Keep Your Home Energy Efficient June 27, 2013 The most effective strategy for improving household energy efficiency is to first target your home’s ‘envelope’—walls, attic, windows, and doors. Builders often refer to the exterior of a home as the “envelope” or the “shell.” Sealing the envelope or shell against air infiltration (air leaking into the house from outside) and air exfiltration (air leaking from inside the house to the outside) helps reduce your energy expenditure for space heating and cooling. Then you’ll want to improve the energy efficiency of the home’s systems, such as heating, cooling, lighting, and appliances. Builders often refer to the exterior of a home as the “envelope” or the “shell.” Sealing the envelope or shell against air infiltration (air leaking into the house from outside) and air exfiltration (air leaking from inside the house to the outside) helps reduce your energy expenditure for space heating and cooling. Without a doubt, upgrading your home’s windows and doors to energy-efficient alternatives is a good idea. Changing from drafty single-pane windows to energy efficient windows will save a lot of heating energy in a climate where winters are cold. Where summers are hot, energy efficient windows will also save significant electricity by keeping the house cooler through invisible low-E coatings on the glass. Of course, it’s important to realize that savings may not be seen immediately—it can take some time to recoup the money that you’ve spent. Windows don’t typically have as quick a payback as energy-efficient lights or cheaper air-sealing measures, for example. However, windows often endure for decades, so durable, energy-efficient windows are a very valuable investment. If your windows or doors are damaged, replacing them is a better option, unless the repair is quick and easy. When replacing, you get to choose from incredible new designs, as well as environmentally friendly and energy-efficient choices. New exterior doors often fit and insulate better than older types. If you have older doors in your home, replacing them might be a good investment, resulting in lower heating and cooling costs. If you’re building a new home, you should consider buying the most energy-efficient doors possible. In regions with cold winters such as Canada, windows should keep heat where it belongs: indoors. That means you should look for windows that slow the transfer of heat, a performance measured by the U-Factor. The lower the U-Factor, the lower the rate of heat loss through a window. In cold regions, your windows also can help you take advantage of solar radiation, which is free heat that eases the workload of your furnace or other energy-powered heat source. A window’s performance in this regard is measured by the solar heat gain coefficient (SHGC). A higher number means a window will allow more heat to pass through. When you understand how to make your home more energy efficient, you’ll be able to make the right choices to maximize the efficiency of your home’s ‘envelope.’