Solar radiation reaches the Earth's surface partly as visible light, and is absorbed as heat energy by the surfaces that it strikes. Buildings conduct and radiate this heat into the building spaces that they cover through their walls and roofs. The color of the surface influences the amount of visible light reflected by it, and hence the amount of heat absorbed; for example, white or light colored walls reflect the incident visible light, and therefore, a smaller percentage of the heat energy is absorbed by them. The principle of using white rooftops or coating surfaces in light- or nearly white-colored materials, minimizes heat gain through exposed roof surfaces of buildings.

White rooftops scatter a percentage of visible light back into the atmosphere without converting it into ...