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Energy Star Certification

Last updated on 05/19/2022

As winter comes each year you may be dreading the arrival of your heating bill, alternatively, each summer you may dread your cooling bill. You may be struggling to keep those bills affordable. But did you know there’s a better way to keep your home comfortable and your bills low?

Replacing your windows with ENERGY STAR rated windows can be a great way to save money and make your home more efficient. Read on to learn more about these windows and how they earn the coveted ENERGY STAR certification.

Manufacturer Credentials

There are three primary criteria windows need to meet in order to get an ENERGY STAR rating, the first of which is manufacturer credentials. ENERGY STAR has certain partner companies that have been examined carefully. These companies have proved that they use manufacturing standards that guarantee energy-efficient products.

There are currently 513 product manufacturers who have been confirmed as ENERGY STAR partners. These companies are a good place to start, but be sure to check the credentials on the specific windows you wind up selecting.

The Energy Star Label

Tests and Certifications

Energy-efficient windows must also pass certain tests and certifications. The National Fenestration Rating Council has several different certifications that products can earn. An ENERGY STAR rated window must be independently tested, certified, and verified by the NFRC.

It’s important to note that the NFRC doesn’t rate windows as being “good” or “bad,” and they don’t have minimum performance requirements. Instead, the EPA sets minimum ratings and certifications products must earn from the NFRC. The NFRC simply provides an independent, unbiased review of the windows.

NFRC Ratings

So what evaluations does the NFRC use, and what ratings pass the EPA requirements for ENERGY STAR certification? The NFRC looks at five different factors in window performance: u-factor, solar heat gain coefficient (SHGC), air leakage, visible transmittance, and condensation resistance. You can find each of these ratings on any product the NFRC evaluates.

U-factor tells you how well the window insulates against heat transfer and usually ranges from 0.25 (best) to 1.25 (worst). SHGC tells you how well the window blocks heat from sunlight and ranges from 0.25 (best) to 0.80 (worst).

Air leakage evaluates how much air is passing through the window. It must remain below 0.3 cubic feet of air passing through one square foot area of window per minute.

Visible transmittance measures how much light you can see through the window and ranges between 0.2 (least) and 0.8 (worst). Condensation resistance tells you how well the window keeps water from building up and ranges between 0 and 100, with 100 being the best.

Different Climate Zone Requirements

The EPA has different requirements for products to gain ENERGY STAR certification depending on where you live. Southern states have to have a better SHGC rating, but can have a higher U-factor. Northern regions can have a higher SHGC, but must have a lower U-factor.

Southern region requirements: U-factor no higher than 0.4, SHGC no higher than 0.25.

South-Central region requirements: U-factor no higher than 0.3, SHGC no higher than 0.25.

North-Central region requirements: U-factor no higher than 0.3, SHGC no higher than 0.4.

Northern region requirements: U-factor no higher than 0.27, any SHGC.

How They’re Built

Energy-efficient windows all tend to have a similar design that gives them the insulating properties they need. These windows start with a quality frame that reduces heat transfer and provides excellent insulation. They may also have warm edge spacers that insulate pane edges, keep glass panes spaced appropriately, and reduce heat transfer.

The best ENERGY STAR rated windows have multiple panes of glass separated by a gas-filled middle space. This helps to reduce both heat transfer and sound insulation, especially if they’re filled with gases like argon or krypton. Glass in these windows also has a special coating that reflects infrared and ultraviolet light.

Savings from Replacing Windows

It will come as no surprise that replacing your windows with ENERGY STAR rated windows will save you money. How much you can save will depend on where you live and whether you’re replacing single- or double-pane windows.

If you live in the Northern region of the U.S. and you replace single-pane windows, you could save as much as 22 percent on your heating and cooling bills. People in the North-Central zone could save up to 20 percent. People in the South-Central and Southern zones could save 31 percent or more.

If you replace double-pane windows in the Northern zone, you could save up to 9 percent on heating and cooling bills. In the North-Central zone, you could save 8 percent.

In the South-Central zone, you could be looking at up to 14 percent savings. People in the Southern zone could save a whopping 17 percent on their bills by replacing their double-pane windows.

Discover the Benefits of ENERGY STAR Rated Windows

ENERGY STAR rated windows are a great way to make your home more efficient, save on bills, and reduce your environmental impact. Windows have to meet a few different EPA criteria in order to earn the ENERGY STAR certification. Depending on your current windows and where you live, you could save almost a third on your heating and cooling bills just by making this switch!

If you’d like to discover the benefits of ENERGY STAR rated windows for yourself, check out the rest of our site at Window Joe Replacement Windows. We provide support to homeowners in selecting replacement windows and replacement window installers. Check out our guide to different types of window replacements today and start saving on replacement windows.

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