ENERGY STAR Rated Replacement Windows

ENERGY STAR Rated Replacement Windows

Energy-efficient home appliances and building products can help you reduce your energy bills. Windows, which are part of the envelope of your home, play a big role in your home’s energy efficiency. In fact, the Department of Energy↗ reports that “Heat gain and heat loss through windows [is] responsible for 25%–30% of residential heating and cooling energy use.”

Learn how to save on your energy expenses with ENERGY STAR® certified windows in this quick post. 


The ENERGY STAR® program↗ was established by the U.S. Environmental Protection Agency (EPA) in 1992. The program is operated by the EPA and the Department of Energy (DOE) to provide consumers and businesses with credible and unbiased information regarding cost-saving energy-efficient solutions. 

Visit ENERGY STAR®’s website to find more information on certified products, appliances, lighting and more. Skip to the end of this post for ENERGY STAR® certification criteria for windows

ENERGY STAR® Replacement Window Ratings

There are a few ways to tell if replacement windows will meet ENERGY STAR’s criteria. The first way requires knowing what ENERGY STAR’s criteria is, ENERGY STAR Partner List↗ for Windows, Doors, and Skylights

Search Energy Star window manufacturers.

Top Rated ENERGY STAR® Replacement Windows from Brennan

Our team at Brennan Enterprises can work with you to build ENERGY STAR certified replacement windows. All of the vendors we work with are ENERGY STAR partners. 

What makes a window ENERGY STAR?

ENERGY STAR qualified windows meet the following criteria:

  1. Are manufactured by an ENERGY STAR partner
  2. Are independently tested, certified, and verified by the National Fenestration Rating Council
  3. Have NFRC ratings that meet strict energy efficiency guidelines set by the EPA. 

ENERGY STAR certified windows meet performance criteria based on certified ratings from the NFRC.

NFRC ratings from product to product. Differences in operation style, size, type of spacer, and glass package all affect NFRC ratings. ENERGY STAR provides a listing of partners and certified products online; the product listings are fairly difficult to read so we recommend speaking with a window company and asking for specific product ratings. Most companies will need to “build the window” in their quoting systems in order to provide you with the most accurate information. 

Homeowners in Texas can reach out to our team to learn about the products from the ENERGY STAR partners below. Many of the vendors on this list work with dealers nationwide so if you are outside of the Texas area you should have a local dealer near you. 

Explore our window options using the links below. 

Brennan Windows

Andersen Windows

Milgard Windows

NT Windows 

Sierra Pacific Windows

ENERGY STAR® Criteria for Windows

The materials windows are made of react differently to weather conditions. To address these differences ENERGY STAR criteria vary by climate zone. 

Use this link to find the ENERGY STAR climate zone for your location↗

Performance Criteria

Performance criteria are based on ratings from the National Fenestration Rating Council. 

Learn more about NFRC ratings: NFRC Window Ratings Explained


Climate Zone




≤ 0.27



≤ 0.30

≤ 0.40


≤ 0.30

≤ 0.25


≤ 0.40

≤ 0.25

Energy-Efficient Window Features

Many ENERGY STAR certified windows have similar features including:

Each of these window technologies can improve the window’s energy efficiency but remember, energy performance depends on the sum of all parts. Window ratings account for the whole window’s energy properties, that’s what makes NFRC ratings so valuable.

When you're ready to purchase new or replacement windows, remember to ask about NFRC ratings and whether the windows you're being offered meet ENERGY STAR criteria for your region. 


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