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Energy-Efficient Windows: Terms You Need to Know

While you may know exactly the style of windows or patio doors you want for your home, finding the most energy-efficient ones can be daunting given the confusing terms and the various options available on the market. As a homeowner, understanding the components of these high-quality products is imperative. Continue reading as we provide essential information about energy-efficient windows and doors.

Energy-Efficient Windows

Insulated Glass

To begin with, the term “insulated glass” is a misnomer. It comes from the fact that the windows have two or more glass panes separated by insulation at the edges. The space created by the panes is filled with air to enhance the windows’ thermal efficiency.

Gas Fill

During the early years of double glazing technology in windows, manufacturers first filled the spaces between the panes with air, carbon dioxide and Freon. Inert gases came decades later and became the standard for energy-efficient windows today. Those filled with argon, in particular, became widely popular because of how it contributes to the product’s overall thermal performance.

Low-emissivity Glass Coatings

Windows and doors have special coatings applied on the exterior and interior of the glass to reduce the amount of ultraviolet and infrared light passing through them without sacrificing visible light. Thanks to the added thin layer of metallic oxide, the coatings help reflect these unwanted light wavelengths from the glass surfaces. Low-emissivity glass helps preserve your windows’ beauty and performance, protect your home’s interior from fading, and save you money on energy bills.

Energy Performance Ratings

The effectiveness of energy-efficient windows is based on energy performance ratings set forth by the National Fenestration Rating Council (NFRC). These include the solar heat gain coefficient (SHGC), U-factor, visible transmittance and air leakage. The ratings for each vary depending on your region’s climate.

At Renewal by Andersen® of Long Island, we offer premium quality replacement windows, French doors and sliding patio doors that are engineered to be energy-efficient, helping you save money on heating and cooling costs all year long. Give us a call at (631) 843-1713 or fill out our contact form to schedule a consultation. We serve homeowners in Long Island and the surrounding communities.


"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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