household energy consumption. This study
used dynamic modeling approaches of systems to depict how different policies
would impact Nigeria’s housing sector. The study found that Nigeria’s household
energy consumption is predominantly biomass (firewood and charcoal) in many
rural areas (Dioha, 2018). The study also emphasized the important of strong
government policies like clean energy technology subsidies, awareness programs,
and investments in new infrastructure (Dioha, 2018). Encouring new clean energy
led to significant reductionsin energy consumption and carbon dioxide emissions
inside of Nigerian homes.

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The article “Low-Cost Retrofit Packages for Residential Buildings in HotHumid Lagos, Nigeria,” by N.C. Onyenokporo and E.T. Ochedi, explores
economically-friendly retrofitting techniques that can be used to improve the
energy efficiency and thermal comfort of residents in Nigeria. The articles
highlights the ranges of affordable interventions that are tailored to Lagos
specifically. Retrofitting packages that were featured in the study include shading
devices to reduce solar heat gain, improved insulation natural ventilation, and
reflective roofing (Onyenokporo & Ochedi, 2019). The study concludes that lowcost retrofit measures are viable and effective for improving energy efficiency in
the residential sector and climate-sensitive areas.
2.6 Summary
This section discussed the countries that have successful net-zero urban
housing developments that contribute to the good of people. Three case studies
(SIDAREC Community Center, The Sankofa House, and the Mahindra World City)
were analyzed and showed how low energy building are being done today. Of the
three case studies, the Sankofa House utilized the majority of passive design
strategies. The Mahindra World City was designed in attempts to achieve NZE
energy efficiency at a larger scale.

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Chapter Three: Methodology
3.0 Methodology
The workflow for the energy simulation-based Net Zero Energy (NZE) design
is discussed in this chapter (Figure 3.1). This workflow includes a site and climate
analysis, a parameter hunt of design elements, an existing case study modeling and
analysis, and a new case study analysis and design modification. A comparison and
future work recommendations will be also carried out. The main research process will
consist of modeling the existing case study, evaluating existing weather characteristics,
design strategy studies, implementation of chosen parameters, and a performance
examination. The procedure carried out to perform these tasks will be spelled out
throughout this chapter.

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Figure 3.1 Workflow methodology diagram
3.1 Site and Climate Analysis
A thorough site and climate analysis of Lagos, Nigeria will be carried out using
Rhinoceros 3D (Rhino) software and Grasshopper’s Ladybug and Honeybee tools.
These tools will be used to further analyze the tropical climate that accompanies the
city where the case study site is located. This analysis is essential because it shows
what can be done to optimize the environmental resources that are provided by the
region’s natural features and can make the site more comfortable for humans The
chosen climate will be analyzed by use of a Ladybug Tools (LBT) EPW file that will
be connected to a Rhino Grasshopper script.

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3.1.1 Climate Data
The first part of this analysis will consist of climate data visualization. The
visualization will depict the climate’s monthly dry bulb temperature range, ground
temperature, dew point temperature, and sky coverage. Specific weather information
from an EPW file in Lagos, Nigeria will be gathered and uploaded into a panel, then
connected to a Grasshopper script. Grasshopper will visualize the outcome of this
weather data file. After this, it will a wind rose and sun path diagram to visualize the
wind speed and show how much the sun will impact the city throughout the year. The
wind rose will also show what direction the wind comes from in various parts of the
year in Lagos, Nigeria.
The geometry and EPW weather data files will be analyzed using the
Grasshopper’s Honeybee feature. The building’s geometry, material properties, and
other details will be put into Honeybee and the building’s energy consumption and
ability to maintain indoor comfort will be visualized in the Rhino window. These
simulations will provide information and hint at the various design strategies that can
be used to achieve energy efficiency for the existing buildings.

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3.1.2 Zone Measures
The second part of the analysis will consist of uncovering thermal comfort zone
measures. The outcome will show what months outdoor temperatures exceed, fall
below, or fall within the thermal comfort zone. The amount of heating- and coolingdegree days that the climate has will also be studied to determine which months
sunshine can be used as a source of heat and which months a shading device could be
incorporated to control overheating.
The entire analysis will incorporate the use of parametric tools in Grasshopper
for initial modification of design parameters. Real-time variables and inputted
components will be updated during the process and the models will then be updated
automatically. The of the simulations conducted using the Grasshopper plugin and
usually accurate depending on the specific parameters that the user initially entered.
Because of these possible errors, the simulated model will be compared against local
benchmarks to make sure that its starting point is precise and accurate. This validation
period will aid in calibrating the model correctly and refining the simulation results to
reflect the real-world performance characteristics of the existing design.
3.2 Parameter Hunt
This section of the methodology will include a thorough and extensive search
of parameters to reveal and assess passive design strategies based on the use of software
tools and knowledge. The parameter hunt will be carried out with the use of cove.tool

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and Climate Consultant to create potential design strategies. Cove.tool will be used to
evaluate the energy efficiency after various architectural changes. Climate Consultant
will provide valuable information on the strategies that are most effective in Lagos’s
climate.
To enhance these strategies, a set of interviews will be conducted with ten
residents in Nigeria. These interviews help better understand the current housing
situation and experiences of locals. They will also provide more information on the
layout and design of specific homes in Nigeria and how their program effects the
interviewee’s lifestyles on a daily basis. During the interviews, specific opinions on
current living conditions, residents’ ideas of thermal comfort, their preferences for
thermal comfort, and stance on design changes and modifications will be obtained.
Incorporating the perspectives of locals will help determine whether or not proposed
modifications can be implemented to meet ZNE goals and requirements but also blend
in with the culture and practices in the daily life of Lagos, Nigeria. Some of the results
of these interviews are in Chapter 2.3. More information can be found in Appendix A.
The next step is a detailed research portion of the parameter hunt. During this
portion, a literature review of existing case studies occur. Existing net zero urban
housing developments that have attempted to design for climates worldwide that are
similar to Lagos’s will be studied. Additional design parameters will also be uncovered
during this phase.

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After collecting and examining the data from the parameter hunt, the parameters
will then be organized into three different lists. These lists will be used as a guide for
making rational decisions during the final modification design process. The first list
will arrange the parameters from least to most effective and will prioritize their
potential impact on occupant comfort. To evaluate their effectiveness, the simulation
results and feedback will be compared and considered.
Each list will emphasize each parameter’s compatibility with Lagos and take
into consideration the city’s unique conditions. The strategies that best fit into the local
environment and consider available resources will be organized and incorporated into
the final design process.
3.3 Existing Case Study
The selection of the existing case study will be made with the intention of
retrofitting it to achieve zero net energy. To make sure that a good case study is chosen,
multiple potential case studies of urban developments in Lagos will be considered. New
developments and single-family housing were ruled out of the case study search as the
study will focus on urban housing. When simulations, or energy conservation methods,
are done, case studies will be analyzed using academic databases and websites, reports,
and journal articles.

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Once the case study is chosen, baseline data gathering will be conducted.
Energy bills will be collected from the building’s residents and calculated to reflect
the overall energy consumption of the building as a whole instead of as separate units.
Monthly billing information will be obtained to evaluate current usage patterns. The
collected baseline data will then be carefully analyzed to determine the main drivers of
energy consumption and areas where design changes would have the greatest impact.
The baseline analysis will be reported in an Excel spreadsheet to ensure that all data is
kept and updated accurately when needed.
The modification solutions will then be identified after collecting baseline data
and incorporating sustainable building practices from literature. These design strategies
will then be incorporated and obtained from the parameter lists into the existing case
study’s redesign.
3.3.1 Modeling of Existing Case Study
The case study will involve planning of the retrofitted deisgn. All background
information, including architectural drawings, site photos, measurements, plans,
material details, and environmental context will be gathered before Rhino modeling
takes place.
The Rhino window will be configured to the user’s convenience. Units, scales,
and layers will be set to preferred settings. Components will be created and named

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according to what is needed to keep the design organized in the window. Each layer
will contain various parts of the building such as its doors, floors, walls, roofs, facades,
interior walls, different stories, and windows.
The geometry will be modeled and created to match the real-life, existing
structure. For the existing case study, AutoCAD floor plans files or existing PNG
images of the building’s plan will be imported to ensure accuracy when modeling.
Rhino’s drawing features will be used to precisely follow the blueprints of building and
sketchy the shapes identically. The sketches will then be configured or extruded using
Rhino’s “extrude surface (SRF)” command to form the 3D structure and make sure that
the measurements in the pane depict the scale of the building in real life.
Once the basic 3D model is ready, windows, doors, and other features will be
added to the model as surfaces to be more convenient for the energy modeling phase.
Pre-made shapes and new curves will be applied to the model to serve as these
elements. Texture will also be used to render the model in Rhino. This will allow for
material identification when viewing the final model in Rhino’s ‘Rendered’ mode.
3.3.2 Cove Tool Analysis
Comparison with original data will occur to justify accuracy and adjust
properties if needed. Energy conservation methods will then be used to begin the
modification process. Each energy conservation method (ECM), or design strategy,

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from the three developed lists, will be modeled in Rhino and applied to the existing
case study. A new baseline energy use intensity (EUI) for each ECM will be determined
using the Cove.Tool plugin. Once all of the simulations are completed, ECMs will be
grouped and analyzed in groups.
3.4 New Case Study
A new case study design modification and simulation study will occur. Once
the correct design methods are chosen, the existing model will be retrofitted. In this
case, elements that are not changing will be copied to a different location in the plane
and modifications will be designed in Rhino. In the case that the modifications require
rebuilding of the entire model, the entire model will be rebuilt to depict the chosen
ECMs that will be in the final design.
3.4.1 Design Modification and Simulation
A new case study design modification and simulation will be carried out. This
will consist of a volume form study to determine the efficiency of the building’s shape
and its relation to optimizing surface area. Upon completion of the following and with
the incorporation of chosen parameters that will be found, the existing case study will
be redesigned. The parameters will be chosen from a list that specifically fits the needs
of Nigeria (See 3.2). This will be done in Rhino and based on the feedback of interviews

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that will be conducted over the course of one month. This redesign will implement the
use of passive design strategies.
The modified case study will incorporate the redesigning of the building and
volume studies that will later be translated into a larger scale design of the final model.
The initial background information of the site may change depending on design
changes. Because of this, a new collection of architectural drawings, site
documentation, dimensions, plans, and material characterization must be obtained.
Cove.Tool and Grasshopper simulations will then be run again to allow for a
detailed performance analysis of the new energy usage and thermal comfort. These
simulations will then prove that the refinement of design in the existing model was a
promising way to achieve net zero energy urban housing in Lagos, Nigeria.
3.5 Summary
Rhino’s viewport layouts will be customized again to fit the needs of the user.
Units, scales, and layers will be duplicated or modified depending on the project. If the
project was also modified by use of floor plans, they can be imported into Rhino and
traced again to ensure the dimensions of the new design are accurately modeled in the
software. Cove.Tool and Grasshopper simulations will then be run again to allow for a
detailed performance analysis of the new energy usage and thermal comfort. These

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simulations will then prove that the refinement of design in the existing model was a
promising way to achieve net zero energy urban housing in Lagos, Nigeria.

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Chapter Four: Simulations
Chapter 4 focuses on the analysis of the existing case study, the modeling
of the existing case study, its energy usage, and energy conservation methods:
building and form, passive solar design, and high-performance building envelope.

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4.0 Analysis of Existing Case Study
This chapter presents the simulations conducted to evaluate the performance
of various energy conservation methods when it comes to achieving net-zero energy
(ZNE) and analyzing their outcomes for multi-family homes in Lagos, Nigeria. The
main focus of these simulations is to test the standing hypothesis: by taking a typical
multi-family home in Lagos, modifying it with passive design strategies, and
simulating its performance, at least forty percent more energy will be saved, bringing
it closer to ZNE and making it more comfortable for its occupants. These simulations
are also used to address the following research questions:
● How can the housing crisis be addressed regardless of Nigeria’s
current economic situation?
● What can be done to housing to mitigate the disadvantages that occur
when power is taken?
● Which strategies are most effective in maximizing energy efficiency
in ZNE housing design in countries similar to Nigeria?
Furthermore, the chapter assesses the applicability of simulation tools like
Cove.tool and when it is most beneficial in the design stage.
Lagos has an average baseline Energy Use Intensity (EUI) that exceeds
global benchmarks. It is calculated by the energy consumed by a building in one
year (measured in units of kWh) by the floor area of the building. It is most
commonly expressed as a unit of kWh/m²/year. As of recent years, the national

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average baseline EUI of Nigeria is approximately 166 kWh/m² annually. While this
is low in comparison to the United States national average of about 300
kWh/m²/year, it is an accurate value for Nigeria as energy consumption differs
immensely. In Nigeria, estimates for single-family residential buildings range from
50 to 90 kWh/m²/year while commercial buildings are estimated to use about 150
to 200 kWh/m²/year. Current homes in Lagos predominantly rely on inefficient
design strategies, with natural ventilation, overhang shading devices, and roof
insulation being the most popular methods used to conserve energy. However, these
strategies alone fall short of the efficiency needed to achieve ZNE and increase
thermal comfort in residences. While HVAC systems are present in some local
homes, the ones that do have air conditioning units often struggle with getting cool
air to blow out due to the Lagos climate, so residents result to keeping the systems
off. The simulations run in this chapter, and the effectiveness of promising energysaving strategies in comparison to this baseline, are just starting point for the
potential improvement of designs in Lagos’ residential division will be provided.

