More than one way to improve window efficiency

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.

Window coverings can offer surprising energy benefits at a lower cost than window replacements, making them a good candidate for utility rebate programs.

Window coverings can offer surprising energy benefits at a lower cost than window replacements, making them a good candidate for utility rebate programs. (Photo by DOE Office of Energy Efficiency and Renewable Energy)

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, You are leaving WAPA.gov. 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 You are leaving WAPA.gov. 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 You are leaving WAPA.gov. 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, You are leaving WAPA.gov. 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.

New program to develop energy-efficiency ratings for window coverings

Fact sheet, website present initial data

(Artwork by Attachments Energy Rating Council)

The Department of Energy (DOE) and the Window Covering Manufacturers Association You are leaving WAPA.gov.  are launching a program to help consumers make informed decisions about products with significant energy-saving potential: window coverings.

The nonprofit Attachments Energy Rating Council You are leaving WAPA.gov. (AERC) is leading the effort to develop an energy certification and rating program for storm windows, awnings, drapes, shutters, shades, blinds and screens.

AERC has been compiling data for the past 18 months and recently unveiled a website where visitors can learn more about its mission, find resources for evaluating building efficiency and read reports from partnering organizations. One report, Window Attachments: Call to Action, targets utilities. It outlines the energy-saving benefits of window attachments, the market size for the product category and the potential effects of an energy certification program.

Why window coverings?
Properly chosen and installed, window attachments can upgrade the performance of existing windows and save up to 13 percent of a household’s annual energy use. Energy savings are not the only benefits window coverings offer homeowners. Far from being purely decorative, window attachments:

  • Enhance daylighting
  • Reduce draftiness
  • Minimize glare
  • Increase thermal comfort
  • Provide privacy
  • Muffle outdoor noise
This thermal image shows how windows are a major source of heat loss on buildings.

This thermal image shows how windows are a major source of heat loss on buildings. (Photo by Attachments Energy Rating Council)

According to the DOE, 80 percent of all households have window coverings, while complete window replacement—a more expensive option—occurs in 2 percent of U.S. homes annually. This creates an opportunity to save consumers energy and money by making the attachments more energy efficient. The AERC rating will help consumers identify products that save energy and increase comfort, and open a space for new utility programs.

Another advantage of window coverings is that homeowners would not have to change their behavior to get the benefits from window coverings. As utility program managers know, it can be difficult to maintain energy savings from measures that require customers to learn new behaviors. However, a study by Lawrence Berkeley National Laboratory found that people already use window coverings in a way that optimizes energy efficiency. For example, people in southern climates tend to keep their window coverings closed in the summer. In terms of persistence, once homeowners invest in storm windows, they generally keep them installed and in good condition.

Ratings rollout
AERC has begun to rate, certify and label attachment products, starting with interior and exterior storm windows, cellular and pleated shades, blinds, solar screens and interior and exterior roller shades. Look for the first AERC-certified window coverings in retail stores by June or July, with additional product categories appearing in late 2017 and early 2018.

If you think efficient window coverings might provide the basis for a new customer efficiency program, bookmark the AERC website so you can follow the publication of the ratings. In the meantime, learn more about window coverings by downloading the fact sheet from Energy Services Publications and visiting Window Coverings and AttachmentsYou are leaving WAPA.gov. an online guide to choosing the right treatment for each window.

Source: Attachment Energy Rating Council, 1/31/17