Affordable Strategies for Drafty Windows

Windows are an important contributor to the efficiency and comfort of your home. In last month’s column, we talked about replacing windows, but doing so is costly, and it could take 20 years of energy savings to recover the 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 gain during the summer and heat loss during the winter. We’ll start with the window itself.

Energy loss and drafts often occur in the cracks between the components of the window. Weather stripping can be used for areas where a window’s movable parts meet the window frame. Retailers offer a variety of weather stripping 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 anything less than ¼ inch wide, fill it with caulk; for anything larger, 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 additional money. If you’re handy, it is possible to re-glaze a window yourself, or there may be a local shop in your area that will do it.   

Installing exterior or interior storm windows can sometimes produce as much savings as a full replacement. It’s possible to order these windows to the exact size of your window opening. Recent testing by a national laboratory showed that storm windows could cut heating costs by 7 to 12 percent.

Another strategy to consider is window coverings. There are many types, including interior roller shades, cellular shades or draperies. Recent laboratory tests showed that cellular shades could cut cooling or heating expenses by 10 to 16 percent. 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 are usually less efficient but can also provide a level of comfort during summer and winter 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 summer sun can also be effective.  

If you’re on a tight budget or there are windows in vacant rooms that you don’t really 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 by using a hair dryer.