Which factor most directly reduces radiant heat gain from the roof?

• A. Dark-colored roof
• B. Reflective roofing
• C. Large window spacing
• D. Increased insulation only

Answer: (B)

Radiant heat gain from the roof is driven by how much solar energy the roof surface absorbs. A reflective roof has high solar reflectance, meaning it bounces a large portion of sunlight off rather than absorbing it. By reducing the amount of energy that the roof absorbs, it directly cuts the heat that would transfer inward, lowering cooling loads and indoor temperatures.

In contrast, a dark-colored roof absorbs more solar radiation, turning more of that energy into heat that drives up indoor temperatures. Large window spacing doesn’t target the roof’s radiant heat transfer; it affects solar gains through openings and daylighting. Increased insulation helps reduce heat transfer once heat is already inside, but it doesn’t prevent the roof from absorbing radiant energy in the first place as effectively as using a reflective roof.