Understanding Energy-Efficiency in Replacement Windows

Replacement windows for improved energy efficiency is one of the most popular remodeling projects undertaken by Wisconsin homeowners today.  Replacing your windows could result in energy savings of 30% or more in any region of the U.S.  Your choices for replacement windows will 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 window materials conduct heat and cold. The result is some energy loss through the window materials.  The material that loses the most heat or cold is Aluminum. Steel conducts about one-third the amount of heat and cold. Stainless steel conducts about one-third the amount of heat and cold lost with 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. 

The next consideration is about the glass in the windows.  Heat and cooling loss through glass can be reduced by adding a second pane of glass and leaving space between the panes to trap the outside air which is at a different temperature from the inside air.  These double-paned or double-glazed windows are more efficient than single panes. Double-paned 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 increases the R-value of the window from 4.0 to 4.55.  Triple-paned or triple-glazed 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.

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 need 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.