Undesirable solar heat gains through windows in summer increase cooling energy usage, while useful solar heat gains in winter can decrease heating energy usage. Natural ventilation aids cooling, while unwanted infiltration increasesheating and cooling requirements. In comparison to opaque building elements, windows have a disproportionate effect on the heating and cooling requirements of a home.
Houses designed to optimize passive solar performance can utilize even more solar gain.
Natural ventilation through windows can, in some instances, substantially decrease or even eliminate the need for mechanical cooling. Last updated December 31, 1995.