What effect do reflective roofing materials have on energy use?

• A. They reflect solar radiation, reducing cooling loads.
• B. They trap heat, increasing cooling needs.
• C. They have no effect on energy use.
• D. They increase humidity indoors.

Answer: (A)

Reflective roofing materials work by bouncing a large portion of solar radiation away from the building, which reduces heat gain through the roof. When the roof stays cooler, the interior stays cooler and the cooling system doesn’t have to work as hard, lowering energy use for air conditioning. This effect is most noticeable in hot, sunny climates where cooling loads are a major energy driver. In colder climates, very reflective roofs can sometimes modestly increase heating needs, but the typical impact discussed in energy-efficient design is the reduction in cooling energy. The other options don’t fit because trapping heat would raise cooling needs, having no effect ignores the real impact of reflectivity, and humidity changes aren’t a direct result of roof reflectivity.