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Home | Window Styles | Energy Efficiency

If you’re dealing with poor window performance, such as drafty windows, temporary solutions like sealants and weatherstripping won’t keep your home comfortable for long. Replacement windows from Great Lakes Window will seal out unwanted cold and heat, saving you a bundle on heating and cooling costs. So while Mother Nature stays out, energy efficient windows keep you safe and sound all year-round. Our windows are built to resist the heat and cold, offering four-season comfort. Need proof? We meet or exceed the current standards for ENERGY STAR® Version 6.0 requirements in all 50 states and can exceed requirements for the Northern Zone, by up to 48% with select glass packages. Below are four common ratings that are provided for windows certified by the National Fenestration Rating Council (NFRC), the American National Standards Institute (ANSI) and the American Architectural Manufacturers Association (AAMA).

Defining Energy Performance Ratings:

  • U-Factor – A measure of the rate of heat flow through a window. Heat efficient windows have better insulating properties. A lower U-Factor indicates a higher performing window that can help reduce heating and cooling costs.
  • Solar Heat Gain Coefficient (SHGC) – The amount of solar radiation allowed to pass through a window. The lower the number, the less solar heat gain the window permits.
  • Structural-Design Pressure (DP) – The amount of wind pressure a window will withstand when closed and locked is called Structural-Design Pressure (DP). The higher the number, the better.
  • Visible Light Transmittance – Ranging from 0 – 1, visible transmittance is a measure of how much light passes through the window.

The Windows look great and we can see the a/c and heating savings already. We highly recommend this company.
– Barbara Maher

Solar Heat Gain Coefficient Visible Transmittance

In 2016, ENERGY STAR changed their ratings dictating what U-Values and Solar Heat Gain Coefficient ratings will be required in order to receive the ENERGY STAR for windows and sliding patio doors. To find out what these new ratings are, mouse over or click on your region to see the ENERGY STAR requirements for your region.

Energy Star Map

Because Great Lakes Window has ENERGY STAR windows, the National Fenestration Rating Council (NFRC) labels are printed on all Great Lakes windows.

Awarded the ENERGY STAR Most Efficient Recognition in 2023

The ENERGY STAR Most Efficient 2023 designation recognizes the most efficient products among those that qualify for the ENERGY STAR program. The Great Lakes Window ecoSmart, ComfortSmart and HarborLight windows represent the leading edge in energy efficient products this year.

Energy Tax Credit

Learn more about the 2021 Energy Tax Credit extension and download the Great Lakes Window Manufacturer’s Certification Statement.

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