Energy Star Program

Learn how to identify windows and doors that will provide the best energy efficiency and savings for your home.

ENERGY STAR Program Logo

The ENERGY STAR program for windows divides the country into four distinct climate zones to recognize the varying heating and cooling months among the states. For patio doors, there is only one U-Factor and one Solar Heat Gain Coefficient (SHGC) requirement for Energy Star compliance.

Please consult your contractor or a Lowe’s store associate for specific thermal properties that vary based on glass options and grid choices, and verify your window’s actual performance to ensure Energy Star rating in your specific climate zone.

Learn more about the ENERGY STAR program by visiting their website at www.energystar.gov.


Energy Star Requirements

Window Criteria

The chart to the right provides U-Factor and Solar Heat Gain Coefficient (SHGC) values used to determine if a window meets ENERGY STAR requirements for a given climate zone.

Energy Star Requirements

Door Criteria

The chart to the right provides U-Factor and Solar Heat Gain Coefficient (SHGC) values used to determine if a door meets ENERGY STAR requirements for a given climate zone.

Low-E and Argon Gas

Learn how Low-E coatings on glass and argon gas filled between glass panes reduces energy usage and improves the year-round comfort of your home.

Understanding Condensation

Learn more about the causes of condensation on windows in your home, as well as ways to reduce or eliminate it.

Energy Tax Credit

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

Learn More

Energy Efficient Glass

With multiple glass options to increase energy efficiency, there is a glass package to fit any climate need and budget. Visit the Glass section of our site to learn more about available options and energy efficiency.

Learn More

Windows 101 Videos

In this section you find a collection of educational videos covering a wide range of topics. Each short video is dedicated to a specific Windows 101 topic of interest.

Browse Videos

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Schedule a free, no-obligation in-home consultation with Lowe's to get ReliaBilt windows and doors for your home today.