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Figure 4.1. Home with and without Overhangs or Balconies in Nigeria
4.1 Modeling of Existing Case Study
The chosen structure was a standard multi-family residential building in Lagos,
Nigeria, that aimed to showcase what an average urban housing unit looks like in the
area. The building was strategically picked out as its initial features mirror the usual
construction methods, materials, and energy habits found in Lagos. Its base model has
three stories and covers a total floor area of 5,779 square feet, or 537 m², mainly built
from concrete/block materials and other prevalent local materials like cement blocks,
laterite, and bamboo. Therefore unit is about 89.45 m² (Figure 4.2). The building, or
34b Hope Apartment Complex, faces north-south, which plays a role in how much solar
heat it absorbs during the day and how comfortable residents are during different parts

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of the year. It has a flat roof with no insulation, and the windows are single-glazed,
which is pretty standard for most buildings in Lagos, where energy-efficient designs
aren't a big focus yet. The ventilation system is pretty basic. It relies mostly on natural
airflow, and it comes with regular household appliances that add to its overall energy
use. Each unit is comprised of the following program elements: two bedrooms, three
bathrooms, a living space, an entry way, a kitchen, and a covered porch.
Figure 4.2. Measurements of Existing Building’s Individual Spaces

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Figure 4.3. Ground-Level Floor Plan of Existing Structure
Figure 4.4. Floor Plan of 2nd and 3rd Stories Existing Structure

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Before any changes were made, the building had an Energy Use Intensity (EUI)
of 156 kWh/m² per year, which is around the standard for similar structures in Lagos
as its national average, mentioned above, is 166 kWh/m²/year (Cove.Tool Reports
Analysis). The absence of effective shading and the building's high thermal mass means
that it often soaks up heat during the daytime, contributing to an even greater need for
cooling the atmosphere. The main energy sources for this place come from the local
electricity grid, but occupants often rely on diesel generators because of regular, sudden
power outages. Residents also use passive techniques like cross-ventilation to stay
comfortable when the power goes out (Figure 4.5). Beds are often kept right next to the
window in preparation for the humidity that one may face throughout the night. This
building was chosen for simulation due to the fact that it reflects the majority of homes
in the area that are in desparate need of updates to achieve the city’s Zero Net Energy
(ZNE) 2030 target of 33 kWh/m² annually. By tweaking the current design with passive
strategies like building orientation and designing, high-performance building
envelopes, improved natural airflow, and materials selections, the simulations will
estimate how much energy can be saved and what needs need to be met to push the
building closer to ZNE. This first phase acts as a starting point for future simulations
and changes to see how they affect the overall energy efficiency and comfort for the
individuals living there.

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Figure 4.5. Air Conditioning vs. Cross Ventilation usage in Nigeria
4.1.1 Rhino 3D Simulated Model
The earlier results from the pre-simulation phase shed light on some key aspects
of how energy performs in the selected structure, which also reflects the performance
of homes across Nigeria. The first round of simulations shows that the building's poor
insulation and inefficient windows cause a lot of heat to build up during the daytime,
leading to an increased demand in cooling needs. Even
natural ventilation, the building's Energy Use Intensity (EUI) is still expected
to sit far beyond the target for Zero Net Energy (ZNE). It is categorized as a multifamily
housing unit for 2030 building type standards. For heating and domestic hot water
usage, the building primarily uses gas, a common choice in Lagos where gas is more
dependable and easier to access than electricity.
The initial model of the simulated building showcases various thermal
performance traits that serve as a starting point for determining its energy efficiency.

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The roof has a U-Value of 0.255 W/m²K, which means it has a decent level of thermal
resistance, but could be significantly improved. This suggests that the roof is made up
of Polyisocyanurate (PIR) boards that are founded locally in Nigeria, but are not always
the most suitable option in Lagos due to its heat sensitivity and moisture issues that
occur in hot-humis climates. The walls, made up of reinforced concrete frames, come
in with a U-Value of 0.566 W/m²K, providing less insulation than the roof, while the
spandrel sections are even less efficient, showing a U-Value of 1.419 W/m²K (Figure
4.6). This results in thermal comfort and durability issues as walls and spandrels can
become hot to the touch and cause accelerated wear and tear. The windows and
skylights have a U-Value of 1.647 W/m²K, indicating a significant heat transfer through
the glass, along with a Solar Heat Gain Coefficient (SHGC) of 0.21, which means they
do not let in much solar heat. The building lacks blinds, curtains, or shades, which could
impact its thermal comfort and energy efficiency. The heat capacity of the envelope is
set at a medium level of 165,000 J/K, affecting how well the building holds onto heat.
Both the walls and the roof have middle emissivities at 0.5, meaning they release some
of the heat they absorb which causes increased heat absorption during the daytime. This
also means that the building may experience increased thermal lag as it is not able to
release as much heat as it absorbs simultaneously. There’s no ground floor or belowgrade area, so those factors don’t play a role in the thermal performance here. Although
the below-grade U-Value is quite high at 3.293 W/m²K, it does not apply since there
are no below-grade areas in the building. Doors are also left out of this initial model,
making it easier to analyze the building’s thermal performance.

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Figure 4.6. Existing Model Initial Envelope Values
The model takes into account different usage patterns and schedules to evaluate
its energy efficiency in real-world scenarios. However, it doesn't have any daylight or
occupancy sensors, meaning there are no automatic adjustments for lighting or heating
and cooling, based on natural light or how many people are in various spaces. Because
of this, the building operates on a basic setup where lighting and climate controls are
either manually adjusted or set to constant levels. The building's usage patterns and
schedules also show how energy consumption changes with lighting, appliance use,
and temperature settings, and how these elements relate directly to the number of
occupants within a space. Without sensors, energy management is more static and
depends on fixed settings, which might reduce the building's efficiency compared to
those with automated systems.

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For lighting, the building uses 4.84 watts per square meter (W/m²), which shows
the electrical power consumption for lighting in each area, influencing both energy use
and comfort. According to the International Energy Conservation Coede (IECC)
standards, Lagos, Nigeria falls under Lighting Zone 3. Zone 3 typically applies to urban
regions where it is anticipated that lighting levels are moderate or high. Because Lagos
is highly populated, it can be assumed that lighting levels are high. However, due to
the lack of reliable light in the region, Lagos safely falls into Zone 3 as levels could
often be deemed moderate as a result of this. Since the building is categorized in Zone
3, the outdoor lighting is fixed at 750 watts. This level of power usage is on the higher
side and significantly impacts the existing building's overall energy consumption,
especially for nighttime lighting and security purposes.
The power usage for appliances is input at 5.7 W/m², which shows the average
energy consumption of devices per square meter in the building. This covers a range of
gadgets like fridges, computers, and kitchen tools. For people inside of the building,
the metabolic rate is set at 70 METs (Metabolic Equivalent of Task) to mimic standing
activities, which indicates a moderate activity level that adds to the building's internal
heat. This is the most common way to measure how much heat individuals produce
while standing still.
When it comes to heating and cooling, the model has specific targets and
adjustments to keep indoor temperatures in check. The heating target is set at 21°C,
meaning the heating system works to keep the indoor temp at this level when it's

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running. If the outside temperature is more pleasant or conditions shift, the system
drops the temp to 15°C during setbacks, which helps save energy when full heating
isn't necessary. On the flip side, the cooling target is set at 23°C, so the air conditioning
kicks in to keep it at that temp. When cooling isn't as crucial, the system lets the
temperature rise to 29°C, cutting down on energy use during those times. The heating
and cooling systems are designed with specific temperature targets and adjustments to
keep occupants comfortable inside of the building. The heating set-point is set at 21°C,
or 69.8°F, so when the system is turned on, it keep the temperature at that exact same
level. On days where the outdoor weather is more enjoyable, the system drops the
temperature to 15°C, or 59°F, to save energy while heating is not necessary. On the
other hand, the cooling set-point is set at 23°C, or 73.4°F, which means the A/C would
kick in to keep temperatures on the cooler side, assuming that there is one present in
the building. When cooling is not as crucial, the system lets the temperature rise to
29°C, or 84.2°F.
In this case, the model is simulated based on the idea that there is a total of 48
people living inside of the apartment complex, with 8 people in each of the 6 units.
This setup reflects the crowded living conditions often found in Lagos, where homes
typically house more residents than in areas with lower population density. This high
number of occupants affects the internal heat load and energy use since more people
create more heat and contribute to the need for more cooling or heating present in the
building.

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Figure 4.7. Existing Model Usage and Schedule Input Initial Values
Cove.Tool identifies the model’s is set up as one that includes a Dedicated
Outdoor Air System (DOAS) paired with a Water Source Heat Pump (WSHP), along
with a gas boiler and a cooling tower. These arrangements are often designed to
efficiently manage temperature and ventilation while meeting the heating and cooling
demands of the building. The DOAS is the main system used when it comes to handling
outdoor air ventilation, making sure fresh air flows into the building at a consistent rate.
The DOAS works alongside the WSHP, which heats and cools a space by moving heat
to and from a connected water source. The heating efficiency is measured by a
Coefficient of Performance (COP) of 0.82, meaning that for every unit of energy used,
it provides 0.82 units of heat. This COP is low, indicating that the heating system is
nowhere near as efficient as more modern options, which typically have higher COP
values that result in better energy use. The system that the model houses has a COP of

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4. This is a good indication that the system is effective when it comes to cooling down
the atmosphere: for every unit of energy it uses, it delivers 4 units of cooling.
Figure 4.8. 3D Rhinoceros Model of Existing Building
The Cove.tool software indicates that the simulated model uses a central
mechanical ventilation system for both heating and cooling, which means it has a
unified way of handling air flow throughout the space. This system relies on specific
fan power to keep the air moving, helping maintain thermal comfort. The ventilation is

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controlled mechanically with a demand control system that alters the ventilation rates
based on how many people are inside and the air quality at the moment. Each person
gets 2.5 liters of fresh air per second, to ensure everyone has enough to breathe
comfortably. For the building's area, the outdoor air rate is set at 0.2 liters per second
per square meter to synthesize how much air is brought into each part of the building.
The model’s infiltration set point indicates how much outside air is sneaking in through
uncontrolled openings, which can affect the building's energy efficiency and indoor air
quality. It is initially measured at 0.5 cubic meters per hour for every square meter.
The existing building does not have a Building Energy Management System
(BEMS), which aids in controlling and monitoring different systems to make energy
use and operations more efficient. Instead, it depends on manual or basic controls to
manage energy consumption. It is assumed that its domestic hot water (DHW) system
runs on a VR-boiler that heats the building’s water. The hot water distribution is set up
with taps placed within 3 meters of the heat source. This helps reduce heat loss when
delivering hot water to different spots. The total hot water demand for the building is
estimated at 1,330.69 cubic meters per year. For both the cooling and heating systems,
the pump control is set to "All Other Cases," meaning that the pumps work based on
the specific needs of each system rather than following a fixed schedule. This method
ensures that the pumps are used efficiently and are able to adapt to changing demands
throughout the year.

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Figure 4.9. Building System Initial Building System Set Points
4.2 Energy Usage of Structure
To analyze the energy usage for the existing apartment building in Lagos,
Nigeria, with a floor area of 537 m² and an annual Energy Use Intensity (EUI) of 156.18
kWh/m²/year, the total annual energy consumption was first calculated with the
monthly distributed values of energy consumption. The monthly values added up to
result in 83,956.26 kWh annually. The calculation was cross checked by determining
the total annual energy usage, which was derived by multiplying the EUI by the

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building’s floor area. The total annual energy consumption was calculated using the
follow equation:
𝐴𝑛𝑛𝑢𝑎𝑙 𝐸𝑛𝑒𝑟𝑔𝑦 𝑈𝑠𝑒 = 156.18 𝑘𝑊ℎ/𝑚²/𝑦𝑒𝑎𝑟 𝑥 537 𝑚2 = 83,956.26 𝑘𝑊ℎ
Because Lagos, Nigeria, experiences a tropical climate with distinct wet and
dry seasons instead of traditional winter and summer variations, the distribution makes
sense as the energy usage changed in response to the climate that the household may
experience at that time. Energy usage patterns in Lagos tend to show higher
consumption during the hotter months due to increased use of cooling systems and
lower consumption during the rainy season when temperatures are more moderate.
The annual energy usage is distributed monthly and can be seen by the way the
values are closer to one another depending on the specific months that are being
analyzed. Lagos experiences higher energy usage during the hotter, drier months (June,
July, August) and slightly lower energy usages during rainier seasons (March, April,
May, September, October, November).
The calculated monthly energy usage values came out to be (Figure 4.10):
● For winter months (December, January, February): These months are
considered as higher usage periods, similar to the dry season in Lagos, with
an average of 7,614.31 kWh per month or 14.21 kWh/m².
● For spring and fall (March, April, May, September, October, November):
These months reflect moderate energy usage due to the milder temperatures,
with an average of 6,106.79 kWh per month or 11.37 kWh/m².

