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What’s the Difference Between ENERGY STAR® and the NFRC?

To save on energy costs, you must look for two important labels when selecting windows and doors. ENERGY STAR®  and the National Fenestration Rating Council (NFRC) both assess these products for their energy efficiency. However, not all homeowners are aware of their differences.

Discover what makes these labels different from one another from a trusted door and window contractor.


The NFRC a third-party non-profit organization that sponsors certified rating and labeling to help you compare window, door and skylight performance. The NFRC doesn’t determine which products are good and bad, establish minimum performance standards or mandate performance levels.

On the other hand, a qualified ENERGY STAR replacement door or window is manufactured by an ENERGY STAR partner. All products are independently tested, certified and verified by the NFRC and have NFRC ratings that meet stringent energy efficiency guidelines set by the U.S. Environmental Protection Agency (EPA). While the organization doesn’t require any specific technologies, certified products typically have common features.

Performance Ratings

U-Factor – This rating refers to the amount of heat that transfers through windows and doors. Products with a lower U-factor have better insulating properties.

Solar Heat Gain Coefficient (SHGC) – SHGC measures solar energy transmission and how well a product blocks heat from the sun. The lower the SHGC, the less solar heat the window transfers.

Air Leakage (AL) – This denotes the amount of air that enters and escapes through window and door frames. This rating can change over the lifetime of the frame material as it expands, contracts or warps. Products with lower AL value have less air leakage.

Visible Transmittance (VT) – VT represents the amount of light that passes through a window. The higher the VT of a window, the more light you can get indoors.

Condensation Resistance  – This rating refers to how well a window can withstand water build-up. The higher this number is, the less likely that water will settle on the window.

For energy-efficient replacement windows and doors, turn to Renewal by Andersen® of Austin. You can count on us for the installation of your sliding patio doors, custom windows and more. Call us at (512) 298-2270 or complete our contact form to schedule a free in-home consultation. We cater to homeowners in Austin, TX, and areas around Texas.


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