The number to know when selecting windows, doors, and skylights. It's a measure of how much of the sun's heat is transmitted through those fixtures, expressed in a number from zero to one. A window that has a SHGC of .3 will allow 30 percent of the sun's heat to pass through. Whether you want a higher or lower number will depend on your goal: A product with a low SHGC will help to block heat and reduce cooling loads in hot weather; a product with a high SHGC will be more effective at harnessing solar heat in cold weather.

Top Searched Terms

Acid rain Biodegradable Carbon footprint Environmental impact Fossil fuel Global warming

Kyoto Protocol Sustainability Weatherstripping Wildlife corridor Wind energy Xeriscape