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● For summer months (June, July, August): These months, similar to the
hottest period in Lagos, show a higher energy usage of 8,256.71 kWh per
month or 15.37 kWh/m².
Figure 4.10. Monthly Energy Usage of Actual Existing Structure
4.2.1 Energy Usage of Baseline Model
Using Cove.Tool’s grasshopper plug in (Figure 4.11) and energy modeling
scripts, the energy usage of the simulated model was set up and cross-checked to ensure
that values were identical to the existing model’s actual values prior to the simulation
process. The address of the apartment complex was put into the Cove.Tool website.
Because Lagos does not follow a set local energy code, ASHRAE - 2019 IECC 2021

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Equivalent was used as a baseline for the simulations (Figure 4.12). This was done to
ensure that, in both cases, calculations were made from the same baseline or starting
point. When the simulated model accurately mirrors the real model’s energy usage data
from the existing model, any differences that pop up during the simulation can be linked
to the new design parameters or simulation settings instead of issues with the initial
data. This verification process acts as a quality check. This step reduces the chance of
mistakes and enhances the reliability of the predictions from the simulation, which is
important for making rational choices about the energy conservation methods and
design improvements.
The baseline model does not use renewable energy features. It doesn't have any
photovoltaic (PV) solar panels or solar hot water (SHW) collectors installed (Figure
4.13). The simulated model also indicates these outcomes. With a solar panel area of 0
square meters, the building is not using solar energy for electricity in any case. This
means it depends completely on traditional energy sources like grid electricity to
function.
In the case that solar panels were present in the existing model, the solar panels
would be set to lie flat at a 0-degree angle, which is not the best option for capturing
sunlight. The building also lacks SHW collectors, with a surface area of 0 square
meters, meaning that it does not use solar thermal energy for heating water. If there
were SHW collectors, they would convert solar energy into heat for hot water, and also
be placed a a 0-degree angle. Hypothetically, they would have a thermal efficiency of

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50% in the case that they were present in the model. This percentage is decent under
perfect conditions. Because there are no collectors present in the building, this
efficiency doesn’t play a role in the building’s energy use.

Figure 4.11. Cove.Tool Grasshopper Script for Simulated Model

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Figure 4.12. Cove.Tool Address Input and Energy Code for Simulated Model
Figure 4.13. Solar Energy General Initial Inputs
While the baseline model’s EUI was also 156.18 kWh/m² per year, this is not
enough to hit ZNE goals in the near future or the proposed benchmark goal for 2030.
These results align with other research on Nigerian homes, where high thermal mass
and inadequate insulation often lead to overheating, pushing up cooling energy
demands, especially in the hotter months. Plus, the frequent power outages force many
to rely on diesel generators, which only adds to the energy consumption and lowers the
overall efficiency of these homes. The building’s walk score, according to Cove.tool’s
analysis is a 56 out of 100, making the surround area somewhat walkable but on the
lower end. This means that some errands can be accomplished on foot, but it is advised
against.

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Figure 4.14 Energy Model of Initial Building with BREPS
The building's initial Energy Use Intensity (EUI) is divided into several
categories that highlight the specific energy needs for different systems. Cooling stands
out as the biggest factor at 51.93 kWh/m²/year, which is evident in a tropical place like
Lagos, Nigeria, where the heat requires constant cooling for thermal comfort. This high
demand for cooling indicates that enhancing thermal insulation, opting for reflective

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roofing, or adjusting the building's orientation could help lower energy consumption.
Heating shows a contribution of 0 kWh/m²/year, which is typical for warmer climates
where space heating is not necessary. As mentioned earlier, though residents do have
access to air conditioning, most do not use it due to unreliable electricity and its low
usefulness when temperatures are warmer. Energy modeling varies by location.
Buildings in colder areas would have higher heating EUI values. The apartments’
lighting accounts for 15.75 kWh/m²/year, representing the energy used by artificial
lighting. Given Lagos' abundant natural sunlight, implementing daylighting techniques
and using passive, energy-efficient lighting like modifications in window placements
and sizes could reduce this figure significantly. The equipment load is currently at
35.99 kWh/m²/year which makes up a significant part of the EUI, driven by appliances,
office gear, and tenant-specific electronics. To lower this demand, using energyefficient appliances and promoting energy-saving habits among occupants would be
key. Occupant behavioral strategies would be best when it comes to contributing to the
reduction of this category, therefore, in this study, it is not anticipated that this value
will decrease as simulations are ran. Lastly, fans use 27.53 kWh/m²/year, which
highlights the energy needed for ventilation systems that keep the air circulating in the
building. Incorporating successful cross-ventilation would cut down on energy use in
this category. Pumps contribute a small amount of 2.19 kWh/m²/year to the energy
usage and are responsible for circulating water for cooling, heating, or everyday needs.
Even though this load is on the lighter side, switching to more efficient pump systems
can still lead to energy savings. However, this value is expected to stay the same as the
study focuses primarily on passive energy conservation methods. The building’s hot

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water usage hits 22.8 kWh/m²/year. The represents how much energy is needed to heat
and distribute water into the building. Cooling and equipment contribute the most when
it comes to energy consumption in the apartment, so tackling these areas—by
modifying building design, envelope, and materials selection—would cut down the
building’s overall energy consumption.
Figure 4.15. EUI Breakdown of Existing Baseline Model
Existing Building’s Energy Usage by Percentage

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Figure 4.16. Energy Usage Percentage Categories of Existing Simulated Model
4.3 Energy Conservation Methods
Based on the interviews and the base case study, energy conservation methods
(ECMS) were chosen. The choices primarily depended on what characteristics of the
building could be improved to achieve thermal comfort for occupants and what could
be incorporated to the structure to improve performance. This section goes over the
chosen ECMs and why they were chosen to cut down on energy use, boost comfort for
residents, and support sustainability. These methods address major concerns such as
cooling needs and heavy dependence on artificial lighting in the city. All of the chosen
ECMs were passive design options that provide room for expansion if necessary in the
future. The ECMs are categorized into three major components: Building Orientation

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and Design, High-Performance Building Envelope, and Materials Selection. The ECMs
include modifications like ‘L-shaped’ windows that help with natural ventilation and
daylight, as well as shading devices and overhangs/balconies that are essential for
harnessing natural energy.
The study showed that the size of windows and the orientation of the building
are also key factors in saving energy and improving the building’s overall performance.
When window sizes were made smaller on the East-West-facing windows, heat gain
was limied from the morning sun, while adjusting the building's position to maximize
natural daylight cut down on the need for artificial lighting by increasing natural
lighting. Repositioning the building to minimize heat gain focuses on orienting it to
reduce direct sunlight exposure, which further lowers cooling demands especially
during Lagos’ hotter times of the year.
Upgrading the apartment complex’s building envelope with modified insulation
and high-performance windows also plays a crucial role in keeping indoor temperatures
steady by stopping unwanted heat flows. It is safe to say that these updates alone play
a huge role in improving performance and expanding overall comfort. Choosing
sustainable materials that have high thermal mass helps with energy efficiency by
soaking up and releasing heat when necessary, which regulates indoor temperature
changes. Together, these energy conservation lead to lasting energy savings and a
smaller environmental footprint in Lagos, Nigeria.

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Figure 4.17. Energy Conservation Methods and Their Final Outcomes
4.4 Building Orientation and Form
The building’s orientation and design plays a keep role in energy efficiency and
occupant, especially in tough climates like Lagos, Nigeria. The way that a building
faces the sun and wind directly affects how much heating, cooling, and lighting it needs.
If the orientation is thought about during the design process, they can use natural
conditions to cut down on energy use. For example, aligning the longest sides of a
building with the north-south direction helps limit direct sunlight on the east and west
sides, where the sun’s effects are most dominant in the morning and late afternoon.
Using design techniques that encourage cross-ventilation to optimize natural
light is another alternative to saving energy. By positioning windows to allow airflow,
buildings remain cool without the need of active mechanical systems. Smart
daylighting choices, such as placing more windows on the north and south sides of the
building and fewer on the east and west, decreases the need for artificial lighting, which

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saves energy and makes the indoor space more comfortable. Adding shading devices,
overhangs, and balconies to the existing design can further help reduce solar heat gain.
Precise solar orientation is important for contributing to a better energy
performance outcome. When orienting a building, it is important to take note of how it
may interact with the sunlight during the day. When a building is aligned and oriented
properly, and has effective shading and ventilation options, it can capture solar energy
and block it when it is not needed, which helps lower overall energy use and boosts
sustainability.
Optimizing solar orientation is a critical strategy in energy-efficient building
design, particularly in regions with strong seasonal climate variations or high solar
exposure, like Lagos, Nigeria. By carefully aligning buildings relative to the sun’s path,
energy loads associated with artificial lighting, heating, and cooling, that contribute to
higher EUIs, can be reduced. The goal of optimizing solar orientation is to balance the
benefits of natural daylight during colder seasons with the need to minimize solar heat
gain during periods of higher temperatures. This dual focus on daylight optimization
and heat reduction allows buildings to be more sustainable. In Lagos, where the climate
remains predominantly warm year-round, the main design focus is on maximizing
daylight and minimizing heat gain, particularly during the hottest periods of the year.
The simulation findings underline the importance of proper building orientation
in regarding to reducing energy use. The overall results show that optimizing the
alignment of a building’s longest sides along the north-south axis significantly lowers

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heat gain on the east and west facades, where solar exposure is most intense. This
reduces cooling loads, leading to a lower overall energy usage index (EUI).
Incorporating these findings into the design process ensures that buildings can operate
more efficiently, saving energy, improving comfort, and reducing overall costs.
4.4.1 Reposition of Building - Maximize Natural Daylight
Maximizing natural daylight is often a primary goal when it comes to the design
of energy-efficient buildings. Prior to the simulation being ran, the model was
positioned to have the main windows of the building facing south. This was done by
rotating the building so that the East and West now substitute themselves for the
positions of the North and South. In other words, the building was rotate ninety degrees.
While Lagos does not experience a traditional winter like more temperate climates, the
slight temperature fluctuations and shorter daylight hours during this period make
optimizing natural light a key factor in reducing reliance on artificial lighting and
overall energy consumption in the region.
The results of this simulation reveal that buildings designed with an emphasis
on maximizing natural daylight during the winter months can achieve notable energy
savings. The simulation results showed that this strategy could lead to anywhere from
5% to 10% reduction in overall energy use intensity (EUI), bringing the building’s EUI
down to 148.88 kWh/m² from an initial value of 156 kWh/m²/year. This reduction is
achieved primarily through improved natural lighting efficiency, where increased

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daylighting almost eliminates the need for artificial lighting during daytime hours. The
study showed that the use of larger south-facing windows, coupled with reflective
surfaces and light shelves, allowed for better daylight distribution, particularly in
deeper interior spaces such as central hallways or corridors.
Despite this slight reduction, the strategy did not contribute to additional LEED
points, with the EAc2 Credit remaining at 0. However, the environmental impact of the
reduction in energy consumption was evident, with a 10% reduction in CO2 emissions.
This not only contributes to a lower carbon footprint but also improves the
sustainability profile of the building. From a financial standpoint, the reduced reliance
on artificial lighting led to a decrease in electricity costs, with annual expenses
projected at ₦38,065,543.01, or $27,141.14. while gas costs remained consistent at
₦3,445,983.47, or $2,097.63, annually.
The detailed EUI breakdown of the building’s energy consumption supports
these results. Lighting energy consumption was optimized at 14.8 kWh/m²,
demonstrating that the increased natural daylight significantly reduced the demand for
electric lighting. However, one challenge associated with this strategy was the
corresponding increase in cooling energy consumption, which rose to 43.65 kWh/m²
from its original baseline value. This increase was due to the additional solar heat gain
from the larger windows, resulting in the need for more active cooling to maintain
comfortable indoor temperatures. While the intention was to reduce energy usage, the
increase in cooling energy highlights the trade-off that must be managed when
optimizing natural light in tropical climates, where solar heat gain is often a concern.

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The fan energy consumption increased to 23.14 kWh/m², reflecting the higher
ventilation requirements to address the excess heat from solar gain. This means that it
is importance to integrate passive cooling techniques, such as shading devices and
ventilation strategies, to counterbalance the effects of solar heat gain while still
benefiting from natural daylight. Pumps and hot water consumption remained stable at
2.19 kWh/m² and 22.8 kWh/m², respectively. This is due to the fact that the pump and
hot water systems were not directly impacted by the daylighting strategy.
The benefits of maximizing natural daylight are most noticeable during the
winter months in Lagos. While this technique resulted in a 5%-10% reduction in overall
EUI, lowering it to 148.88 kWh/m², it did not yield additional LEED points. Overall, it
contributed to a 10% reduction in CO2 emissions and reduced electricity costs.
Figure 4.18. Proposed EUI after Maximizing Natural Daylight

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4.4.2 Reposition of Building - Minimize Heat Gain
Lagos’ hot climate makes minimizing heat gain during the summer months an
another important aspect of optimizing solar orientation. In fact, reducing heat gain
becomes a main priority for efficient building design in densely populated, tropical
regions Lagos as cooling loads usually remain higher year-round.
The results of the simulation revealed that minimizing heat gain through proper
building orientation and shading can reduce cooling loads by up to 30%. The findings
indicate that by limiting windows on the east and west facades, buildings can
significantly reduce the amount of direct sunlight entering during the morning and
afternoon, which are the peak heat-gain periods. This strategic reduction in solar
exposure resulted in lowering indoor temperatures by up to 3°C. This directly
minimizes the need for air conditioning units in the building.
Shading devices, overhangs, and balconies were found to be particularly
effective in blocking direct sunlight and are a popular staple in most single-family
Nigerian homes today. South-facing overhangs, designed to provide shading during
high summer sun angles, reduced heat gain by as much as 20% on the south facade.
Vertical shading devices on the east and west facades reduced low-angle solar radiation
by about 15%, further decreasing the building’s reliance on mechanical cooling
systems. Additionally, the simulation showed that high-performance glazing was found
to reduce solar heat gain through windows by up to 30%, providing even further
reductions in the building’s cooling energy demand.

