Window replacement strictly for energy savings carries a big price tag that can be well out of range for many homeowners. Fortunately, there are several lower-cost options for reducing energy loss through windows that utility program managers might consider adding to their incentive offerings.
Reflecting on film
Window films help block against solar heat gain and protect against glare and ultraviolet exposure. According to the International Window Film Association, professionally installed window film can block 30-60 percent of all energy being lost through window glass throughout the heating and cooling seasons. IWFA also claims that window film in commercial buildings can deliver seven times the energy saving benefits per dollar spent compared with installing replacement windows.
DOE’s Energy Saver blog explains that reflective films work best in climates with long cooling seasons, because they also block the sun’s heat in the winter. Other factors that impact the effectiveness of window films include:
- Size of window glazing area
- Window orientation
- Building orientation
- Whether the window has interior insulation
Incentives for professional installation of window films could be a winner for utilities serving low-income areas in warmer climates. Homeowners and businesses in such regions might welcome an affordable alternative to window replacement. Check with your state energy office to see if it offers any tax incentives you can piggy-back on your program.
Drawing on curtains, shades
Carefully chosen window attachments can also save homeowners energy for less than the cost of window replacements. The Attachments Energy Rating Council is a good place to begin exploring options. The two-year-old organization is working with DOE to provide credible and accurate information about the energy performance of residential and commercial window attachment products.
For an overview of AERC’s work, download “Window Attachments: A Call to Action,” the Council’s updated brief. AERC is holding its annual meeting in Annapolis, Maryland, May 22 to 24.
Efficient Window Coverings, a guide supported by DOE and Lawrence Berkeley National Laboratory, is another valuable resource for evaluating different window products for energy efficiency. Website visitors will find a calculator to help them choose the best covering for their circumstances and a comparison chart to see how coverings stack up against each other. These functions can help utilities identify a range of options to appeal to different customer segments.