Understanding Thermal Comfort in Tropical Climates
Global standards for heating and cooling comfort are typically developed based on cooler, northern hemisphere climates. However, these benchmarks may not be as relevant in warmer regions, particularly in low-cost housing across Africa. Research conducted by Mak Okay-Ikenegbu highlights the need for localized thermal comfort models that reflect the realities of people living in tropical environments.
Defining Comfortable Housing in the Tropics
Comfortable housing in tropical Africa is defined as a space where individuals can live, work, and rest without experiencing excessive heat or discomfort. This does not necessarily require air conditioning. Instead, it focuses on natural ventilation, reducing heat buildup, and adapting to local climate conditions. Passive design techniques such as cross-ventilation, shading, and the use of breathable materials like adobe, earth blocks, or bamboo play a crucial role in maintaining thermal comfort.
These materials help regulate indoor temperatures, making them ideal for hot and humid climates. The goal is to create homes that support well-being while minimizing reliance on energy-intensive cooling systems.
Insights from Research on Housing Needs
Mak’s research revealed that residents in low-income, tropical settings like informal settlements in Nigeria have adapted to higher indoor temperatures than what international standards suggest. He developed a local thermal comfort model based on real-life experiences of people living in naturally ventilated earth and makeshift homes. This model reflects how people in these environments actually experience and adapt to heat.
Unlike existing models such as ASHRAE 55 and EN 16798, which are primarily based on data from temperate climates and mechanically cooled buildings, this model is tailored to the specific context of sub-Saharan Africa. It has the potential to guide architects, urban planners, and housing authorities in designing buildings that align with local needs.
What Does Better Housing Look Like?
Affordable, climate-responsive housing solutions prioritize the use of local and thermally appropriate materials. In Mak’s study, earth-based construction materials like mud or adobe walls were found to be more comfortable than materials such as scrap metal, timber planks, and plastics. These materials offer natural insulation and reduce heat gain.
In contrast, makeshift structures often made from corrugated metal sheets and tarpaulin tend to trap more heat, exposing occupants to extreme indoor conditions. Incorporating insulation and ventilation beneath roofing can significantly improve comfort at a very low cost.
Combining passive design strategies—such as shaded outdoor spaces, high ceilings, wide eaves, and cross-ventilation—with locally available, climate-appropriate materials can lead to better thermal comfort in low-cost housing.
New Findings and Their Implications
Mak’s research highlights the limitations of applying international comfort standards like ASHRAE 55 and EN 16798 in tropical climates. These standards were developed by organizations in the United States and Europe and are based on studies from cooler climates and mechanically cooled buildings.
His findings show that many indoor temperatures considered “too hot” by international standards were actually acceptable to residents. Based on actual feedback from Nigerian low-income households, his model suggests a higher tolerance for heat, with comfort temperatures ranging from 24°C to 40°C.
This indicates that global models do not fully account for the ways people in tropical climates adapt to their environment. It is essential to consider these local adaptations when designing affordable housing in hot climates.
Policy and Intervention Strategies
Local adaptive comfort standards are currently lacking in sub-Saharan African contexts like Nigeria. Housing policies should recognize the value of these local models and avoid imposing global standards. Governments and stakeholders must encourage the use of passive design techniques, such as shading and ventilation, and promote the use of sustainable, locally available materials.
Investment in community-led housing upgrades, especially in informal settlements, is also critical. Small improvements, such as adding windows for cross-ventilation or improving insulation, can greatly enhance comfort without significant costs.
By focusing on context-specific solutions, policymakers can create more resilient, affordable, and climate-responsive housing that meets the needs of communities in tropical regions.