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The results from the study show that these energy conservation methods,
especially when combined, can significantly lower a building’s cooling load, reducing
the overall EUI annually. By minimizing heat gain, buildings can achieve greater
energy efficiency, making them more cost-effective to operate while improving
comfort for occupants during the unbearably warmer periods of the year. See section
4.4.3d - Window Sizing on Warm Sides (East and West) for simulation outcomes.
4.4.3 Form
Compacting the building shape is another ECM that can help improve the
building’s performance. A more compact building form reduces the surface area that is
exposed to the apartments’ surrounding environment, limiting the amount of heat gain
or loss. This outcome minimizes the energy required for cooling or heating. This
section explores the relationship between building shape and energy performance,
focusing on how changes in surface area, floor plan, and building configuration affect
a building’s overall energy efficiency. The building will then be simulated to the most
effective energy conservation method (ECM) of the section and outcomes will be
analyzed (See Chapter 5).
In a study designed to analyze the energy performance of different building
forms, several scenarios were tested using a simple box model. The study compared
outcomes for three key variations or potential ECMs: (1) adding stories to a building
while maintaining the same floor area, (2) splitting a single building into two separate
structures of the same total size, and (3) altering the building's shape to increase or
decrease its surface area-to-volume ratio. Each of these scenarios provided important

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insights into how compacting or altering the building’s shape can influence its overall
energy performance.
Surface area and floor plan are directly linked to the thermal performance of a
building. The surface area exposed to external conditions, particularly solar radiation
and ambient air temperatures, determines how much heat can enter or escape the
building. The larger the surface area is in relation to the building’s volume, the more
the building will be affected by external temperature changes, which increases the
demand for the broken down EUI categories, especially heating and cooling, to keep
comfortable indoor conditions. Therefore, keeping the building shape more compact
and reducing the exposed surface area are beneficial ECMs for saving energy.
Scenario 1: Adding Stories to the Building
The first scenario in the box model analysis involved adding additional stories
to a building without changing the overall floor area. This vertical design change has
been shown to significantly improve energy performance because it reduces the ratio
of surface area to volume. For example, a two-story building with a floor area of 1,000
square meters has a much higher surface area-to-volume ratio than a five-story building
with the same floor area. By stacking the floors, the overall external surface area
decreases, limiting the exposure to heat gain from the sun and reducing cooling energy
demand.
The results found that increasing the number of stories reduced the overall
energy use intensity (EUI) of the building by up to 15%. The key reason for this

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improvement is that the internal floors share walls with adjacent stories, reducing the
number of external walls exposed to the environment. Taller buildings benefit from a
reduced roof area, which is often a significant source of heat gain in tropical climates
like Lagos’. The reduction in surface area also reduces the building’s exposure to solar
radiation and external air temperatures, which is particularly beneficial in minimizing
EUI loads.
Scenario 2: Splitting a Building into Two Separate Buildings
In the second example, the analysis of the box model considered the energy
performance of splitting a single large building into two smaller buildings of the same
total floor area. This approach increases the surface area-to-volume ratio because the
two buildings have more exterior walls exposed to the outside environment compared
to a single, compact structure. The findings showed that splitting the building
approximately resulted in a 10% increase in energy consumption, primarily due to the
amount of increased surface area exposed to external heat gain.
The study highlighted that each of the two smaller buildings required more
energy for cooling because they experienced a higher amount of exposure to solar
radiation. In the existing building, adding additional surface area would mean that more
heat would the building, increasing EUI loads. As a result, it is safe to say that
compacting the building’s form is the better alternative to minimize energy use. The
findings suggest that for optimal energy performance, buildings in Lagos should be
designed to remain as a single, compact structure rather than being split into multiple
smaller ones for design purposes.

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Scenario 3: Changing the Building Shape
The third scenario focused on changing the shape of the building while keeping
the overall floor area constant. By altering the building's form to create more complex
shapes with more external walls, the surface area increases, leading to higher energy
consumption. In this case, a box model was modified from a rectangle into an L-shaped
building. A rectangular building has a more compact form than an L-shaped or Ushaped building of the same floor area. The study revealed that more complex shapes
resulted in anywhere from 5-15% increase in energy consumption because there is a
larger amount of surface area that is exposed to external conditions.
The box model study revealed that compact shapes are more energy-efficient
because they minimize the number of external surfaces that are in contact with the
outside environment. In contrast, more complex and uncommon shapes with additional
corners and facades increased heat gain and cooling demand. This is what causes EUIs
to fluctuate or increase as well. In Lagos, compact and regular building forms are more
effective at maintaining energy performance and keeping the buildings initial structure.
The study found that rectangular buildings with a high floor-area-to-surface-area ratio
performed the best in terms of energy efficiency.
4.5 Passive Solar Design
Passive solar design is an essential strategy for improving energy
efficiency in buildings where high solar radiation dominate throughout the year and is
another option that reducing the need to mechanical systems. This section focuses on
several key passive solar design strategies—L-shaped windows, overhangs, shading

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devices, and window sizing on the warm sides (east and west)—that were explored in
the study. These strategies harness natural energy to reduce the building’s energy use
intensity (EUI) and are a perfect fit for building design in Lagos when mechanical
systems are not always present.
4.5.1 Window Sizing on Warm Sides (East)
Window sizing on warmer sides, primarily the east and west facades, played a
huge role in cutting down heat gain. By making the windows smaller on the east and
west sides, heat is regulated throughout the building and residents can take advantage
of daylight. This results of this simulation proved that smaller windows on the east and
west facades, or warmer sides, impact the building's EUI in a positive way.
In section 4.4.2–Minimizing Heat Gain, we talked about the energy-saving
technique of adjusting window sizes on certain sides. After running the simulation, the
proposed baseline Energy Use Intensity (EUI) for using smaller windows on the east
and west sides came out to be 139.16 kWh/m², which is a solid drop from the original
EUI of 156 kWh/m²/year. This 10.8% reduction improved the existing building’s
performance immensely.
The initial EUI breakdown shows that the cooling load decreased to 37.29
kWh/m², a significant improvement in comparison to the higher levels of heat gain
experienced with larger windows that were initially installed in the building. By
minimizing the window size on the east and west sides, the building absorbs less direct
sunlight during the hottest hours. This technique would work effectively in collaboration

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with the other energy conservation methods, as it specifically targets heat gain from the
most problematic orientations in terms of solar exposure.
After the simulation was ran, the building’s lighting energy use stayed at 14.8
kWh/m², as the reduced window size did not significantly interfere with natural
daylight. This balance between window sizing and natural light ensures that the
building can still rely on daylighting strategies during daylight hours and not entirely
black the building out.
The energy use for equipment, fans, and pumps is similarly affected. Equipment
energy remains at 42.31 kWh/m², consistent with the other energy conservation
methods, while fan energy consumption slightly increased to 19.77 kWh/m², reflecting
the need for enhanced ventilation to offset any potential discomfort that may be caused
by the smaller windows. Pumps and hot water energy usage are unchanged at 2.19
kWh/m² and 22.8 kWh/m², respectively.
Figure 4.19. Proposed EUI with East-West Window Sizing

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4.5.2 L-Shaped Windows
L-shaped windows enhance natural lighting and ventilation. By wrapping
windows around building corners, this design strategy increases daylight penetration
from multiple angles, reducing reliance on artificial lighting and improving indoor
environmental quality. The findings from the simulation reveal key performance
outcomes associated with the use of L-shaped windows.
The proposed whole baseline Energy Use Intensity (EUI) for a building
incorporating L-shaped windows was calculated at 131.18 kWh/m² (Figure 4.21), a
significant improvement compared to the building’s initial EUI value of 156
kWh/m²/year. This represents a reduction of 24.82 kWh/m², or approximately a 16%
improvement in energy efficiency. The inclusion of L-shaped windows not only
optimizes energy performance but also contributes to a 21% reduction in CO2
emissions, which aligns with Lagos’s energy efficiency goals for reducing the carbon
footprint of buildings as it is a heavily populated city that experiences a lot of pollution.
Although the LEED Points for the EAc2 Credit remained at zero, the significant
reduction in energy usage and environmental impact demonstrates the value of
incorporating L-shaped windows into the existing building’s design, even in areas
where official certifications may not yet recognize these modifications. It is important
to note tha Lagos, and many neighboring countries, are a bit behind when it comes to
designing for sustainability. Because of this, while this outcome of incorporating Lshaped windows may not seem beneficial to many parts of the world, it is a big step
toward achieving the 2030 goal.

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In terms of cost efficiency, the findings revealed that the use of L-shaped
windows resulted in annual electricity costs of ₦32,723,522.8, or $19,949.47 and gas
costs of ₦3,445,983.4, or $2,100.80. This reduction in energy consumption is
especially significant in Lagos, where energy costs are high, and efficient resource use
is vital. The walkability score remained at 56, indicating there is still moderate
accessibility to essential amenities, highlighting that the building’s location and design
promote sustainable urban living.
Breaking down the initial EUI values provides further insight into the energy
performance of the building. The cooling load, at 32.08 kWh/m², represents a major
portion of the building’s energy consumption. L-shaped windows, by improving
natural ventilation and effective daylight penetration in spaces, help mitigate this
cooling load. Lighting energy usage, at 14.8 kWh/m², is significantly reduced thanks
to the daylighting benefits of the new windows, as natural light reduces the need for
artificial lighting during daylight hours.
Additionally, equipment energy consumption is 42.31 kWh/m², and fans use
17.01 kWh/m², both of which are optimized by the improved air circulation facilitated
by the window design. Hot water energy consumption remains steady at 22.8 kWh/m²,
which is consistent with other the passive solar design strategies.
Overall, the implementation of L-shaped windows not only improves the
energy performance of the building but also enhances occupant comfort by increasing
natural light and ventilation. The 16% reduction in EUI compared to the initial value
of 156 kWh/m²/year highlights the effectiveness of this design strategy. The 21%

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reduction in CO2 emissions further reflects the building’s improved sustainability
profile, while the cost savings in electricity and gas underline the economic benefits of
adopting this energy-efficient design.
Figure 4.20. Location of L-Shaped Windows and Energy Modeling BREPS
Figure 4.21. Proposed EUI after L-Shaped Windows
4.5.3 Shading Devices
Shading devices, such as louvers, awnings, and external blinds, are designed to
block direct sunlight from entering the building while still allowing for natural light.

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This reduces solar heat gain, lowers the need for mechanical cooling, and contributes
to overall energy efficiency. The analysis of shading devices in this study revealed
important improvements in the building’s energy performance. As mentioned earlier,
the values of the existing U-Values, SHGC, and lighting coefficients were not altered
(Figure 4.22). The spandrel and glazing u-values are 1.419 W/m²K and 1.647 W/m²K
respectively. The skylight u-value of the existing building is 1.647 W/m²K. The SHGC
for glazing and skylight are set at 0.21. The skylight u-value The buildings envelop
heat capacity level is set to a medium value of 165,000. The ‘Blinds/Curtains/Shades’
input was toggled change and set to ‘(Exterior) Blinds’ before the simulation is ran
(Figure 4.22).
Figure 4.22. New U-Values after Shading Devices are added to Simulated Model
The proposed whole baseline Energy Use Intensity (EUI) for a building with
shading devices was calculated at 127.93 kWh/m², a marked improvement compared
to the building’s initial EUI value of 156 kWh/m²/year. This represents a 28.07 kWh/m²
reduction, or approximately an 18% improvement in energy efficiency. Although

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shading devices did not earn any additional LEED points (with the EAc2 Credit
remaining at 0), they still provided substantial energy and cost savings, particularly in
cooling and lighting systems.
The implementation of shading devices led to a 23% reduction in CO2
emissions, underscoring the environmental benefits of this energy conservation
method. In terms of operating costs, annual electricity expenses were reduced to
₦31,742,211.14, with gas costs remaining stable at ₦3,445,983.4. These savings,
particularly in electricity, highlight how shading devices can alleviate the financial
burden of energy use in a climate like Lagos’s, where high cooling demands dominate
much of the year.
Breaking down the initial EUI values provides more specific insights into the
areas of energy consumption improved by shading devices. The cooling load decreased
to 29.96 kWh/m², showing how shading prevents excessive solar radiation from
penetrating the building envelope. This reduction in heat gain directly translates into
lower cooling energy use, which is critical in maintaining comfortable indoor
temperatures without over-reliance on air conditioning. Shading devices, while
effective in reducing heat gain, still allow sufficient natural light to enter the building.
As a result, lighting energy consumption remains at 14.8 kWh/m², indicating a balance
between daylight and artificial lighting use.
The energy consumption for equipment remains at 42.31 kWh/m², similar to
other passive solar design strategies. This shows that shading devices primarily benefit
systems related to temperature and sunlight management, such as cooling and lighting.

