Solar Heat Gain Coefficient (SHGC)

A window’s Solar Heat Gain Coefficient (SHGC) is a measurement of the amount of heat that passes through it from direct sunlight and absorbed heat. A smaller Solar Heat Gain Coefficient indicates a greater ability to resist heat gain.

The increased temperature within a building caused by solar heat gain can be either positive or negative, depending on the circumstances. For example, heat gain from sunlight would be beneficial in colder climates, reducing the amount of energy needed for heating the room. In warmer climates, however, heat gain would increase the energy needed to keep the room cool.