How to Choose an Energy Efficient Window

We’re all looking for ways to save money, especially with recurring expenses like our energy bills. Installing energy efficient windows is one way to save money because they reduce your need for heating or cooling. Selecting energy efficient windows is a breeze.

Just select windows that:

  1. Meet local energy code requirements
  2. Are ENERGY STAR® qualified

How can you tell if a window meets local energy code requirements? Well, most municipalities adopt a version of an energy code that aligns with its climate zone, specifying a maximum U-Factor, the rate of heat transfer and how well a window insulates. So all you need to do is look for windows within that magic maximum U-Factor range.

How can you tell if a window is ENERGY STAR® qualified? ENERGY STAR® is a U.S. Environmental Protection Agency qualification program. Windows with this qualification have an ENERGY STAR® label which confirms they meet window energy efficiency standards based on U-Factor and Solar Heat Gain Coefficient ratings (more about this rating below). All ENERGY STAR® qualified windows are National Fenestration Rating Council (NFRC) certified and carry the NFRC label.

What information does the NFRC label display? This comprehensive label displays information that enables you to make an informed decision about an item that will stay in your home long after you’ve moved. The NFRC certifies windows based on these criteria:

  1. U-Factor — The rate of heat transfer as well as how well a window insulates (expressed as a number between 0.15 to 1.20). The lower the number the greater a window’s resistance to heat loss.
  2. Solar Heat Gain Coefficient — The amount of heat from the sun that is blocked (expressed as a number between 0 and 1). The lower the coefficient, the more solar heat gain is blocked.
  3. Visible Transmittance — The amount of visible light transmitted through a window (expressed as a number between 0 and 1). The higher the number, the more the window maximizes daylight.
  4. Air Leakage Rating — The measure of heat loss and gain around a window (expressed as a number between 0.1 and 0.3). The lower the number, the less air that will pass through the cracks in the window.
  5. Condensation Resistance — The measure of how well a window resists the formation of condensation inside of it (expressed as a number between 1 and 100). The higher the number, the better the window is able to resist condensation.

As you consider energy efficient windows, also research local, state and federal economic incentives that may be available for installing them. These incentives will help you save even more money.

Photo credit: Getty Images

About the Author

Monica D. Higgins is a remodeling expert who prevents and protects homeowners not looking to do the work themselves, from budget overruns to construction delays and shady contractors. Higgins's proven process and expert knowledge has been featured by HGTV, DIY Network, "Entrepreneur Magazine," Lowe's for Pros and