The National Fenestration Rating Council, a nonprofit that rates and labels the energy performance of windows.
The National Fenestration Rating Council, known as NFRC, is a nonprofit organization that develops rating and labeling methods for windows and other fenestration products. Its label appears on many windows and lists measures such as U-factor, solar heat gain coefficient, visible transmittance and air leakage. Homeowners in Nashville see it on new windows and wonder how to read it.
We are an independent contractor and explain the label so you can compare windows fairly. We look at the numbers that matter for your home, such as U-factor for heat flow and solar heat gain for sun, and we compare them across models you are considering. We also point out that a rating describes the window itself, and good installation is what lets it perform.
Visit the official NFRC website
Measures how well a window keeps heat in or out. Lower is better.
Shows how much sun heat passes through the glass.
Shows how much daylight comes through.
Shows how much air passes through the closed window.
Labels use a common method, so comparisons are fair.
The label cannot capture how well a window is installed.
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Window Problem Checker: What Is Wrong?Pick what you see or hear from a window to get likely causes, what to do first and the service page that fits.Try it 
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No. Ratings describe the window, and installation affects how it performs in your wall.
No. We are an independent window company and are not part of NFRC. We explain what it publishes in plain language and help you apply it to your own windows.
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