Energy Fixer: Window Coverings

How do you make an older house more energy efficient? This year, we’re following Sarah, a PGE employee, as she updates a 55-year-old, 1,500 square-foot, all-electric house, which she purchased in November 2014.

When Sarah moved into her new home, she figured replacing the aluminum windows would be one of the first things she should do to save energy. But after some research, she’s holding off on investing in new windows and buying energy-efficient window coverings instead.

“I had a big ‘a-ha’ moment when my home energy audit showed that other steps, such as adding insulation and sealing air leaks, would probably have a bigger impact on the energy efficiency of my house,” Sarah said. “New windows are a big investment. But double-pane vinyl windows would provide only an incrementally higher R-value than my existing double-pane aluminum windows, so I couldn’t justify spending the money right now.”*

Solution: cellular shades

Sarah needed window coverings to provide privacy, and she opted for energy-efficient cellular or “honeycomb” shades.

The honeycomb design creates little pockets of air that add an insulating value of R-2 to R-5, according to manufacturers. The shades Sarah purchased are rated at R-4.39, while the blackout models in her bedroom are R-4.76. (The higher the R number, the better the performance.)

Sarah is excited that the new shades will cut drafts, improve comfort and help control heating and cooling costs. They will keep warm air inside during winter and block solar heat gain during summer so her ductless heat pump won’t have to work as hard.

“The living room has a large picture window, and the room heated up quickly on sunny days this winter. I realized that it would be awful in summer.” Sarah said. “When the shades were installed, they made a big difference right away.”

Drapes and other options

Drapes — especially styles with thermal linings — are another type of window covering that can help improve comfort and save energy. Styles that reach all the way to the floor and wrap around the edge of the window do the best job of blocking drafts and reducing energy loss.

Some homeowners opt for temporary storm window kits or Portland’s own Indow Windows, which are clear acrylic window inserts, to block drafts and boost energy efficiency.

When does it make sense to replace windows?

Energy efficiency was Sarah’s top consideration when weighing whether to upgrade her windows at this time. If you’re trying to decide, consider the age, materials, construction, condition and appearance of your existing windows.

New, energy-efficient windows can:
  • Cut heat loss in winter to help save on energy bills. According to ENERGY STAR®, replacing single-pane windows with new energy-efficient double-pane models can reduce energy bills up to 15 percent.
  • Block solar heat gain in summer to reduce overheating and help save on cooling.
  • Reduce drafts and air leaks.
  • Improve home comfort year-round.
  • Reduce condensation.
  • Improve home appearance and may increase home value.
  • Help reduce noise from outside.

Keep in mind that windows act as part of your home’s thermal envelope, so new windows are most effective if your house is properly insulated and sealed against air leaks.

Incentives available

While windows are a big investment with a long-term payback, Energy Trust of Oregon cash incentives can help make them more affordable. Also, manufacturers and installers often offer special pricing.

More resources for you

*Savings estimates will vary based on circumstances. Consult an Energy Trust of Oregon trade ally contractor to evaluate your home.