Deciphering Those Performance Stickers on Home Windows

Have you ever noticed that appliances and building materials often come with stickers that contain performance measurements? Not only are those ratings important for things like energy-efficiency, but they also matter for possible tax credits. Here is what you need to know about the different window performance sticker ratings as well how you can use those figures to choose the right window for your climate.

NFRC Certified

When you look at a window sticker, it should be NFRC Certified. This means that the National Fenestration Ratings Council (NFRC) has licensed the window’s manufacturer and certified the performance of the window according to the organization’s guidelines. NFRC certification will show in the top left corner of the window’s sticker, and the upper right corner will list the window’s manufacturer, style and model, and construction materials used.


One the most important ratings for any home window is its U-Value. A window’s U-Value, sometimes referred to as a U-Factor, is the rate at which the window transfers non-solar heat. In short, this measurement tells you the quality of the window’s insulation. U-Values range from 0.20 to 1.20, and usually, a lower U-Value is the best.

Solar Heat Gain Coefficient (SHGC)

Another important rating is a window’s Solar Heat Gain Coefficient (SHGC). This rating tells you how much solar heat is going to enter your home once it reaches the window’s glass. SHGC ratings range from 0 to 1, with lower ratings indicating that less solar heat will enter the home. Most people look for an SGHC rating of 0.3 or less for an energy-efficient window that will help reduce the cost of A/C.

Visible Transmittance (VT)

If you’re looking for windows that provide the most insulation, you should also pay close attention to a third rating called the Visible Transmittance (VT). The window’s VT value tells the amount of visible light that comes through the window. Most double and triple-glazed windows have a VT value that ranges between 0.30 and 0.70, with lower VT values often coinciding with lower U-Values. In some cases, you should avoid a window that a VT value under 0.40 because your visibility may suffer.

What are the Best Energy Ratings for Your Home?

Now that you know what those performance sticks on a window mean, how do you use those ratings to choose the right windows for your home? What is considered the perfect window for a northern climate may not be the most efficient for a home in the south. To find the best window, it’s important to consider both your area’s climate as well as your personal preferences.

If you live in a colder climate, you want a window with a lower U-Value (0.30 or less) and a bit higher SHGC (0.30 to 0.60), which will allow the sun’s heat to warm your home. On the other hand, if you live in a warmer climate, a lower U-Value (0.30 or less) will keep your home insulated, and a lower SHGC (0.03 or lower) will block unwanted heat from the sun from entering your home. Also, consider your personal comfort and preferences when you choose windows.

Now that you are ready to be an informed consumer, don’t forget that your home’s new windows can create efficiencies that will save you a significant amount of cash on energy bills. You may also qualify for tax savings depending on the program or tax credits available each year. Even without tax savings, new windows often pay for themselves due to the boost in energy efficiency, provided you select the correct ones for your climate.