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The Difference Between ENERGY STAR® and NFRC

When looking for the best windows that fit your home, you need to take note of the labels that come with them, particularly the ENERGY STAR® and NFRC labels. They display important information telling you about the energy performance of the window products you’re buying. Renewal by Andersen® of Rapid City explains the difference between the two. 

The Difference Between ENERGY STAR® and NFRC


Windows, doors and skylights with an ENERGY STAR label mean they are manufactured by an ENERGY STAR partner. They are independently tested, certified, and verified by the National Fenestration Rating Council or NFRC to meet the requirements set by the U.S. Environmental Protection Agency or EPA. 

To make ENERGY STAR-qualified windows, manufacturers make sure they have multiple panes, warm edge spacers, gas fills, low-emissivity glass, and quality frame materials. For framing materials, ENERGY STAR provides a wide variety. For instance, fiberglass frames are durable and provide good insulation, while aluminum frames are recyclable and typically have at least 15% recycled content. On the other hand, combination frames use different materials separately throughout the frame to provide optimal performance. An example of this would be our exclusive Fibrex® frames, which combine the natural beauty of wood with the low-maintenance qualities of vinyl.

What Is NFRC?

NFRC is a third-party non-profit organization that provides rating and labeling to help homeowners compare the optimal performance of windows. However, it’s important to note that NFRC does not mandate performance levels or distinguish between “good” and “bad” windows. Instead, ENERGY STAR enables consumers to identify the NFRC-certified windows with excellent energy performance. 

Moreover, NFRC usually lists five measurements:

  1. U-Factor – It measures the rate of heat transfer and determines how your window insulates. The lower the number, the better an insulator the window is. 
  2. Solar Heat Gain Coefficient (SHGC) – It measures the fraction of solar energy that travels through your window and refers to how well the product blocks heat caused by sunlight. The lower the number, the less solar radiation is allowed. In warm climates, be sure to seek the lowest possible SHGC to minimize air conditioning. By comparison, a slightly higher SHGC is ideal for cooler climates to heat your home in winter. 
  3. Air Leakage (AL) – It measures the rate at which air passes through your window. The lower the number, the more airtight the window. However, ENERGY STAR standards don’t consider air leakage as it’s difficult to measure accurately and may change over time. 
  4. Visible Transmittance (VT) – It measures the amount of light your window allows. A low number means the room will be dim, while a high number means the room will be bright. VT and SHGC are basically the same with older window glazing techniques, but new technologies made it possible to let in lots of light while the room stays cool. 
  5. Condensation Resistance – It measures how well your window resists water buildup. The lower the number, the more condensation the window allows. 

For more inquiries regarding your window needs, look no further than Renewal by Andersen of Rapid City. Our window experts are more than glad to assist you with your installation needs. Call us today at (605) 341-7831 or fill out our contact form to set an appointment. We proudly serve homeowners in Rapid City, SD, and the surrounding communities.


"The Andersen crew was very prompt and professional, and was finished in 1 day. Great!"

Terri Vaughn
May 10

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