What is the effect of light-colored surfaces on solar heat gain in tropical buildings?

• A. They increase heat absorption.
• B. They reflect more solar radiation, reducing heat gain.
• C. They have no impact.
• D. They only affect aesthetics.

Answer: (B)

Light-colored surfaces have high reflectivity, or high albedo, meaning they bounce a larger portion of incoming solar radiation away rather than absorbing it. In tropical buildings, where the sun’s intensity is strong, this reduces the amount of heat that gets stored in the exterior walls or roof and then conducted or radiated indoors. So interior spaces stay cooler and cooling loads are lower. Darker surfaces, by contrast, absorb more energy and contribute to higher heat gain. The cooling benefit of light colors is most pronounced on surfaces exposed to direct sun, especially roofs, though shading, insulation, and ventilation also play important roles in overall thermal performance.