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Fan energy consumption is also slightly reduced, at 15.88 kWh/m², as the need for
enhanced air circulation is mitigated by the reduced heat gain. The pumps and hot water
energy consumption stay constant at 2.19 kWh/m² and 22.8 kWh/m², respectively, as
these systems are less influenced by shading devices.
Adding shading devices to the building cuts the energy use intensity (EUI)
down by 18% from the original 156 kWh/m²/year to 127.93 kWh/m², and contributes
to a 23% drop in CO2 emissions. While these shading devices didn’t rack up any LEED
points, they still offer great energy and cost savings, especially when it comes to
lowering cooling demands. In Lagos's hot climate, these devices are a smart choice for
keeping solar heat gain in check and designing energy-efficient buildings.

Figure 4.23 Simulated Model with Addition of Shading Devices

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Figure 4.24. Proposed EUI with Shading Devices
4.5.4 Overhangs
Overhangs are an essential passive solar design feature that significantly
contributes to energy efficiency by controlling solar heat gain and improving overall
building performance. In regions like Lagos, where high temperatures are common,
overhangs help harness natural energy by shading windows from direct sunlight,
particularly during the hottest parts of the day. They also remain a staple piece to singlefamily, Nigerian home design presently though are not as common in urban housing
design yet. The findings of this simulation demonstrate how overhangs, when designed
properly, harness natural energy and protect buildings from excessive heat gain, leading
to a considerable improvement in energy performance. It also shows how simply
overhangs can be incorporated into the building’s design (Figure 4.24).

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Figure 4.25 Energy Model of Existing Building with Use of Overhangs
The proposed whole baseline Energy Use Intensity (EUI) for a building
incorporating overhangs was calculated at 122.75 kWh/m², a notable reduction from
the building's initial EUI value of 156 kWh/m²/year: a 21.3% improvement. The
incorporation of overhangs resulted in a 26% reduction in CO2 emissions, contributing
to the building’s overall sustainability. This design strategy also earned 2 LEED points
under the EAc2 Credit system, marking a tangible achievement in green building
performance. The initial EUI breakdown shows that overhangs greatly reduce the
cooling load to 28.99 kWh/m², down from the higher levels seen in buildings without
this passive ECMs. By controlling the amount of direct sunlight entering the building,
overhangs lessen the need for air conditioning, which is a major characteristic as half
of the homes in the area do not have air conditioning installed already (see Figure 4.5).
Lighting energy consumption is also positively impacted, with the building using 11.09
kWh/m² for lighting needs. The incorporation of overhangs did not interfere with

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natural daylighting, allowing for adequate light while reducing the reliance on artificial
sources.
The equipment energy use remains at 42.31 kWh/m², showing that overhangs
primarily benefit systems directly influenced by temperature regulation, such as
cooling and ventilation. Fan energy use is 15.37 kWh/m², slightly reduced due to the
lowered cooling demand, while pumps maintain a constant consumption of 2.19
kWh/m². Hot water energy use stays steady at 22.8 kWh/m², unaffected by the
implementation of overhangs.
In conclusion, the use of overhangs to harness natural energy results in a
significant enhancement in energy performance, with a 21.3% improvement over the
building's initial EUI value of 156 kWh/m²/year. By reducing cooling loads and
improving overall energy efficiency, overhangs not only lead to a 26% CO2 reduction
but also generate substantial cost savings in electricity. This passive design strategy
effectively manages Lagos's challenging climate conditions, making it an essential
component of sustainable building design in the region.
Figure 4.26. Proposed EUI with Overhangs

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4.6 High-Performance Building Envelope
The combination of advanced insulation techniques and high-performance
window systems improve the performing of the existing structure’s building envelope
resulted in significant energy savings and improved building performance. The
proposed upgrades reduced the building’s EUI to 113.64 kWh/m²/year, a notable
improvement from the initial value of 156 kWh/m²/year, representing more than a 27%
overall reduction in energy usage. Cooling energy consumption saw the most
substantial decline, dropping by over 50% due to the enhanced insulation and glazing
systems that effectively minimized heat gain.
In terms of environmental impact, the building achieved a 31% reduction in
CO2 emissions. The financial benefits were equally compelling, with significant
reductions in electricity costs, further justifying the investment in high-performance
building envelope solutions.
The use of Extruded Polystrene (XPS) insulation and Exterior Insulation and
Finishing (EIFS) systems for the roof and walls, alongside double glazing with Low-E
coatings, were incorporated into the simulated model.

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Figure 4.27. Proposed EUI with Modified Insulation
4.6.1 Material Selection
In the pursuit of energy efficiency and sustainability, the selection of
appropriate materials is essential. In tropical climates such as Lagos, Nigeria, material
choices must not only meet aesthetic and functional requirements but also address the
unique challenges posed by the local environment. This section dives into the impact
of using sustainable materials and thermal mass materials, specifically tailored to the
conditions in Lagos, and discusses the findings derived from simulations using
Cove.Tool’s Assembly Builder to analyze the chosen materials.
4.6.1a Sustainable Materials
In Lagos, sustainable materials that are well-suited to the local climate can
significantly improve overall building performance. The Cove.Tool Assembly Builder
was utilized to explore different material options and their impacts on energy use. This

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tool allows for the detailed modification and analysis of building assemblies to
understand how various materials influence overall energy performance.
For Lagos, materials like locally sourced clay bricks, ventilated facades, and
roofing materials with high reflectance are effective choices. Clay bricks, due to their
thermal mass, help moderate indoor temperatures by absorbing and slowly releasing
heat. Ventilated facades allow for improved air circulation while high-reflectance
roofing materials help mitigate solar heat gain, contributing to lower EUI distribution
as a whole.
4.6.1b Thermal Mass Materials
In Lagos, materials with high thermal mass can help stabilize indoor
temperatures. Materials such as concrete with high density and compressed earth
blocks were evaluated using Cove.Tool’s Assembly Builder. The Assembly Builder
allows for the simulation of different material assemblies, providing insights into their
thermal performance and impact on overall energy use. By incorporating materials with
high thermal mass, such as concrete or earth blocks to the Assembly Builder, the
building's energy performance can be optimized by leveraging their ability to regulate
indoor temperatures effectively.
Thermal Mass Placement
Effective placement of thermal mass within the building envelope is essential
for maximizing its benefits. Strategic placement can enhance the thermal performance

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of the building, making it cooler during hot periods and warmer during cooler periods.
In Lagos, optimal placement involves using thermal mass in areas that are exposed to
direct sunlight during the day, such as external walls and roof spaces. The model was
adjusted to move interior walls within each unit, changing the building’s thermal mass
distribution.
The simulation results revealed that incorporating thermal mass into the
building design, especially on the exterior walls and roof, significantly improved
energy performance. The results indicated a proposed EUI of 123.59 kWh/m²/year.
This approach contributed to a more stable indoor environment, approving comfort for
the occupants. The CO2 reduction was 25%, reflecting the effectiveness of thermal
mass in moderating temperature fluctuations and lowering monthly energy usage.
The Cove.Tool Assembly Builder’s simulation provided a detailed analysis and
optimization of material placement and types. The tool provided valuable insights into
how different materials and their configurations impact energy performance, enabling
informed decision-making for sustainable building design.
Figure 4.28. Proposed EUI with New Materials Selection

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4.6.2 Modified Insulation
Incorporating high-performance insulation is one of the most effective
strategies for reducing energy consumption in buildings, particularly in tropical
climates like Lagos, Nigeria. Insulation plays a critical role in managing heat transfer
between the interior and exterior of a building, which can have a profound impact on
energy usage, especially in a region with high temperatures and humidity. This section
examines the impact of enhancing the insulation properties of the building envelope,
focusing on materials such as extruded polystyrene (XPS) for roofs and walls, and
external insulation and finish systems (EIFS).
Insulation Materials and Design Choices
For the roof insulation, the thickness of extruded polystyrene (XPS) was
increased to anywhere from 150mm to 200mm. XPS is a preferred material in Lagos’
because of its moisture resistance and durability. Since Lagos experiences a significant
amount of rainfall and humidity, moisture-resistant materials are essential to prevent
mold and material degrading over time. Increasing the thickness enhances the
insulation capacity, thus reducing the amount of heat that penetrates into the building.
The wall insulation, expanded or extruded polystyrene (XPS), with a thickness
ranging from 250mm to 400mm is the most recommended. This insulation strategy was
selected for its cost-effectiveness, light weight, and widespread usage and accessibility
in Lagos, making it both practical and efficient. The use of an External Insulation and
Render System (EIFS) helps to further protect the walls from external heat while

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allowing for moisture control. The incorporation of this system creates a thermal barrier
that helps stabilize the internal temperature of the building.
Findings
The proposed insulation upgrades resulted in a significant reduction in energy
consumption. The proposed whole baseline Energy Use Intensity (EUI) for the building
was 113.64 kWh/m²/year, compared to the initial EUI of 156 kWh/m²/year, marking a
substantial improvement. The high-performance insulation system led to a cooling
energy consumption reduction, with the cooling load dropping from 51.93 kWh/m² to
24.12 kWh/m². Furthermore, the insulation improvements contributed to a 29%
reduction in CO2 emissions, emphasizing the environmental benefits of this strategy.
With fewer cooling requirements, the building’s reliance on electricity decreased,
resulting in an annual savings of ₦38,065,543.01, or $23,206.17, in electricity costs.
4.6.3 High-Performance Fenestration
Window types are another component of a successful building envelope,
significantly affecting both thermal comfort and energy performance. In many parts of
Nigeria, the choice of window glazing can have a direct impact on the building’s
cooling load and overall energy usage. This simulation explores the benefits of
incorporating high-performance windows with Low-E (low emissivity) coatings and
double glazing to improve insulation and reduce solar heat gain.
Window Glazing System

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The proposed glazing system consists of two panes of glass separated by a space
filled with argon or air, with a Low-E coating applied to one or both surfaces. This
system is designed to reduce solar heat gain while improving insulation, making it ideal
for tropical climates, where the primary concern is minimizing the amount of heat that
enters the building.
Double glazing with Low-E coatings typically achieves U-values around 1.3
W/m²K, making it suitable for this study’s requirements. Low-E coatings help reflect
infrared light, preventing heat from entering the building during the day, while still
allowing visible light to pass through. This ECM, as well as many of the previous ones,
reduce the need for artificial lighting during the day and decreases the cooling load by
limiting the amount of heat that needs to be fought against by air conditioning or
renewable energy sources.
Findings
The integration of high-performance windows in this project demonstrated a
significant reduction in overall energy consumption. The proposed whole baseline EUI
was reduced to 112.17 kWh/m²/year, a considerable improvement from the initial EUI
of 156 kWh/m²/year. In particular, cooling energy consumption dropped to 23.17
kWh/m², reflecting the impact of reduced solar heat gain. The Low-E coatings and
double glazing were also proven to be effective in minimizing the amount of heat
entering the building.
In terms of carbon emissions, the use of high-performance windows contributed
to a 30% reduction in CO2 emissions. After the envelope was modified, the roof’s u-

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value decreased from the building’s initial value of 0.255 W/m²K to 0.2 W/m²K. The
wall u-value also decreased from 0.566 W/m²K to 0.07 W/m²K while the glazing uvalue had a slight decrease from 1.647 W/m²K to 1.312 W/m²K.
Figure 4.29 Proposed U-Values after Simulations

Figure 4.30. Proposed EUI Outcomes after Simulating ECMs

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4.7 Summary
Chapter 4 focused on analyzing the existing case study, the modeling of the
existing case study, its energy usage, and energy conservation methods: building and
form, passive solar design, and high-performance building envelope. After testing the
energy conservation methods, it was determined that the incorporation of a highperformance building envelope was the most beneficial in decreasing the building’s
annual EUI. While each energy conservation method resulted in a decrease in the
building’s EUI, the top three energy conservation methods were implementing highperformance windows, modifying the building’s insulation, and changing the materials
that make up the building. Modifications to the building’s orientation and form did not
contribute to a significant reduction in the building’s EUI. High-performance windows
decreased the buildings EUI by about 30 percent while reorientating the building to
maximize natural daylight decreased the EUI by about 5 percent. The remaining energy
also decreased the annual EUI of the building. The order of most to least effective
energy conservation method is listed in the table about (see Figure 4.29).

