What You Should Know About Energy Efficient Replacement Windows

Replacement Windows from Tollefson Bros. Bloomington, MNEnergy efficient replacement windows are one of the most popular home improvement projects that you can complete today. There is now so much new technology to make windows more energy efficient that your new windows could result in energy savings of 30% or more in our Minnesota climate.

When choosing your replacement windows, consider the style of the window as well as the efficiency and safety of the window. To help you understand the energy-efficiency qualities of various replacement windows, here are some facts to help you make decisions.


Some materials used to construct replacement windows conduct heat and cold. The result is some energy loss through the window replacement material. The replacement window material that loses the most heat or cold is Aluminum. Steel conducts about one-third the amount of heat and cold as aluminum, while stainless steel conducts about one-third as much as steel. The most efficient material for windows is wood, conducting 1/1000 the amount lost through aluminum. And just a fraction behind wood is vinyl.

The bottom line is that the most energy-efficient window materials are wood and vinyl. Vinyl, of course, requires less maintenance.


Compare Single to Double Pane Windows from Tollefson Bros. Bloomington, MN

The next consideration when it comes to the energy efficiency of replacement windows is the glass. Glass, by itself, is not an efficient barrier between temperature differences outside and inside. When you are trying to cool your house in the summer, the heat from outside is conducted through the glass and passes indoors which means more energy is required to keep your house cool. The same is true in the winter, but in reverse.

Heat and cooling loss through window glass can be reduced by adding a second pane of glass, creating an air space between the panes. Air is a much more efficient insulator than glass and you will experience a significant improvement in window performance simply by adding a second pane of glass. Nearly every manufacturer of replacement windows goes one step further and offers triple-pane windows that have two air spaces and even more insulating efficiency than dual-pane windows.

Gas Filling

Double- and triple-paned replacement windows can also have a fill of gas between the panes to further reduce heat exchange. Filling the space between panes of a double-paned window with Argon gas will make it twice as effective. Filling the space between the panes with Krypton gas further increases the R-value of the window. Triple-paned windows filled with Argon gas have an R-value of 6.25, and choosing a triple-paned window filled with Krypton gas provides an R-value of 10.0.

Replacement windows can also be coated with screening finishes of various kinds to block UV (Ultraviolet) rays and IR (infrared) rays. These screening finishes protect window treatments and furniture and carpeting from fading and reflect back some of the heating effect of the sun.

Windows of any style, size and shape can be chosen in several colors of vinyl and can be painted any color if your choice of window material is wood. Windows can be purchased with various styles of dividers within the window and even with blinds attached in enclosed compartments or with blinds placed within the window itself.

No matter what style or type of window you choose for an energy-efficient window replacement project, you will do well to look for the “Energy Star” seal first. These windows will meet minimum standards established by the Federal Government.

Tollefson Bros. Exteriors has served Minneapolis and Twin Cities homeowners from their location in Bloomington, MN for over 20 years. We are a locally owned and operated exterior home remodeler specializing in roofing, siding, gutters, and windows. Give us a call at 952-881-2218 or click here for a no-obligation FREE ESTIMATE on your project.