How Much Can New Windows Lower Your Energy Bill?

Does your home still have its original, single-pane windows? Are your windows exceptionally drafty during the winter? There’s a good chance installing double-pane high-performance windows can help you cut down on energy costs.

But you’re probably wondering: Just how much will I save?

Potential savings are dependent on a number of factors. For example, the climate in which you live will affect how much you will save. In climates with long, cold winters, energy savings is more significant than updating windows in warm, mild climates. Plus, the orientation of the windows and the window’s insulating value are also major factors that can affect energy savings.

Overall, ENERGY STAR estimates that in cold-weather climates like New England, the Mid-Atlantic, and the South Atlantic, cost savings total about $425-$465 per year when single-pane windows are replaced. In the Upper Midwest and even in southern parts of the U.S., the average savings totals nearly $400 each year.

How the Window’s Insulation Value Can Affect Savings

The type of window you choose will determine how efficient it is as an insulator. Double-paned windows, for example, are much better insulators compared to single pane windows, but when comparing double-pane windows, there are two numbers you should consider: U-Factor and Solar Heat Gain Coefficient (SHGC).

U-Factor is a measure of insulation, and windows with lower U-Factor values provide better insulation. Single pane windows, for example, have an average U-Factor of about 1.05, while double-pane windows have U-Factors as low as 0.35. Ultimately, the window’s U-Factor is determined by frame material, type of fill between panes, the spacing between panes, and type of coating on the glazing.

SHGC is a measure of how effective the window is at preventing solar heat from entering the home. East- and west-facing windows, for example, receive a substantial amount of sunlight, and this solar energy can quickly increase the interior temperature of a room. This requires an increase in cooling requirements, which increases cooling costs.

Ultimately, a window with a low U-Factor and low SHGC will help you achieve the greatest energy savings in the home.  

How Orientation, Size of Windows May Affect Energy Savings

Another factor to consider: The orientation and size of the windows. South-facing windows, in particular, should have higher SHGC ratings. This allows the southern windows to collect more heat during winter, helping to offset some heating costs. In the summer, shading, window treatments, and other features can help to limit this heat from entering the home.

Windows on the east- and west-facing walls of the home should be limited in size and have greater SHGC ratings. Typically, these walls receive the most amount of sun, which can overheat the home in the summer months. Low-SHGC windows can help to limit solar radiation and strategies like landscaping and window treatments can also help to diminish the amount of radiation.

Updating your home’s windows can instantly reduce your home’s heating/cooling costs. Yet, there are many different factors that will affect how much you stand to save. Installing high-performance windows in a cold-weather climate, for example, can add up quickly in yearly energy savings. Plus, the type of windows you use, as well as their orientation to the sun, can also greatly affect how much you will save.


Matt Davis is a Writer for WeatherMaster Windows. WeatherMaster has been providing quality residential windows to Maryland, Washington D.C., and Virginia since 1986.  

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