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Chapter Five: Energy Conservation Method Categories
Chapter 5 focuses on the review of the simulations results from the grouping of
the simulated energy conservation methods that were ran in the previous chapter, their
outcomes, and how efficient these groups are in achieving Zero Net Energy
performance target for a home in Lagos, Nigeria.
5.0 Overview of Chapter 4 Results
In the prior chapter, various energy conservation strategies were tested in their
effectiveness in achieving net-zero energy (ZNE) performance. These simulations were
designed to explore how different aspects of the case study’s design, orientation,
materials, and building systems impact its overall energy efficiency in Lagos’s climate.
The findings provided insight into maximizing the performance of design strategies
that can be incorporated into the existing building’s design for further energy
efficiency. As a reminder, a list of parameters were tested individually. These
parameters included the use of L-shaped windows, shading devices, overhangs and
balconies, window sizing, repositioning of building, modified insulation, the use of
high-performance windows, and changes in material selection. Of these parameters,
one of the key findings was the significant impact of the building’s orientation on its
energy performance. Orienting the building to maximize natural daylighting and
minizing heat gain resulted in a reduction in cooling loads. In addition to this, the
placement and sizing of the building’s windows, more specifically east-facing
windows, showed to play an important role in controlling solar gain, and the use of

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operable windows allowed for more natural ventilation, reducing the reliance on
mechanical energy which is even more effective in milder climates like Lagos and
countries like Nigeria where energy systems are not always common. Increased
insulated levels led to a reduction in heat loss, while the use of shading devices,
overhangs, and/or balconies continued to lessen the amount of overheating that the
building experienced during peak sunlight hours. Using sustainable materials with high
thermal mass helped to stabilize the building’s indoor air temperatures. Of the explored
energy conservation methods, the modification of insulation and the incorporation of
high-performance windows were the most effective as they resulted in new EUIs of
113.64 kWh/m²/year and 112.17 kWh/m²/year respectively.
Despite the positive results of from the simulations, several performance issues,
related to the building’s design and envelope, in energy efficiency were identified. This
showed that there was room for improvement and remaining areas that needed to be
addressed. Significant issues included the use faulty material choices as there were still
instances that allowed for excessive heat transfer. This resulted increasing both the
cooling and heating loads when needed, however there was still a huge margin that
needed to be addressed as opposed to simply selecting materials with higher R-values
that may not even be accessible in the community. The window-to-wall ratio on the
east side of the building allowed for excessive solar heat gain during peak sunlight
hours. This means that while altering window sizes on the east side of the building
improved the building’s overall EUI, the effectiveness of this method varied as it
depended on where light would enter the building throughout the day, therefore not

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every unit benefited from this modification. This result led to inconsistencies in energy
performance that could be addressed by reducing window-to-wall ratio in these areas
and combining this method wih the use of shading devices and accommodating for all
units within the complex. To address these hiccups, the simulated energy conservation
methods can be grouped together to produce a lower EUI and significantly improve the
building’s overall performance.
5.1 Grouping
This section discusses the purpose for grouping the simulations together, the
methodology for studying groups using Cove.Tool, and the steps that go with it.
Purpose of Group Simulations
For this case study, a “group” was defined as a collection of individual design
parameters, or simulations, that share a common effect on the building’s overall energy
performance. Each group is put together based on the role that each energy
conservation methos (ECM) plays in terms of energy savings, such as passive solar
gain, insulation performances, and ventilation. Grouping these simulations, or ECMS,
makes it easier to analyze the contribution of each parameter and develop better
solutions as a result of how they interact with one another. Each group also allows for
a more effective approach in attempting to lower the building’s EUI in a way that
requires less modification of another group. This means that groups do not depend on
each other to see changes in energy efficiency.

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The simulated energy conservation methods were grouped into three categories
– (1) building design, orientation, and form, (2) envelope and materials, and (3)
fenestration, placement of windows, and operable windows — to analyze their
contribution in achieving net-zero performance in a systematic way. Group 1: Building
Design, Orientation, and Form focuses on the broader architectural decisions that
determine how the building interacts with the environment surrounding it. Group 2:
Envelope and Materials places an emphasis on the building’s external shell and how it
regulates temperature flows. Group 3: Fenestration, Placement of Windows, and
Operable Windows examines the impact of windows and other openings on energy
performance. This grouping approach allows for a deeper understanding of how
different aspects of the building’s design interact and targets specific areas of challenge
that were identified in Chapter 4.
Overall, the decision to created energy conservation groups was driven by the
need for a more organized approach that aligns specifically with the challenges faced
by the Lagos apartment building’s case study mentioned earlier. By addressing the
simulations’ impacts on energy performance individually, placing them into groups
shows the further steps that can be taken to modify the existing case study.

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5.2 Methodology for Studying Groups Using Cove.Tool
The rationale for grouping simulations by building design, envelope, and
fenestration stems from the distinct ways each of these elements influences energy
consumption. By isolating these components into specific groups, the analysis can
identify which factors have the most significant impact on reducing energy use and
improving overall building performance. To analyze the three groups—(1) building
design, orientation, and form, (2) envelope and materials, and (3) fenestration,
placement of windows, and operable windows—Cove.Tool’s energy modeling
software was used to simulate the groups and analyze each of their contributions. The
methodology used for studying these groups is structured around a multi-phase
simulation process involving baseline establishment, variable manipulation, and
performance optimization. The process is broken down as such: establishing the
baseline models, parametric simulation and variable manipulation, and performance
analysis.
Step 1: Establishing Baseline Models
Establishing the baseline model was relatively simple as the existing model of
the case study was simulated earlier. This simulated model was used to explore
individual parameters as well as grouped energy conservation methods. For all three
groups the baseline model was not altered and inputs remained stagnant at what they
were set to originally. The simulated baseline model initially used standard wall
assemblies with typical insulation levels and local building materials, however these
materials were altered in Chapter 4 of the study. As a result, the baseline model for

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Group 2 (Envelope and Materials) also remained unchanged but would take into
account the new values of insulation levels. The baseline model of the simulated
existing building included standard-sized windows and no additional shading devices
or operability controls, therefore these characteristics were also left unchanged.
Step 2: Parametric Simulation and Variable Manipulation
Once the baseline models were established, parametric simulations were
conducted in Cove.Tool to assess how changing key variables within each group
affected the overall energy performance of the building. This allowed for a quicker
modification of multiple parameters at the same time. The software’s solar exposure
and daylighting analysis features were crucial in these phases. The solar exposure
simulation helped determine the intensity of solar radiation on different building
surfaces, providing insights into how orientation and form could reduce heat gain.
Variables such as insulation levels, custom wall assemblies, and thermal mass were
altered in the simulations. Cove.Tool's thermal comfort analysis helped in evaluating
how changes to the building envelope could affect indoor temperature. This allowed
for a comparison of various insulation and material configurations at once to show if
the combination provided the best results in thermal performance and energy
efficiency. Different window sizes, placements, and shading strategies were modeled
to evaluate their impact on natural lighting and solar heat gain. As a result of this
grouping, window-to-wall ratios were adjusted, and operable windows were tested to
enhance natural ventilation. The addition of shading devices such as overhangs,
louvers, and external blinds was also simulated. Cove.Tool’s solar gain analysis
allowed for evaluation of how fenestration strategies affected the building’s cooling

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loads. By calculating direct sunlight exposure through windows at various times of the
day and year, the simulations provided insights into how different configurations could
reduce cooling energy use while maintaining adequate daylighting improving the
building’s overall annual EUI.
Step 3: Performance Analysis and Comparison
After the parametric simulations were completed, Cove.Tool's energy analysis
features were used to evaluate the performance of each group similar to how each
parameter was analyzed in chapter 4. EUI, thermal comfort, and carbon emission were
all determined in their respective groups. Once the best-performing configurations
from each group were identified, these configurations were re-tested and combined in
new simulations to explore their collective impact on the building’s energy
performance. By integrating the high-performance features of all three groups, the goal
was to optimize the building’s design holistically, achieving the lowest possible EUI
and carbon footprint, making the building’s energy usage that much closer to zero.
Comparative analysis tools in Cove.Tool’s report were used to show the differences
between the grouped configurations. This provided a clear depiction of which
combinations of building design, envelope, and fenestration strategies offered the
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5.3 Parameters Considered for Grouping
Building Design and Orientation
One of the primary criteria for grouping simulations is the building's overall
design and orientation. This group analyzes how the shape and placement of the
building on its site affect daylighting, heat gain, and passive ventilation. Orientation
refers to the positioning of the building relative to primary directions (North, South,
East, and West), particularly in terms of its major facades and window placement. In
tropical regions, aligning the building to reduce exposure to direct sunlight, particularly
on the east and west facades, can significantly cut down on cooling requirements. The
earlier simulations (Chapter 4) test various orientations, including north-south and eastwest plans, to determine which configuration optimizes natural lighting without taking
awat thermal comfort. When considering building design as an isolated parameter in
Chapter 4, simulations determined the impact of different forms, such as compact,
elongated, or L-shaped configurations. These shapes influence how much heat is
absorbed by the building's surfaces and how effectively natural light with affect the
existing model. The design also impacted airflow around and within the building. For
example, as seen earlier, a more compact building reduced the surface area of the
building.
Envelope and Material Selection
The building envelope—comprising the walls, roof, floors, insulation, and
materials used—forms the second major grouping method. The envelope acts as the
barrier between the indoor and outdoor environments. The simulations within this

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group evaluate the performance of combined materials and insulation types to assess
their thermal resistance (R-value) and capacity to store heat (thermal mass) and further
highlight how they perform as a whole.
Fenestration Strategies (Window Sizing and Placement)
The third key grouping method involves fenestration strategies, including the
sizing, placement, and operability of windows. Windows are vital for daylighting and
natural ventilation. Window placement and sizing was merged together to carefully
optimize and balance daylighting with thermal performance. The simulations in this
group analyze the effects of window-to-wall ratio (WWR), as well as the orientation
and size of windows. Larger windows on the north and south facades can provide a
good amount of daylight without excessive heat gain, while east- and west-facing
windows may need to be smaller amounts with shading devices to reduce direct solar
radiation. Additionally, the use of operable windows is assessed, in Chapter 4, and
grouped with the remaining ECMs to determine their ability to provide natural
ventilation. Shading devices, such as overhangs, louvers, or balconies, are also
considered as part of this group’s strategy. Dynamic shading devices or highperformance glazing, such as low-emissivity (low-e) glass, are explored in the
simulations to determine their effectiveness in reducing heat gain while allowing
natural light to penetrate the building.
The selection of high-performance configurations from the simulations is based
on their ability to optimize energy performance without compromising occupant
comfort. Grouping the simulations allows for a focused analysis of which combinations

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of design features, materials, and fenestration strategies provide the greatest energy
savings and contribute to the overall 2030 benchmark.
Figure 5.1 Grouped Energy Conservation Methods
5.4 Group 1: Building Design, Orientation, and Form
Building design, orientation, and form as a unit is a fundamental approach
in architecture that significantly influence a structure's performance, aesthetic
appeal, and environmental impact. The combining of these factors can lead to a
more sustainable built environment for occupants and thermal performance. For
instance, compact building forms with minimal surface area are seen to reduce heat
exposure while maximizing interior space, making them ideal for denser urban
areas. By analyzing these three elements as a whole, strategies that optimize natural
ventilation, maximize daylighting, and minimize heat gain, can be identified. Each
parameter plays a role in the group as they can all impact one another and
simultaneously. The orientation of a building can complement its form and design.
By intertwining these components, significant contributions can be made when it
comes to creating a more resilient building than the existing case study that

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responds well to the unique challenges of Lagos's urban environment. This ensures
a healthier and more comfortable living space for its occupants.
5.4.1 Impact of Design on Energy Efficiency and Thermal Performance
The orientation of the building played a crucial role in determining its exposure
to solar radiation and its ability to harness natural daylight. The simulations tested
multiple orientations, such as north-south and east-west, to determine how solar
exposure affects energy consumption. In the first part of the simulation process, the
existing building was rotated 90 degrees as that angle provided the most reduction in
terms of EUI. To remain cohesive, this grouping required that the new case studied
remained at 90 degrees as well (See Figure 5.3).
Figure 5.2. Case Study Rotated 90 degrees from Existing

The east-west orientation was explored to see how much more heat would be
absorbed by the building’s east and west facades in the previous portion of the study.

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It was found that reposition the building in this manner decreased the existing
building’s initial EUI of 156 kWh/m²/year by about 5% to 10%. The simulation
assessed whether there was a possibility to experience more improvement. In addition
to orientation, the form of the building significantly affects energy consumption
because different forms influence how temperatures are distributed and absorbed across
the building’s surfaces, as well as how airflow moves around and through the building.
The thermal performance of the building was heavily influenced by its form
and orientation. Thermal performance refers to how well the building maintains
comfortable indoor temperatures with minimal reliance on active heating and cooling
systems. The earlier simulations explored how different building forms distribute solar
heat throughout the day and how this affects the building’s overall energy performance.
It was found that compact building forms demonstrated better thermal performance due
to the reduced surface area exposed to the sun. Thought this was a beneficial finding,
the grouped simulation took into account this finding and the overall shape of the
building remained the same. Overhangs and shading devices were installed on all sides
of the building to accompany the repositioning of the building (Figure 5.4).
Figure 5.3. Overhang modeled with shading devices

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Figure 5.4. Combined Shading Device Locations
The results from simulating Group 1 resulted in a new overall EUI of 100.98
kWh/m²/year (Figure 5.1). This is about a 35% reduction from the existing building’s
EUI of 156 kWh/m²/year. In addition to this, the simulated model would receive 9
LEED points and result in a 39% carbon reduction.
Figure 5.5. Group 1 EUI Baseline Energy

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Figure 5.6. Group 1 EUI Baseline Breakdown for Proposed Model
5.5 Group 2: Building Envelope and Materials
The building envelope is a critical component in architectural design, serving
as the interface between the interior and exterior environments. It encompasses all
elements that separate conditioned spaces from unconditioned ones, including walls,
roofs, windows, doors, and foundations. This structural skin plays a crucial role in
protecting the building from external elements.
Materials used in the construction of the building envelope significantly
influence its performance and sustainability. However, when the correct materials are
paired with all aspects of the building envelope a significant amount of improvement
in a building’s performance can easily be seen. Selecting appropriate materials can

