How do I choose an energy efficient window

How do I choose an energy-efficient window that will help insulate my home?

What makes an energy-efficient window? That’s one of the main questions that customers ask us. What do you look for? One of the most important features of a replacement window is its glazing system—a major component of the unit’s overall energy efficiency. Products with “clear” glass are the least efficient, while those with Low-E are much more thermally effective. The better-performing energy-efficient windows are those using Low-E glass with Argon or Krypton gas. Perhaps another efficient window product you could consider are some window coverings, this means it’ll be even more likely you reduce the heat leaving your home too. This is just one of the many ways to a more energy efficient home. If you live outside the area we serve, we recommend searching double glazing companies near me in order to find energy-efficient windows. When selecting a replacement window, make sure they have one of these energy-efficient systems:

Energy-Efficient Glazing Featuring PPG Intercept®

Harvey energy-efficient windows and patio doors feature the PPG Intercept® “Warm-Edge” spacer system. Intercept® is a unique, seamless coated steel U-channel system developed by PPG Industries which is located at the point of contact where the glass is sealed to the window frame. The U-channel spacer bar is manufactured as one continuous piece, providing excellent structural integrity and superior thermal performance. PPG Intercept® “Warm-Edge” technology also provides 10% warmer indoor glass edge temperatures and outstanding argon gas retention, a higher R-value, and excellent condensation resistance.


Low-emittance (Low-E) is a coating that increases a window or door’s ability to diminish heat transfer, thus saving heating and cooling costs. In addition to energy savings, Low-E also effectively reduces the amount of transmitted ultraviolet light which can damage carpets, fabrics, and drapes. Energy-efficient windows use Solarban® 60 Low-E Glass from PPG Industries which is ideal for any climate throughout the U.S.

Low-E/Argon Gas

Some windows combine PPG Intercept®, Low-E Glass and Argon gas between the glass for superior thermal efficiency. Argon gas is much heavier than air, making it more difficult for warm or cold air to pass through. This glazing choice will meet or exceed most local building code requirements and provides ENERGY STAR® qualified performance on your energy-efficient window.

Energy Efficient Windows

ENERGY STAR qualified Low-E/Argon Gas-Filled Glazing

Double Low-E/Argon

This top of the line glazing system utilizes Low-E coating on both pieces of glass for increased UV protection and more heat transfer resistance. Argon gas between the glass makes warm or cold air pass through more difficult, thus saving energy.

Low-E/Krypton Gas

By combining PPG Intercept®, Low-E glass and Krypton gas between the glass for superior thermal efficiency. Similar to Argon gas, Krypton gas is much heavier than air, making it more difficult for warm or cold air to pass through. Krypon gas works best in a 3/8″ air space.

ENERGY STAR Performance Ratings

When choosing a new energy-efficient window, make sure you’re familiar with the performance ratings. The NFRC label, which can be found on all ENERGY STAR qualified windows, provides performance ratings in a number of categories:

ENERGY STARU-Factor measures the rate of heat transfer and tells you how well the window insulates. The lower the U-Factor, the better the window insulates. U-Factor values generally range from 0.25 to 1.25. Find the ENERGY STAR U-Factor for your region.

Solar Heat Gain Coefficient (SHGC) measures the fraction of solar energy emitted and tells you how well the product blocks heat caused by sunlight. The lower the SHGC, the less solar heat the window transmits. SHGC is measured on a scale of 0 to 1; values typically range from 0.25 to 0.80. Find the ENERGY STAR SHGC for your region.

Visible Transmittance (VT) measures the amount of light the window lets through. The higher the VT, the more light you see. VT is measured on a scale of 0 to 1; values generally range from 0.20 to 0.80.

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