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Thermal Windows, Inc, Windows, Tulsa, OK
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What Is An ENERGY STAR® Qualified Window?

ENERGY STAR qualified windows meet a stringent energy efficiency specification set by the Department of Energy and have been tested and certified by the NFRC (National Fenestration Rating Council). The NFRC is an independent, third-party agency that maintains a database of certified window and door energy performance information. The information includes U-factor, SHGC (Solar Heat Gain Coefficient), VT (Visible light Transmission) and other data.

ENERGY STAR qualifications are based on U-factor and SHGC ratings for each of four different climate zones (see map below). To be ENERGY STAR qualified, a window or door must meet the efficiency standard for the climate zone where it will be used.

Energy Star Zone Map

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Did you know: There is no ENERGY STAR certification for commercial windows. ENERGY STAR applies only to residential windows and doors. Click here for details.

For more information, call us toll-free at (800) 259-7580 or visit the U.S. Department of Energy's
ENERGY STAR website:

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