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relate directly to performance impact. Integrating the study of building envelope and
material strategies into a cohesive framework offers significant benefits by examining
these components collectively. This grouping method allows for a comprehensive
evaluation of how optimized building envelopes can work in tandem with sustainable
materials and innovative energy conservation techniques to create resilient, energyefficient structures. This grouping also promotes the building’s long-term sustainability
and adaptability in the face of climate change.
5.5.1 Performance Results
This section discusses the performance results of grouping building envelope and
materials selection ECMs together to form one group. It also discusses the specific insultation
strategies and high-performance materials that led to the performance results.
Insulation Strategies
In the Group 2 simulations, custom insulation systems were incorporated into
the existing design to determine their impact on reducing energy loads. HighPerformance Insulation was determined to be the most beneficial type of insulation in
the first part of the energy conservation method analysys. Materials such as rigid foam
and spray foam insulation were introduced to assess their ability to reduce thermal
transfer. High-performance insulation extruded polystyrene (XPS) was determined to
be the most useful material in controlling heat gain through the walls and roofs. In the
previous section, Cove.Tool’s Assembly Builder plug-in was used to modify the
insulation values, allowing for real-time comparisons between different material

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configurations. In the baseline model, the insulation levels were set according to
standard regional building codes. These values were then increased in successive
simulations to test the impact of more advanced materials.
High-Performance Materials
The choice of materials in the building envelope also significantly impacted
energy efficiency. The Cove.Tool plug-in for material selection was used to modify
wall assemblies and roofing systems, offering different combinations of materials and
thicknesses. This plug-in provided real-time energy performance metrics based on the
selected material configurations, allowing for rapid testing and optimization. Specific
material strategies included in the Cove.Tool assembly were custom extruded
polystyrene with a thickness of 105 mm, EPDM roofing membrane, and Plywood with
a thickness of 19 mm. With the modification of these two categories individually, new
values were found (See Chapter 4).
Grouping together these two parameters resulted in a greater amount of
reduction also. The results from simulating Group 2 resulted in a new overall EUI of
98.24 kWh/m²/year (Figure 5.7). This is about a 37% reduction from the existing
building’s EUI of 156 kWh/m²/year. In addition to this, the simulated model would
receive 7 LEED points and result in a 40% carbon reduction.

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Figure 5.7. Group 2 EUI Baseline Energy

Figure 5.8. Group 2 EUI Baseline Breakdown for Proposed Model
5.6 Group 3: Fenestration, Window Placement, and Operable Windows
Fenestration is the design and arrangement of windows, doors, and other
openings in a building’s exterior. In building design, particularly in energy-efficient
architecture, fenestration plays a critical role in influencing the flow of natural light,

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air, and energy within a space. Window placement, sizing, orientation, and operability
are essential components that directly affect how well a building performs in terms of
both thermal comfort and energy use. Because of this, the strategic placement and use
of windows is an essential factor in Zero Net Energy (ZNE) building design.
Alongside the other components mentioned within the study, window
placement and orientation are key factors that can influence a building's energy
efficiency. Operable windows offer another essential strategy, allowing for natural
ventilation by enabling airflow through the building. Cross-ventilation and stacked
ventilation systems, which rely on properly placed operable windows, are proven
methods to improve airflow and reduce indoor temperatures.
Grouping the fenestration strategies of window placement, sizing, and operable
windows together in this section offers a better understanding of the role that glazing
and fenestration plays in terms of improving a building’s performance. By evaluating
these factors as an entire system rather than isolated ones, it is possible to gain deeper
insights into how they impact the building’s EUI and if it is significant or not.
The Group 3 simulations explored three key factors: daylighting, shading, and
ventilation. When it comes to daylighting, the placement and size of windows are
critical for ensuring that natural daylight is sufficient to meet the lighting needs of a
building during the day. Proper daylighting reduces the reliance on artificial lighting,
thereby lowering the building’s energy consumption. The study in the previous chapter
found that the simulations revealed that buildings with larger windows on the north and
south-facing facades achieved higher daylighting levels while minimizing heat gain. In

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contrast, east and west-facing windows required more shading strategies, such as
overhangs, to reduce heat gain without sacrificing daylight.
The earlier study also found that operable windows were good at reducing
cooling loads by allowing for natural ventilation. The ability to ventilate the building
using outdoor air was useful during the early morning and evening, when outdoor
temperatures were lower than indoor temperatures. Cross-ventilation and stack
ventilation strategies were both tested. Operable windows reduced the need for
mechanical cooling (See Chapter 4). Because of this the idea of a curtain wall was
implemented into this portion of the study (Figure 5.10).
Figure 5.9 Curtain Wall and Fenestration Placements
Findings
Performance results were revealed after using Cove.Tool’s plug-in and inputs
for fenestration optimization, window placement, size, and operability. These inputs
were adjusted in real-time to observe how changes impacted overall building
performance as a unit.Operable windows were strategically placed to encourage cross-

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ventilation, making sure that fresh air could flow through the building and cool interior
spaces adequately (Chapter 4). The placement of the windows did not need to be altered
in this section of the grouped simulations as they remained stagnant for this portion of
the study as well. Based on the findings in the prior section of the simulations, crossventilation was the most feasible solution in terms of ventilation methods. While
stacked ventilation would also be beneficial, it would require extreme reconstruction
of the building’s existing design that would go further than retrofitting. As a result,
operable windows were placed on opposite sides of the building.
Figure 5.10 Group 3 Fenestration and Window Operability Inputs

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Figure 5.11 Group 3 Custom Curtain Wall Fenestration Inputs
To accurately simulate the grouping, new glazing and fenestration was
implemented. These new elements were operable windows, vertical fenestration, and
operable skylight inclusion. Grouping together these energy conservation methods
reduced the baseline model’s EUI, however, it was not he most effective approach out
of the three. The results from simulating Group 3 resulted in a new overall EUI of
103.80 kWh/m²/year (Figure 5.13). In addition to this, the grouping resulted in 8 LEED
points and about a 37% reduction of carbon emmissions.

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Figure 5.12 Group 3 EUI Baseline Energy

Figure 5.13. Group 3 EUI Baseline Breakdown for Proposed Model

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5.7 Grouped Simulations in Comparison to ZNE Targets
This section is about the buildings energy performance results after grouping and their
relation to local industry standards.
5.7.1 Comparison to Local Industry Standards
Local industry standards for ZNE in Lagos, Nigeria, take into account several
factors, including regional climate conditions, energy consumption patterns, and the
potential for renewable energy generation. These benchmarks are often derived from a
combination of government regulations, guidelines from organizations such as the
Nigerian Building Energy Efficiency Code (NBEEC).
In Lagos, the NBEEC serves as a framework for assessing energy performance
and guiding the design of energy-efficient buildings. This system establishes specific
energy use intensity (EUI) targets tailored to the local climate (Nigerian Green Building
Council, 2021). According to the Lagos State Government's Sustainable Building
Code, achieving a minimum EUI of 150 kWh/m²/year is predictable for new
constructions, representing a need for the implementation of energy efficiency in the
region (Lagos State Government, 2019).

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5.7.2 Energy Savings Achieved Across Groups
The grouped simulations encompass several distinct design strategies, each
evaluated for its potential to reduce energy consumption. The energy consumption for
each group was simulated using Cove.Tool and the results are summarized in the table
below (Figure 5.16).

Figure 5.14 Proposed EUI Outcomes with Grouped ECMs
Comparison to 2030 ZNE Targets
The 2030 ZNE targets for buildings in Lagos are defined as achieving a
maximum EUI of 33 kWh/m² annually. This target aligns with global initiatives to
transition towards sustainable building practices, particularly in regions vulnerable to
climate change. Majority of the regions aiming to hit this target are situated in the
Western and Southern parts of Africa, with primary countries including Nigeria,
Ghana, the Ivory Coast, and Benin.
By comparing the simulated EUI of each group against the 2030 ZNE target, we can
assess the overall effectiveness of the design strategies implemented. While neither of

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the groups annually EUI has reduced to 33 kWh/m²/year, it is safe to say that the study
takes significant strides in reaching that baseline.
5.8 Summary
Chapter 5 focused on reviewing the simulation results from the grouping of the
energy conservation methods that were ran in the previous chapter, their outcomes, and
how efficient these groups are in achieving Zero Net Energy performance target for a
home in Lagos, Nigeria. Each “group” is a collection of individual design parameters,
or simulations, that share similar effects on the building’s EUI. The three ECM groups
were building design/form, building envelope and materials, and fenestration and
window placement. Of the three grouping methods, group 2 (building envelope and
materials), encouraged the existing building’s annual EUI so experience the most
reduction. As a result the building’s EUI dropped to 98.24 kWh/m²/year (Figure 5.17).
Group 1 and group 3 also contributed to overall reduction, however not as much as
group 2. The implementation of their modifications caused the building’s annual EUI
to drop to 100.98 kWh/m²/year and 103.80 kWh/m²/year respectively (Figure 5.17).
While the overall results reduced to Lagos’s 2030 ZNE target of 33 kWh/m²/year, these
reductions show the importance of passive ZNE design in the city and emphasize a
gradual shift toward energy efficiency.

166
Figure 5.15 Proposed EUI Outcomes with Grouped ECMs in Comparison
Chapter Six: Conclusions and Future Works
6.1 Final Discussion
Lagos’ urban housing due to rapid population growth faces many challenges
that result in affordability issue and environmental concerns. Globally, other
developing cities also face similar problems. These problems prompt an urgent need
for sustainable solutions like net-zero housing. Incorporating passive design strategies
can reduce energy use, low carbon emissions, and improving living conditions for
residents. Because Lagos faces frequent, unreliable power supply, the solution to
incorporate passive design offers flexibility and effectiveness. By adopting net-zero
housing, the city addresses both housing shortages and climate challenges. A case
showed that modifying a typical multi-family home in Lagos could save 38% of energy,
bringing it that much closer to net-zero energy goals.
6.1.1 Present Concerns
Today, urban housing is still one of the most critical issues in rapidly growing
cities like Lagos, Nigeria. The constant increase of people to the city continually
increases housing shortage due to affordability concerns and environmental stress

167
(Opoko & Oluwatayo, 2014). Globally, many cities are stilled faced with similar
challenges, emphasizing the importance of innovative solutions that are tailored to both
housing demand and environmental sustainability. Net-zero energy remains a
promising solution in Lagos, where the growing populations lead to informal
settlements and substandard living conditions, negatively effecting overall occupant
comfort. Integrating renewable energy sources, alongside mechanical and passive
design strategies, can cause net-zero housing to significantly lower annual energy
usage. Because renewable energy sources are not as effective in cities like Lagos,
Nigeria, passive design strategies can be seen as a more beneficial solution. By taking
this approach Lagos' pressing energy challenges that affect occupant comfort in
housing, like power fluctuations and an unreliable grid, are directly addressed.
Given Lagos’ tropical climate and location off of the coast of Nigeria, the city
is especially exposed to rapid climate change, experiencing extreme weather and
energy shortages. Net-zero housing can mitigate these risks with the use of sustainable
construction practices that reduce greenhouse gas emissions. The hypothesis that
stressed that modifying a typical multi-family home in Lagos with passive design
strategies and simulating its energy performance could save at least 40% of energy
annually while enhancing living comfort for its residents was not entirely supported.
Presently, Nigeria's rate of urban expansion has been on the rise, increasing
population in urban areas at an exponential rate. Population sprawls have led to several
issues when it comes to housing, specifically relating to energy efficiency. In Africa,

168
the meaning of sustainability is different as the continent often struggles with more
complex environmental challenges and the exploitation of its natural resources and
materials. Of these environmental challenges, the country’s energy supply crisis
remains dominant due to its lack of adequate infrastructure, limited investment in the
power sector, and government challenges that limit the management of the power
system (Opoko & Oluwatayo, 2014). These pose a huge issue in cities with dense
populations and unreliable power supply like Lagos. Net-zero energy design, by use of
passive design strategies, results in a building that produces the same amount of energy
that it consumes (HMC Architects, 2020). An existing urban housing project, or typical
multi-family home in Lagos, can be modified and reconfigured to achieve net-zero
energy consumption, and increased comfort, and contribute to a more sustainable and
promising Nigeria.
6.1.2 Adaption to Local Climate and Culture
The workflow served as an investigation on how net zero design can be further
adapted to the local climate conditions of Lagos and its future climate characteristics.
The workflow of the study included a site and climate analysis, a parameter hunt, an
analysis of the existing case study, analysis of energy conservation methods, and
modification to an existing case study through grouped energy conservation methods.
After each simulation was completed, a comparison of the existing and new model’s
energy characteristics was made and summarized. After the site and climate analysis,
the geometry and EPW weather data files were analyzed using the Honeybee

169
component. Zone measures were then uncovered to decipher how thermal comfort can
be improved. The entire process incorporated the use of real-time variables and inputted
components that would later be updated throughout the study. The use of Grasshopper
scripting provided weather patterns that aided in the visualized climate data.
The parameter hunt was carried out with the use of Cove.tool, Climate
Consultant, and an interview process, and provided a list of strategies that could be
used Lagos. Interviews were conducted with residents that currently reside in Nigeria.
These interviews provided valuable information regarding the current characteristics
of traditional Nigerian homes and how their design impacts the lives of those whole
occupy the space. The parameter hunt also included a literature review of existing case
studies and design precedents was conducted. The parameters were then organized into
lists to determine which would be most effective to the area and the purpose of the
project: increasing energy efficiency and improving thermal comfort.
Figure 6.1 Methodology Diagram

170
6.1.3 Single ECMs
The existing features of the case study was chosen because its initial features
are made up of the usual construction materials and habits that are typically used in
Lagos. The base model had three stories and is 5,779 square feet (537 m²). Its primary
material composition consists of concrete blocks, laterite, and cement. Each of the six
units is about 89.45 m². It initially consisted of a flat roof with no insulation and singleglazed windows. Each unit has two bedrooms, three bathrooms, a living space, a
kitchen, an entry way, and a covered porch.

