5 ways to winterize windows and keep your home warm

Iris Price | Improvement Center Columnist | December 18, 2015

wood windowYou welcome winter -- the promise of a silent overnight snowfall; lacy, leafless trees smothered in a white blanket knit from snowflakes; the bracing jolt of crisp, cold air when you venture out.

Or maybe not. Regardless of how you feel about living in a cold climate, you probably shiver when you receive your winter heating bills. Keeping the cold outdoors can be costly, especially if you have a lot of windows. The better the view, the more heat you can lose. According to the Department of Energy's website, Energy.gov, whether you have old windows or newer, replacement windows, they can account for as much as 30 percent of your home's heating loss.

If you want to prevent heat loss from your windows, there are basically two ways:

  1. Prevent drafts of cold air from cracks in or around the windows
  2. Insulate the glass for winter with temporary or permanent coverings

The following methods can winterize your windows one of those two ways to keep your home warm and your heating bills reasonable when the weather turns chilly.

1. Sealing and caulking windows

Air moving in and out of a building through cracks and holes around the windows is commonly referred to as air leaks or drafts. Energy codes for new buildings establish modest air leakage rates for windows at wind speeds of 25 mph. Window manufacturers typically exceed these minimal requirements. Codes, however, also require installers to seal around the exterior joints of window frames and joints between windows and wall cavities.

Proper window installation requires caulking windows around exterior trim and sometimes behind window fins to reduce air leakage through the rough openings. On the interior side, installers may stuff scraps of insulation into the rough openings and seal it with caulking or insert expandable foam caulk, rope caulk or polyethylene backer rod to prevent additional air leakage.

If you feel cold drafts around your windows, you are losing heat there in winter. Even if you don't feel a draft, you may have air leakage around your windows. An energy audit can uncover less obvious air leaks with a blower-door test or infrared thermometer.

Inspect around the frames of each window for cracks and gaps or deteriorating caulking, rotting wood and cracked or missing glass. Repair or replace rotted wood frames and seal or replace cracked or broken glass. Older, single-pane windows may be loose where they are attached to the frame. Look, also, for openings behind the interior window trim or wall finish to insert non-expanding foam in the 1/4" to 1/2" gap between all four sides of the sash and frame.

If the caulking needs replacing, thoroughly dig out the old caulking with a putty knife or screwdriver, clean and dry it before re-caulking with an appropriate compound for caulking windows. Temperature should be above 45° F. and humidity should be low for caulking to cure properly.

While caulking is the right choice to seal joints that remain stationary, use weather stripping on movable window parts.

2. Weather stripping

Weather stripping comes in felt, open-cell foam, different types of metal and vinyl. The application and your level of skill may determine which type you choose. Some may be visible when the windows are closed, so consider its appearance.

Felt is inexpensive and applies easily but less durable than the others and doesn't withstand moisture. It's also less efficient at blocking drafts. Vinyl may not be as easy to install as felt, but it's reasonably priced. Metals look less out of place than the others in older or historic homes. Magnetic strips are expensive but highly effective for sealing air leaks.

If you're not usually a DIYer, you may think, "How hard could this be to install?" Carefully consider the pros and cons of each type, as you may find certain types of weather stripping too difficult to work with.

3. Storm windows

Storm windows used to be the go-to method to winterize windows when all windows were single-pane. They don't provide insulation, but they prevent air movement through single pane windows that are in good condition.

Storm windows range from plastic sheets designed for one season's use to plastic panels to high-quality, low-emissivity glass that reduce heat transmission. They may be designed either for exterior or interior installation, but interior storm windows are easier to install and keep clean.

Some storm windows are meant to be permanently installed; however, if you can afford low-e, glass storm windows, you may want to skip the storms and consider replacement windows.

4. Thermal window fashions

One of the easiest ways to keep the heat inside, heavy thermally lined drapes whether floor length or sill length do work, and they definitely look a lot better than putting plastic over the windows. They can be changed out for a lighter window treatment in spring and summer, and you can always open them when you want to enjoy your view. Hang them as close to the windows as you can and let them stop at the sill or the floor. For even better energy-efficiency, velcro them to the walls and overlap the panels where they meet. You can also double hang regular drapes for the same thermal benefits.

5. Window film

If you are wondering how window film can keep your house warm when you thought it was meant to keep the sun out and your house nice and cold in the summer, you might be missing out on one of the latest advances in year-round indoor temperature control.

According to Charles Bonfiglio, CEO of Tint World, a leading residential and automotive window film installation franchise, "in the winter, glass panes lose a substantial amount of your home's heat and lets the interior heat seep out, but certain window films trap room heat for year -round comfort." The newer window films absorb the radiant heat from the interior of your home, keeping it indoors. Different films are available to accommodate different types of windows and even skylights. Many of these films can be used with low-e windows. Security films that are thicker but use the exact same technology protect you from shattering glass, so if you also live in a storm-prone area, for a few dollars more a square foot, you can get an extra layer of protection for your home and stay warm in winter.

About the Author

Iris Price is a single Baby Boomer whose antidote to a lack of retirement funds was to launch a long-delayed career as a writer. While others her age concoct bucket lists and travel the world, she bought a new-construction home and obsessively creates lists of must-have home improvements and personal realization goals. She specializes in writing about home services and self-motivation.