Most people think that their home has energy efficient windows. Depending on when your home was built, the products used by the builder and the condition of your windows, you may indeed have energy efficient windows. However, for the majority of homes built in the northern Virginia building boom of the early 2000’s, the windows are not what they should be.

A Window Rated as Energy Efficient 20 Years Ago Rarely Meets Today’s Standards

As manufacturing and technology have changed, so has the standard for energy efficiency. Most of our region is in the North-Central Zone, as defined by That means the U-factor of a window with an ENERGY STAR® rating must be less than or equal to .30. The solar heat gain coefficient (SHGF) must be less than or equal to .40. The National Fenestration Rating Council (NFRC) is the independent organization that rates all windows. The elements that help make a window meet the standards to qualify as energy efficient windows are things like insulated frames and sashes, multi-panes of glass and Low-E glass.

How You Can Tell

If you’re not the original homeowner, you may be able to find a sticker on the windows that helps you determine the brand and model. From there you should be able to look up those windows specifications. If you can’t, you may be able to make a determination with these observations. First, are there multiple panes of glass? If you have single pane windows, they’re not energy efficient windows. Second, grab a match or lighter. Hold the flame up to the window pane. If you have two panes of glass, you should see the flame reflected four times. If one of these flames should be brighter and a slightly different color you likely have Low-E glass. If they’re all the same, you likely don’t have Low-E glass in your windows. (Triple pane windows reflect back 6 flames and one should be different.) Finally, touch the window sash and or frame on a cold day. Is it transferring the cold through the sash or frame? If so, you likely don’t have very energy efficient windows.

Call Peak Windows & Siding for a Free Replacement Window Quote

Although your new windows won’t pay for themselves in energy savings (don’t hire a window company who says they will), you’ll see significant savings on your heating and cooling costs. Call us today at (703) 468-4769 and we’ll help you find the style windows that fit your budget and meet your energy efficiency goals. You can also fill out our contact form and we’ll call you.

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