Windows are an important part of the energy efficiency and comfort of your home. But replacing older, inefficient windows is costly, and it could take 20 years of energy savings to recover your investment.
Luckily, you can make significant improvements to your existing windows without investing a large amount of money or time. Let’s take a look at how we can address heat loss during the winter and heat gain during the summer. We’ll start with the window itself.
Energy loss and drafts often occur in the gaps between the components of the window.
Weatherstripping can be used for areas where a window’s movable parts meet the window frame. Retailers offer various weatherstripping for different types of windows. These materials are low-cost, easy to apply and can pay for themselves in energy savings in as little as one year. Ask your local retailer for guidance.
The seam between the window frame and the wall is another common source of air leakage. For any seam smaller than ¼ inch wide, fill it with caulk; for larger seams, use expanding foam and paint over it. Be sure to follow the manufacturer’s instructions.
If the window pane is loose, or the glass is cracked or missing, it’s probably costing you. If you’re handy, it’s possible to reglaze a window yourself, or there may be a shop in your area that can do it.
Installing low-emissivity storm windows sometimes can produce as much savings as a full replacement. It’s possible to order these windows to the exact size of your window opening. Using low-e glass, which reduces heat transmission, can cut heating and cooling costs by 10%–30%.
Another strategy to consider is window coverings.
There are many types, including interior roller shades, cellular shades and draperies. Recent tests showed that cellular shades can cut heating expenses by up to 24%. Cellular shades can be purchased with a lighter reflective side and a darker, heat-absorbing side. Some can even be reversed with the change of seasons.
Draperies usually are less efficient but can provide a level of comfort during winter and summer months. For maximum effect, make sure they overlap in the middle, are as tight to the window and wall as possible, and run all the way to the floor.
The key to reducing overheating in the summer is to keep the sun’s rays from reaching the window by installing awnings or overhangs above windows that receive a lot of direct sunlight. Window films that adhere to the window surface can reflect unwanted summer sun. Solar screens designed to block the sun also can be effective.
If you’re on a tight budget or there are windows in vacant rooms that you don’t use, you can fasten plywood onto the frame on the outside of the house and cover the inside with rigid foam insulation.
Another low-cost measure for these areas that can produce as much savings as storm windows is to fashion a plastic weather barrier that adheres to the frame. Building supply retailers sell a clear plastic and framing material that can be shrunk into place with a hair dryer.
To learn more about improving the efficiency of older windows, visit energystar.gov or energy.gov.
