Before you shop for energy-efficient windows, doors, and skylights, learn about energy performance ratings. | Photo courtesy of iStockphoto.com/JamesBrey.
You can use the energy performance ratings of windows, doors, and skylights to tell you their potential for gaining and losing heat, as well as transmitting sunlight into your home.
ENERGY PERFORMANCE TESTING, CERTIFICATION, AND LABELING
The National Fenestration Rating Council (NFRC) operates a voluntary program that tests, certifies, and labels windows, doors, and skylights based on their energy performance ratings. The NFRC label provides a reliable way to determine a window’s energy properties and to compare products.
The NFRC label can be found on all ENERGY STAR® qualified window, door, and skylight products, but ENERGY STAR bases its qualification only on U-factor and solar heat gain coefficient ratings, which are described below.
HEAT GAIN AND LOSS
Windows, doors, skylights can gain and lose heat through:
- Direct conduction through the glass…
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