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The Differences Between the ENERGY STAR® and NFRC Labels

When shopping for replacement windows or doors, you’ll come across the blue-and-white ENERGY STAR® label on various products. This signifies the products’ adherence to stringent energy efficiency performance standards set by the U.S. Department of Energy (DOE) and the Environmental Protection Agency (EPA). In addition, you’ll probably see another label from the National Fenestration Rating Council (NFRC).

What do these labels mean? Read on as we highlight the differences between these two important indicators of energy efficiency.

About the ENERGY STAR Label

Products with the ENERGY STAR label have met certain energy efficiency standards. To earn the ENERGY STAR label, a product has to be manufactured by an official ENERGY STAR partner. In addition, it must have been independently tested, certified and verified by the NFRC. Finally, the NFRC ratings used to indicate the product’s energy performance must meet strict energy efficiency guidelines set by the EPA.

About the NFRC Label

The NFRC label allows customers to compare energy-efficient fenestrations. Found on all ENERGY STAR-certified windows, entry doors and French doors, the NFRC label shows the product’s energy performance ratings in the following categories.:

  • U-Factor – This measures the rate of heat transfer and tells you how well the window or door insulates. The values range from 0.25 to 1.25. A lower U-factor value means better insulation.
  • Solar Heat Gain Coefficient (SHGC) – This measures the fraction of solar energy transmission and tells you how well the window or door blocks the sun’s heat. The SHGC of windows and doors often ranges from 0.25 to 0.80. The lower the SHGC value, the less solar heat the product transmits.

ENERGY STAR qualification is based on these two categories. Other categories in the NFRC label that are of similar importance are air leakage, visible transmittance and condensation resistance.

Renewal by Andersen® of Austin can help you choose the best windows and sliding patio doors to improve your home’s energy efficiency. Call us today at (512) 298-2270 or fill out our contact form for a virtual consultation. We serve homeowners in Austin, TX, and nearby areas.


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