Understanding Window Energy Efficiency | DC Complete

Windows are an important consideration when building a new home or addition. And when it comes time to replace windows in an existing home, homeowners would do well to understand the types of replacement windows available to them. Aside from the style of window and how they will look aesthetically, an equally important consideration is the level of energy efficiency your new windows provide. According to the U.S. Department of Energy’s Office of Energy Efficiency & Renewable Energy, “Heat gain and heat loss through windows are responsible for 25%–30% of residential heating and cooling energy use” – not an insignificant factor. Your objective, then, should be to install windows that will provide the best energy efficiency in the climate where you live, as not all windows are created equal.

One factor that contributes to the energy efficiency of a window is the frame, which can be wood, aluminum, vinyl, or wood-clad. Wood window frames provide good insulation, as they do not allow as much heat or cold to transfer as do metal frames, such as aluminum. High quality wood frames will last a long time, but in damp, humid climates, they may be prone to rotting and, therefore, require more maintenance.

Aluminum frames, in spite of their heat transfer characteristic, are a good choice in climates that are humid and rainy. Additionally, they are strong enough to hold up to hurricane-strength winds. Vinyl also performs well in terms of energy efficiency and is typically less expensive than other types of window frames. Wood-clad windows provide an exterior that is low maintenance, as either vinyl or aluminum is used to encase a wood interior frame. Water can seep into these frames, however, and lead to wood rot, so they are better indicated for dry climates.

Another important factor in ensuring energy efficient windows is the type of glass used. Windows can be single-paned, double-paned, and even triple-paned. To make a real difference in your utility bills and get the best insulation, you should minimally consider thermal, double-paned windows over single-paned. They should be Low-E (low-emissivity), argon-filled windows, which protect the house from the summer sun’s heat and UV rays on the inside while also preventing inside heat from escaping to the outside in winter.

You can easily find out the efficiency level of the glass in windows you may be considering by checking the Energy Star sticker on the window. The sticker contains the rating by the National Fenestration Rating Council (NFRC), which determines the Energy Star status of the glass. Specifically, you will find the window’s U-Value, which indicates how much heat escapes from the house. This value can be a range of .20 to 1.20. The Solar Heat Gain Coefficient (SHGC) indicates how much heat enters a home. Lower numbers indicate better energy efficiency performance.

Sufficient insulation and proper installation are also critical components to making sure your new or replacement windows are as energy efficient as they can be. Make sure you select a builder or contractor who is experienced and qualified to help you select your windows and install them.

Of course, in lieu of replacing windows altogether, homeowners can improve the energy efficiency of their windows by taking a few simple steps, such as adding storm windows, caulking or weatherstripping leaks, applying a protective film coating to windows, and hanging awnings or overhangs outside and using window treatments that are designed to improve energy efficiency inside.

If you are looking to install new or replace existing windows and would like to learn more about window options, contact Sovereign Construction Services. Owner Steve Rush is knowledgeable about all window types and the installation process, and is available to share his expertise and answer all your questions.

For answers to all your remodeling questions, call DC Complete at (810) 407-1771.