Reduce costs with energy efficient windows

This window obviously has a low Condensation Resistance, causing moisture and even ice to form. (Photo courtesy of Angie’s List member Jenny G. of Milwaukee)

This window obviously has a low Condensation Resistance, causing moisture and even ice to form. (Photo courtesy of Angie’s List member Jenny G. of Milwaukee)

As a homeowner, you're looking for all sorts of ways to save money, and decreasing your home's heating and cooling expenses is one way of doing just that.

One of the most effective ways to improve a building's energy efficiency is to capitalize on the energy benefits of replacement windows. If you already plan to replace your windows for some other reason, you have an excellent opportunity to make them energy efficient as well.

If you're concerned that the price tag on these windows will bust your budget, rest assured that the energy benefits of replacement windows can help recoup some of those costs over time. There are other ways to make them more affordable, too. For example, you can replace them slowly over time as funds become available, or all at once when tax credits and financing may be offered.

Where to start

How much you may actually save in dollars and cents depends on a variety of factors. As the best place to begin, learn about windows in general, familiarize yourself with how they function and investigate which ones are most appropriate for your house.

Learning about proper installation is critical because misfitting windows can cause energy loss. Rely on Angie's List to identify reputable installers in your area from perusing member experiences from reviews and ratings.

You should also figure out whether you'll be replacing the entire window frame, only the windows and sash or the just the windows themselves. These considerations will play a major role in determining how much to budget. With these decisions made, you can then look at the showrooms and websites of different window manufacturers for design choices.

Follow the star

When you're ready to shop, look for the Energy Star label. Under the Energy Star program, the U.S. Department of Energy and the Environmental Protection Agency have divided the nation into climate zones. Energy Star windows for your specific zone may qualify you for a 10 percent federal tax credit on the purchase cost of the actual windows, excluding the cost of installation. In addition to the federal incentive, various localities and utility companies offer assistance as well, primarily through financing assistance.

The whole window

Another label to look for is that of the National Fenestration Rating Council (NFRC). This label will provide information about "whole window" energy factors. As the name implies, a window's entire energy value is expressed in several values, including the following:

  • U-factor measures heat loss; windows with a lower U-factor are ideally suited for cold climates.
  • Solar Heat Gain Coefficient (SHGC) measures how much heat from sunlight passes through the window; windows with a low SHGC are better suited to warmer climates.
  • If you've ever sat beside a drafty window, it has had a high Air Leakage (AL) factor.
  • The higher a window's Condensation Resistance (CR), the less likely you are to see water condensing within multiple window glazes.
  • Visible Light Transmittance (VT) is akin to sunglasses: the higher the number, the less visible light that passes through the window.

A window's U-factor and SHGC determine its eligibility for the federal tax credit. Energy efficiency of a window is also affected by an invisible protective layer called E-coating. Argon or krypton gas sealed between each layer further enhances the efficiency of multiple glazed windows. Various configurations of these factors determine the Energy Star rating and thus the most energy efficient window for your home.

Other factors

Keep in mind, however, that a window's efficiency is also determined by, among other things, your local climate, the orientation of your home, the size and location of the windows, the method you use to heat and cool your home and the degree of shading around the house. You can plug these variables into a free, downloadable computer program called RESFEN, and the results will help you better understand how these factors can help you save money.

  • The word fenestration means the design and placement of windows and other openings on the outside of a building and derives from fenestra, which is Latin for window.

More Like This

5 window efficiency terms explained


Your contractor should be able to help you pick the right windows for your home. (Photo courtesy of Angie's List member Clayton B.)
Your contractor should be able to help you pick the right windows for your home. (Photo courtesy of Angie's List member Clayton B.)

The terms used to describe window efficiency can be confusing. Understanding these terms can help you pick the right windows for your home. Ratings show how well windows resist heat transfer, reduce drafts and prevent moisture buildup.

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