Efficient Window Cut OutI the last article we talked about whether you should you a pocket replacement window or a full replacement window. This time we are going to discuss what make a window energy efficient.

Replacement windows are one of the best ways to ensure that your home is energy efficient. When it comes to losing energy, old windows are the number one cause.

When choosing new replacement windows it is important to make sure that you research the different types of windows that are available and choose one that is energy efficient.

The question is, what makes windows energy efficient?

There are several factors that are considered when ranking the energy efficiency of a window. Energy Star is an independent program created by the United States government that offers a set of specific requirements that a window must meet in order to be considered energy efficient.

Energy Star Criteria

Any window that has the energy star label has to meet several standards and be manufactured by a partner of energy star. These windows are independently tested and certified by the National Fenestration Rating Council or NFRC.

The ratings that are set by the NFRC have been created by the Department of Energy of the United States. There are no technology requirements set by the Department of Energy. However, there are several features that are quite common in many of the windows that you will find efficient.

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Here are some of the factors that can affect the quality and energy efficiency of replacement windows.

Window Frame Material

The material of the window frame is extremely important. Is can also be a big factor in what are energy efficient windows. While aluminum frames are quite cheap, they are not the best option when it comes to energy efficiency. Fiberglass and vinyl are the materials that you will most often see being used for window frames that are labeled as being energy efficient.


When it comes to energy efficiency, single pane glass should be avoided. Double pane and even triple pane glass will be the most efficient. A low-E coating should be applied to the glass as well. This will help increase the efficiency of the window even more.

Low-E coating with triple pane glass offers one of the most energy efficient windows that are currently available. The coating will help to control the transfer of heat from both in and out as well as lower the chances of degradation.

Other Features

Low-E Glass ExampleArgon gas is another feature that you will find. Argon is a gas that is colorless and odorless and is used to fill the space between the two panes of glass in the window. This helps increase the R-value, making the window more efficient.

Intercept spacers are another important feature. These are used to seal and hold the insulated glass together.

These spacers also help reduce the condensation problems that may occur around the perimeter of the glass.

Weather stripping is extremely important when it comes to the efficiency of the window. The stripping is what helps keep both water and air from infiltrating your home.

Make sure that the weather stripping of your replacement windows goes all around the edges of each sash of the window where the master frame and sash meet.

Purchasing Energy Efficient Windows

With the information above and a bit of research you are well on your way to understanding what are the most energy efficient windows. Consider all of the features as well as the energy star rating of the window before making a purchase.

The particular climate that you live in will help determine the best energy efficient replacement window for your home.

Got a Question?

If you a question regarding anything about replacement windows please send it us via the Ask The Advisor page or you can post it right on our Facebook page. We look forward to hearing from you.

In the next post we will cover frame material for replacement windows. Pros and cons for all, plus which is right for you.

by Brian Kiernan

Educating homeowners on replacement windows and providing simple information to get them a great product at a great price done quickly by a reputable window pro.

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