Figure 6.2 Apartment Unit Program Dimensions
The pre-simulation findings highlighted key energy performance issues in
Nigerian multifamily housing developments. Poor insulation and inefficient windows
cause significant heat buildup that increases cooling demands. Despite natural

171
ventilation, the buildings EUI remains above ZNE targets. The roof of the building has
a moderate U-Value of 0.255 W/m²K but could be improved. The walls, spandrels, and
windows have higher U-Values that lead to poor insulation. The windows have a Solar
Heat Gain Coefficient (SHGC) 0.21 that limits heat entry, but the lack of blinds or
shading devices directly impact energy efficiency.
The model has different usage patterns and schedules that can be modified to
simulate real-life scenarios and comparing energy consumption. It does not have
daylight or occupancy sensors, therefore the building operates on a basic setup where
lighting and climate is changed manually. Without the use of sensors, energy
management stands still and depends on its initial fixed settings.
Since Lagos experiences tropical climates with distinct seasons for wet and dry
periods, as opposed to winters and summers, the monthly energy usage of the existing
makes sense because it evidently changes in response to the climate that he residence
experiences during that specific time. In Lagos, energy usage showed higher
consumption rates during the hotter months and lower consumption rates during cooler
months. The annual energy consumption of the existing apartment building in Lagos
was calculated using the monthly distributed values (Figure 6.3). The monthly energy
usages added up to be 83,956.26 kWh annually. To calculate the energy consumption
the following equation was used:
𝐴𝑛𝑛𝑢𝑎𝑙 𝐸𝑛𝑒𝑟𝑔𝑦 𝑈𝑠𝑒 = 156.18 𝑘𝑊ℎ/𝑚²/𝑦𝑒𝑎𝑟 𝑥 537 𝑚2 = 83,956.26 𝑘𝑊ℎ

172

Figure 6.3. Monthly Energy Usage of Actual Existing Structure
The energy conservation methods were analyzed individually include highperformance windows, modified insulation, overhangs, material selection, shading
devices, L-shaped windows, east-window sizing, and epositioning the building to
minimize heat gain and maximize natural daylight.
Figure 6.4. Energy Conservation Methods and Their Final Outcomes

173
6.1.4 Grouped ECMs
The energy conservation methods were then placed into three groups: building
design/orientation, building envelop and materials, and fenestration/window
placement. Rotating the building while adding both overhands and shading devices
caused a 35% reduction from the existing building’s EUI 156 kWh/m²/year. This group
(group 1) combined three single energy conservation methods: repositioning of the
building, overhangs, and shading devices. The result of combining these three
strategies resulted in an overall EUI of 100.98 kWh/m²/year (Figure 6.5)
The choice of materials of the building envelope effected energy efficiency. For
Cove.Tool plug-in’s Assembly Builder was used to edit wall assemblies and roof
systems. The strategy included the implementation of custom extruded polystyrene
with a thickness of 105 mm, EPDM roofing membrane, and Plywood with a thickness
of 19 mm. Grouping together materials selection and modified insulation resulted in a
new EUI of 98.24 kWh/m²/year (Figure 6.5). This is a 37% reduction form the existing
building’s intial EUI.
Because fenestration influence thermal and lighting performance of the
building, group 3’s simulations directly impacted just that. The group explored three
main factors including daylighting, shading, and ventilation. When it comes to
daylighting, window placement and size are critical to make sure that the building
experiences a sufficient amount of natural light throughout the daytime, lowering

174
energy usage. The result found that buildings with larger windows on the north and
south-facing facades achieved better daylighting while minimizing overall heat gain.
Group 3 resulted in a new EUI of 103.80 kWh/m²/year (Figure 6.5).
Figure 6.5. Grouped Energy Conservation Methods and Their Final Outcomes
6.2 Future Work
This section discusses future ways to further analyze the net-zero urban housing
design in Lagos, Nigeria, the importance of doing so, and how they can be carried out.
6.2.1 Future Work Topics
Impact of Study Modifications on Single-Family Homes
Single-family homes can also benefit from the study’s emphasis on energy
efficiency and net-zero urban design for urban multifamily housing in Lagos. Although
single-family homes usually have different architectural layouts and energy

175
consumption characteristics, applying the same modifications that were proposed in
this study can evaluate how single-family homes’ energy consumption can be
improved. Improved building orientation, building envelop modifications, and
improved fenestration may all contribute to positive changes in an existing building’s
trends. Understanding the key differences and changes that occur in each energy
conservation method could aid in dwindling down solutions that could work for a wider
variety of housing types in Lagos. This would eventually lead to solutions that promote
energy efficiency and improve occupant comfort for both urban and rural residences.
Comparing Single-Family Homes and Urban Housing Developments
A comparison of how single-family homes perform in Lagos, Nigeria as
opposed to urban housing developments could also be incorporated into a further
investigation of this study. Cove.Tool and Rhinerceros 3D can be used to analyze the
home’s existing characteristics and compare its outcomes to the benchmarks of existing
urban housing developments in the same area. Usage in a single-family home can differ
significantly in comparison to urban housing developments due to its scale, occupancy
habits, and density. This future study could be carried out by observing how each
housing typology responds to the implementation of passive design strategies and its
impacts to decipher which are the most energy-saving. By doing this, researchers can
develop personalized solutions for each housing type. This comparative study would
also let designers know which methods are the best for achieving net-zero energy in
various residential settings.

176
Advanced Technologies for Renewable Energy Integration
Exploring more advanced technologies for renewable energy like solar thermal
systems photovoltaics (PVs), thermal systems, and wind energy is also essential to
achieving ZNE in Lagos’ buildings. Though renewable energy is not always effective
in many parts of Africa (Pueyo, 2018), it is important to further analyze to what extent
it can be applied in the further. These techniques area great option because wind energy
may be less beneficial in climates like Lagos. To further advance this research an
evaluation on the performance and financial trends of integrating renewables into both
residential and commercial developments can also be beneficial to ensure that these
methods can be customized to scale and cost-effective to Lagos’ urban housing.
Urban Housing and Policy Planning
In many countries that have successfully incorporated ZNE building practices,
government policy planning plays a huge role (Jha, Miner, & Stanton-Geddes, 2013).
Best practices and good habits start from the top and then work their way down to the
communities (Jha, Miner, & Stanton-Geddes, 2013). The establishment of zoning laws,
building codes, and incentives for energy-efficient construction practices can positively
influence how buildings are designed. These future studies could evaluate the present
policy characteristics in Lagos and research how changes to national building codes
and cities’ policies can lead to the adoption of ZNE building practices. The involvement

177
of government organizations, including Lagos’s Ministry of Housing, is important
when it comes to the inclusion and implemenentation of these principles on a greater
scale nationally.
Water Conservation in Sustainable Design
The conservation of water is also an essential part of sustainable development
and building development in Lagos. Future studies could analuyze how water
conservation methods including rainwater harvesting, flow fixtures, and water
recycling can be integrated into net zero building urban housing design. By integrating
both energy and water conservation techniques a buildings can be efficient and resilient
to the environmental challenges that may occur while it ages.
Guideline for Energy-Efficient Buildings (Developing an Energy Efficiency
Code)
To further expand this study, a guideline for energy efficiency in building
practices can also be developed and given to Nigeria’s Housing Ministry. This future
building code would establish that new construction and renovation building projects
meeting the requirements that accompany energy saving, thermal comfort, and
sustainability. A future research project could establish a code that takes into account
Lagos’s unique climate and socioeconomic characteristics. By focusing on this, energy-

178
efficient building practices could become a required step in implementing meaningful
and sustainable strategies for the future.
6.3 Summary
Net-zero energy (NZE) passive strategies can be used for housing solutions for
urban housing in Lagos, Nigeria. While it seems as though Nigeria is doing better than
many countries in terms of electricity usage, this mainly due to the lack of energy
resources in the country. Also, while saving energy is a great thing, thermal comfort
plays a significant role in effectively improving urban housing and leading to energy
efficiency. The main going of this research was to explore which passive design
methods contribute the most to energy conservation. In doing so, a model of a typical
multi-family housing unit in Lagos and its energy performance was analyzed and
energy conservation strategies were added in attempt to improve the building’s overall
EUI. These passive conservation strategies included high-perfomance windows,
modified insulation, overhangs, material changes, shading devices, L-shaped windows,
East facade window sizing, and the repositioning of buildings.
This impacts Lagos’ growing urbanization, and it also contributes to the global
push for sustainability and energy efficiency in housing. By implementing these
modifications in future projects, Lagos’ dense population and lack of proper energy
supply would not be as big as an issue as it is now and thermal comfort would be
improved. By focusing on net-zero energy solutions, this study shows a pathway to

179
reducing reliance on the current faulty electricity grid. These modifications all reduced
the building’s annual EUI.
Modified insulation, the installation of overhangs, and the implementation of
high-performance windows were the most effective methods of conservation. These
improvements lowered the building’s overall EUI to 113.64 kWh/m²/year, 122.75
kWh/m²/year, and 112.17 kWh/m²/year respectively. Of the grouped energy
conservation methods, Group 2 (Materials Selection) contributed to the most reduction
in the building’s EUI, dropping from 156 kWh/m² to 98.24 kWh/m² annually.

180
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APPENDIX A
1. Interview Questions for Nigerian Residents
Figure 2.7. Interview Questions for Nigerian Residents
2. LEED Evaluation Information
A preliminary LEED evaluation of standard apartment buildings in Nigeria
shows that most do not meet basic sustainability criteria. The building being studied
has an initial LEED score of zero credits. The use of non-energy-efficient materials
and design methods, along with limited access to renewable energy, results in low
scores for energy and atmosphere credits (Atanda and Olukoya, 2019). The
assessment highlights key areas needing improvement, such as water management,

189
indoor air quality, and energy efficiency, which are often lacking in many Nigerian
homes. Additionally, the incompatibility of renewable energy options, like solar
panels, is a major hurdle for achieving better LEED ratings. These early insights
highlight the need for Nigeria's residential buildings to adopt more energy-efficient
systems and construction techniques.
LEED Points and Certification
The insulation had a positive impact on the LEED certification, earning 13
points out of a possible 18 for the EAc2 Credit. This underscores the significance
of passive design strategies like insulation in reducing energy consumption and
improving a building’s sustainability profile. The use of materials such as XPS and
EIFS also helps to meet both local and international green building standards that
Lagos aims to follow and consider.

Abstract (if available)

Abstract Urban housing presents a significant challenge in fast-growing cities like Lagos, Nigeria. The inflow of people to the city often worsens housing issues, leading to problems with affordability and environmental stress. This situation is common in many cities worldwide, showing the urgent need for new solutions that address local housing requirements and prioritize environmental sustainability. As a result of this pressing issue, informal settlements and substandard living conditions have become the norm. Net-zero housing has emerged to be a promising solution that aligns with the world's shift towards sustainable development. In Lagos, net-zero housing has the potential to bring influential transformation. By incorporating renewable energy sources such as solar power, passive strategies, and energy-saving technologies, net-zero housing can reduce overall energy usage and carbon emissions and provide affordable, eco-friendly living spaces that complement the city's dynamic atmosphere. Because renewables are often insufficient in towns like Lagos, passive design strategies can be seen as a more beneficial solution. This approach directly tackles the energy challenges faced by urban areas like Lagos, where power supply is often unreliable and fluctuates daily. Net-zero housing is being implemented globally to combat climate change. Because Lagos is situated on the coast of southwestern Nigeria, it experiences a significant risk due to climate change effects, such as severe weather conditions and electricity generation. The city also experiences a hot, tropical climate for most of the year. Net-zero housing helps mitigate these effects by promoting sustainable construction practices and lowering greenhouse gas emissions. By embracing net-zero housing strategies, Lagos can lead the way toward a sustainable urban future, serving as a model for other cities worldwide with similar issues. This not only addresses the immediate housing needs of the city's residents but also makes a significant contribution to environmental sustainability.

A case study determined that a typical multi-family home in Lagos, Nigeria, could be modified using passive design strategies. After simulating its outcomes, at least forty percent of energy will be saved, bringing the home closer to achieving net-zero energy and making it more comfortable for those who occupy it.

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Creator Okonkwo, Chioma B. (author)

Core Title Net-zero cultural urbanism: the implementation of traditional and cultural net-zero urban housing design in Lagos

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Degree Conferral Date 2024-12

Publication Date 12/02/2024

Defense Date 11/06/2024

Publisher Los Angeles, California (original), University of Southern California (original), University of Southern California. Libraries (digital)

Tag energy efficiency,indoor cooling,Lagos,OAI-PMH Harvest,passive design,thermal comfort,urban housing,Zero Net Energy (ZNE) design

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