Denver Window Labels


Understanding Window Energy Performance Labels

If you’ve recently purchased new windows or are shopping around for window replacements in Denver, you may have noticed a small white label on the corner of your window. This label is known as a NFRC label. It’s purpose is to inform consumers about the energy performance of a window, which the label breaks down into four different categories: U-Factor, Solar Heat Gain Coefficient, Visible Transmittance, and Air Leakage. All windows with NFRC labels are tested and certified, the purpose of which is to allow consumers to make the best decision when comparing window options.


So what does this label mean for your home and your windows? Well, each of the four categories indicate how well the window performs under given circumstances or in different aspects. Below, we’ve provided a brief description of each category as well as an indication of what to look for when comparing NFRC labels.

  • U-Factor: A window’s u-factor determines how well the window can retain heat inside a room, which is especially important for climates that experience colder winter weather. The lower a window’s u-factor is, the better it is at retaining heat.
  • Solar Heat Gain Coefficient: The Solar Heat Gain Coefficient, or SHGC, measures how well a window rejects solar heat. The lower this number, the less heat the window absorbs and allows to be transmitted into the room.
  • Visible Transmittance: Visible Transmittance indicates how much visible light is able to transmit through the glass portion of your windows. A higher Visible Transmittance rating usually means a brighter, better lit interior.
  • Air Leakage: Air Leakage signifies how much air can enter a room through your windows. The lower the air leakage number, the better a window is at keeping out strong gusts and drafts.
  • Condensation Rating: A condensation rating is not required for manufacturers, but it is sometimes displayed on a NFRC label. The higher the condensation rating, the better a window is at resistant condensation.

Get More Information

Do you have questions about window energy performance? Looking for more information? Speak to an expert. One of our staff members will be more than happy to answer any questions you may have about replacement windows in Denver or provide you with some guidance for comparing different options.

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