Heat Waves and Residential Buildings: Building Homes That Survive Extreme Heat (Part 3.1)
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This article is the third in GBCE's Extreme Heat series. In Part 1, we explored why extreme heat is becoming a long-term climate reality and an emerging risk for the building sector. In Part 2, we examined how cities and developers can respond through climate-responsive urban planning and building design. This article focuses on residential buildings and why homes must be designed to remain safe, comfortable and resilient as temperatures continue to rise.
Series overview
Home Is Becoming the Front Line of Climate Adaptation
By 2040, electricity demand for space cooling across South East Asia could climb to 300 terawatt hours, roughly matching the current combined electricity consumption of Indonesia and Singapore. That trajectory reflects a simple reality. For most people, home is where they seek refuge from extreme weather, yet during a heat wave it can become one of the most dangerous places to be if it is not designed to stay cool. [IEA]
As climate change drives more frequent, longer and more intense heat waves, residential buildings are facing new challenges. Many homes around the world were designed using historical climate data, assuming that temperatures would remain relatively stable over their lifespan. That assumption no longer holds true. Buildings completed today will still be standing in 2050 and beyond, when many regions are expected to experience significantly hotter summers than they do today. [Scientific Data / PMC]
For developers, architects and engineers, the question is no longer whether homes should adapt to rising temperatures, but how quickly those changes can be incorporated into everyday design.
Homes Were Never Designed for Today's Climate
Unlike storms or floods, heat waves build gradually. Several consecutive days of high temperatures allow heat to accumulate within walls, roofs and concrete structures. If buildings cannot release that heat overnight, indoor temperatures continue to rise, even after outdoor conditions begin to cool. [ScienceDirect]
This problem is particularly severe in cities. Dense development, dark paving materials, limited vegetation and waste heat from vehicles and air-conditioning systems create the Urban Heat Island effect, where urban neighbourhoods remain significantly warmer than surrounding areas. Warm nights prevent buildings from cooling naturally, increasing thermal stress for occupants and driving greater reliance on mechanical cooling. [Resources for the Future]
Poor building orientation, unshaded windows, inadequate insulation and limited natural ventilation further increase overheating risk. In many existing residential buildings, these features were not considered because extreme heat was not viewed as a major design challenge when they were constructed.
Why Residential Overheating Matters
Residential overheating is often treated as a comfort issue, but it is increasingly recognised as a public health concern. [WHO Housing and Health Guidelines]
High indoor temperatures can affect sleep quality, concentration and overall wellbeing. Older adults, young children, pregnant women and people with chronic illnesses are particularly vulnerable because they are less able to regulate body temperature during prolonged heat exposure. During severe heat events, homes that cannot maintain safe indoor conditions may increase the risk of heat-related illness, especially for occupants who spend most of their time indoors. [World Economic Forum]
Overheating also has economic consequences. As temperatures rise, households rely more heavily on air conditioning, increasing electricity demand during peak periods. This places additional pressure on energy infrastructure while exposing residents to higher utility costs. For lower-income households, access to cooling can become an affordability challenge, highlighting the importance of reducing cooling demand through better building design rather than relying solely on mechanical systems. [IEA]
Designing Homes That Stay Cool
The most resilient residential buildings do not depend exclusively on air conditioning. Instead, they minimise heat gain through passive design before using efficient mechanical cooling to maintain comfortable indoor conditions.
Building orientation is one of the most effective strategies. Positioning buildings to reduce direct solar exposure while capturing prevailing winds can significantly improve indoor comfort. External shading devices, recessed windows, balconies and overhangs help prevent solar radiation from entering the building envelope before it reaches the glazing.
Natural ventilation should also be considered from the earliest stages of design. Cross ventilation, operable windows and carefully planned internal layouts allow warm air to escape while encouraging natural airflow throughout living spaces. [ScienceDirect]
The building envelope is equally important. High-performance insulation, reflective roofing materials and high-performance glazing reduce unwanted heat transfer and improve indoor thermal stability throughout the day.
Landscape design should not be overlooked. Trees, green spaces, shaded courtyards and green roofs reduce surrounding surface temperatures while improving outdoor comfort and biodiversity. In dense urban environments, these measures also help mitigate the Urban Heat Island effect at the neighbourhood scale. [PMC]
Finally, designers should assess overheating risk using dynamic thermal modelling based on future climate scenarios rather than historical weather files. Designing for tomorrow's climate rather than yesterday's ensures buildings remain resilient throughout their operational life. [ScienceDirect]
Retrofitting Existing Homes for a Hotter Climate
The vast majority of homes that will exist in 2050 have already been built. Improving the resilience of existing housing stock is therefore just as important as designing climate-responsive new developments.
External shading is often the most effective first step. Installing awnings, shutters, external blinds or reflective window films helps prevent solar heat gain before it enters the home, reducing indoor temperatures with relatively low investment.
Natural ventilation can also be enhanced through simple operational and building improvements. Opening windows during cooler hours, improving cross ventilation, sealing unwanted air leaks and using light-coloured curtains or blinds can all improve indoor comfort while reducing reliance on mechanical cooling.
