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Key Metrics to Use in Assessing Whole-Window Performance

Your windows play a key role in keeping your home looking fresh and beautiful. More importantly, they contribute significantly to improving your home’s energy-efficiency. Nowadays, homeowners pay attention to how well their windows and doors perform. With that said, what are the key metrics you should pay attention to in assessing your whole-window performance? Renewal by Andersen® of Long Island discusses more.

Key Metrics to Use in Assessing Whole-Window Performance


This refers to how good the insulation property of your windows is. It’s used to measure the amount of heat loss of a window assembly. The lower the U-factor, the greater your window’s resistance to heat flow is and signifies its great insulation properties.

Solar Heat Gain Coefficient (SHGC)

Solar heat directly indicates just how energy-efficient your windows and French doors are. The SHGC is used to measure how much solar heat goes through your window, absorbed, then released inward. The SHGC is measured from a range of 0 to 1. The lower the SHGC, the less the amount of solar heat it transmits and transfers in your home.

Air Leakage (AL)

Old, deteriorated windows are among the leading causes of poor energy efficiency. Air leakage is expressed as a cubic foot of air that passes through the gaps in the window assembly. The lower the air leakage, or AL rating, the lesser air that passes through the windows. A great benchmark for this metric is if the AL is anything below 0.30. This means that your window doesn’t let too much air leak that would cause any significant energy loss.

In need of new windows or sliding patio doors? Trust in Renewal by Andersen® of Long Island! We offer the highest quality of windows and doors on the market. You can count on us to do the job with a respectful approach and professionalism that you’d expect from the industry leaders. Call us at (631) 843-1713 or fill out our contact form for a FREE consultation! We serve customers in the Long Island area!


"I was very impressed with Renewal by Andersen. They showed up in time and we received several follow up phone calls as the installation was being done as well as the sales representative stopping by to check in on the installation. The delivery/ installer was very professional. I would highly recommend Renewal By Andersen."

February, 18

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