SHGC: What Solar Heat Gain Coefficient Means for Your Windows
SHGC (Solar Heat Gain Coefficient) measures how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window, both directly transmitted, and absorbed and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window’s SHGC, the less solar heat it transmits.
Blocking solar heat gain is particularly important during the summer cooling season in hot Southern climates. By contrast, people in Northern climates may want solar heat gain during the cold winter months to lessen the cost of heating the home.
How to choose SHGC for your climate
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Hot, sunny climates (Florida, Texas, the Southwest): choose a low SHGC to keep cooling costs down.
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Cold climates: a higher SHGC on south-facing windows lets the winter sun help heat the house.
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Mixed climates: many projects use different glass on different sides of the building.
SHGC of our windows
Our aluminum systems are available with SHGC from 0.16 to about 0.30, depending on the glass. Solar control and toned glass lower SHGC further. See glass options.
SHGC, U-factor and visible transmittance together
A low SHGC usually also lowers visible light (VT). Ask us for the combination that fits your design, and read window specifications explained.
Window performance guide