The building envelope offers the greatest long-term performance gains. Upgrading roof and wall insulation, installing cool or reflective roofing materials, adding external shading devices and replacing inefficient glazing with high-performance windows significantly reduce heat transfer and improve indoor thermal stability.
Mechanical systems should be upgraded only after passive measures have been considered. Replacing older air-conditioning units with high-efficiency cooling systems further reduces energy consumption while maintaining comfortable indoor conditions.
Together, these retrofit strategies can help protect occupants, lower cooling demand and prepare existing homes for a hotter future.
Existing Building Case Study: Energiesprong, Netherlands
Rather than replacing ageing housing stock, the Energiesprong programme demonstrates how existing homes can be transformed to perform for future climates. Thousands of social housing units have been retrofitted using prefabricated insulated façades and roofs, high-performance windows, improved airtightness and energy-efficient building systems, significantly reducing energy demand while improving indoor comfort throughout the year.
Although originally developed to achieve net-zero operational energy, many of the same retrofit measures also reduce overheating by improving the building envelope and limiting unwanted heat gain. As heat waves become more frequent across Europe, Energiesprong illustrates how large-scale residential retrofits can simultaneously improve climate resilience, occupant comfort and long-term building performance.
Sources
Energiesprong
European Commission
IEA EBC Programme
New Build Case Study: Kampung Admiralty, Singapore
Singapore's Kampung Admiralty demonstrates how climate-responsive design can improve resilience in high-density residential developments.
Designed by WOHA Architects, the mixed-use development integrates housing, healthcare, community facilities and extensive greenery within a compact urban site. Shaded public spaces, naturally ventilated circulation areas, sky gardens and abundant vegetation help reduce heat build-up while creating comfortable outdoor environments throughout the year. [Henning Larsen]
Rather than relying solely on mechanical cooling, the project combines passive design principles with landscape integration to improve thermal comfort and reduce energy demand. As cities across South East Asia continue to densify, Kampung Admiralty illustrates how residential developments can simultaneously support climate resilience, occupant wellbeing and sustainable urban living. [Dezeen]
What Residential Developers Should Do Now
Designing for extreme heat is no longer a future consideration. It is becoming a core requirement for delivering safe, resilient and future-ready housing. Developers should prioritise five actions.
● Design using future climate projections rather than historical weather data.
● Apply passive cooling strategies before increasing mechanical cooling capacity.
● Reduce solar heat gain through orientation, shading and high-performance building envelopes.
● Incorporate greenery and landscape as essential cooling infrastructure.
● Evaluate overheating risk during the design stage using dynamic thermal modelling.
These strategies not only improve occupant comfort and health but also reduce operational energy use, strengthen long-term asset performance and enhance resilience as climate conditions continue to change.
Looking Ahead
Heat waves are becoming a recurring feature of every summer rather than exceptional events. Residential buildings must therefore do more than provide shelter. They must protect the health, comfort and wellbeing of the people who live in them while remaining energy efficient and resilient under future climate conditions.
The homes we design today will shape how communities experience a hotter world for decades to come.
Next in the series: Heat Waves and Hospitals: Designing Healthcare Facilities for Extreme Heat, where we examine why healthcare buildings require an even higher level of resilience to protect patients, staff and critical services during prolonged heat events.
SOURCES
1. IEA, Roadmap towards Sustainable and Energy-Efficient Space Cooling in ASEAN — https://www.iea.org/reports/roadmap-towards-sustainable-and-energy-efficient-space-cooling-in-the-association-of-southeast-asian-nations
2. Typical and extreme weather datasets for studying the resilience of buildings to climate change and heatwaves, Scientific Data / PMC — https://pmc.ncbi.nlm.nih.gov/articles/PMC11116384/
3. How can we combine urban cooling strategies to effectively cool cities over the entire diurnal cycle?, ScienceDirect — https://www.sciencedirect.com/science/article/abs/pii/S0360132323005516
4. Urban Heat Islands 101, Resources for the Future — https://www.rff.org/publications/explainers/urban-heat-islands-101/
5. Report of the systematic review on the effect of indoor heat on health, WHO Housing and Health Guidelines — https://www.ncbi.nlm.nih.gov/books/NBK535282/
6. Why are older adults more susceptible to heat-related illness, World Economic Forum — https://www.weforum.org/stories/2023/07/older-adults-more-susceptible-heat-illnesses/
7. Staying cool without overheating the energy system, IEA — https://www.iea.org/commentaries/staying-cool-without-overheating-the-energy-system
8. How do urban heat islands affect the thermo-energy performance of buildings?, ScienceDirect — https://www.sciencedirect.com/science/article/abs/pii/S0959652622032905
9. Urban green space cooling effect in cities, PMC — https://pmc.ncbi.nlm.nih.gov/articles/PMC6458494/
10. Creation and application of future typical weather files in the evaluation of indoor overheating in free-floating buildings, ScienceDirect — https://www.sciencedirect.com/science/article/abs/pii/S0360132322002980
11. Kampung Admiralty, Henning Larsen — https://henninglarsen.com/projects/kampung-admiralty
12. WOHA creates green community for senior citizens with Kampung Admiralty in Singapore, Dezeen — https://www.dezeen.com/2018/12/07/kampung-admiralty-woha-singapore-world-building-year/
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