U-factor measures how well a product prevents heat from escaping a home or building. U-factor ratings generally fall between 0.15 and 1.20. Products with low U-factors are better at keeping heat inside the building.
Solar Heat Gain Coefficient (0 - 1) measures how much heat from the sun is blocked. The lower the SHGC, the more a product is blocking solar heat gain.
Visible Transmittance (0 - 1) measures how much light comes through a product. Products with higher numbers pass through more light.
Condensation Resistance (1 - 100) measures how well a product resists the formation of condensation. Products with higher numbers resist condensation better.
Qualifications by U.S. region: Northern (N), North-Central (NC), South-Central (SC), and Southern (S)
Energy Star requirements vary depending upon heating and cooling needs of a region.
Zones A, B, C, and D based on heating degree days (HDD):
Zone A: <= 3,500 HDDs (warmest)
Zone B: > 3,500 to <= 5,500 HDDs
Zone C: > 5,500 to <= 8,000 HDDs
Zone D: > 8,000 HDDs (coldest)
NFRC - NFRC.org energy ratings
Energy Star (United States) - EnergyStar.gov climate regions
Energy Star (Canada) - Canada Office of Energy Efficiency climate zone map
This tool provides some of the most common options on windows and doors and related NFRC values. For more information about the energy efficiency of specific products and options, please contact your local Integrity sales representative.
The National Fenestration Rating Council (NFRC) has developed and operates a uniform national rating system for the energy performance of fenestration products, including windows and doors. For additional information regarding this rating system, see www.nfrc.org/WindowRatings.
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