In an existing home, any renovation or window replacement project is an opportunity to improve your home’s energy performance. Most existing homes have poorly insulated, leaky windows that would be cost effective to replace. When replacing windows, consider increasing the windows on the south side of your home and decreasing the windows on the north, east, and west sides.
Also, look for opportunities to increase the use of natural sunlight in your home, because this reduces your energy costs for lighting. Although windows are one part of natural lighting, you might also consider eliminating unnecessary internal walls to create a more open space in your home. This allows the sunlight to penetrate deeper into your home, creating a brighter, more comfortable living space. Dividing walls that don’t reach to the ceiling can be used to provide some structure while still maintaining an open environment. The use of light-colored paints with a matte finish will help reflect and diffuse the sunlight throughout your home.
Renovations offer options to not only improve windows and lighting, but also to add heat-storing materials in areas warmed by the winter sun. In homes where it’s difficult to make use of solar energy, you might even consider adding a sunspace.
Although many of the choices for enhancing the solar energy performance of your home are straightforward, based on the concepts presented here, sometimes the correct approach is not so obvious. For instance, if you live in a climate that’s both hot in the summer and cold in the winter—as is most of the United States—and you’re not able to add overhangs to your south-facing windows, would it be better for them to admit or reject solar energy? Or if you’re totally renovating the south side of your home, what would be the ideal amount of windows?
For questions such as these, there are many computer programs available, from the very simple to the extremely complex. The U.S. Department of Energy developed one of the easier programs to use, called RESFEN, which is available free of charge. The program helps you examine the energy performance of windows in your home.