In addition to the tips below, visit myEnergy Marketplace for additional information on what to look for in energy-efficient products, as well as cost-saving rebates.

Window insulation tips

Five easy ways to seal in the heat and stay comfortable all year round

photo of the windows on the top floor of a cottage in winter

Windows are one of the most common areas for heat to escape, but proper use of weatherstripping and caulking is often enough to lower your electricity use. Want to identify the air leaks? Try lighting a candle or stick of incense and moving it slowly around the window frame. If it flickers, you’ve got a draft. Spiderwebs are another telltale sign because spiders like air circulation. Once you’ve identified the leaks, head to the hardware store for some do-it-yourself kits, and try one of these five easy ways to seal a drafty window.

icon of a drafty window

1. Get a draft stopper

A draft stopper is typically a tube made of fabric and filled with sand that you place on your window sill, and it’s one of the easiest ways to prevent heat loss. You can buy a fabric and foam kit, or sew and stuff your own draft stopper.

icon of window drapes

2. Draw the drapes

Enhance the insulating effect of drapes or curtains by adding thermal insulated ones, which have extra layers of fabric or acrylic foam. For better heat retention, look for heavier fabrics, make sure they cover from floor to ceiling, and consider adding a “pelmet” — a cover above the curtain rod — to trap cold air.

icon of weather-stripping

3. Install weatherstripping

Weatherstripping is any product that seals air leaks at joints where two surfaces meet and move, and it’s ideal for the budding do-it-yourselfer. All you need is a utility knife, tape measure and cleaning tools. Apply self-adhesive strips of felt, foam, rubber or V-strips, which fold into a V and double up when closed. More experienced DIYers can try compression weatherstripping, rigid foam or foil tape.

icon of a caulking gun

4. Apply caulk

Caulking is a flexible material for sealing gaps and cracks less than a quarter inch wide, usually between walls and window casings. You’ll need a caulking gun, cartridges of compound, a utility knife, and a wire brush to remove dried caulk. Fill the crack completely, making sure it touches both sides. If the windows rattle, use glazing compound to seal between the window pane and wooden frame.

icon of a drafty window

5. Shrink-wrap windows

Window film is an easy, low-cost solution for windows that stay closed all winter. You’ll need a DIY kit, plus a utility knife and hair dryer. Apply the double-sided tape to the inside of the window frame, attach the film, and use the hair dryer to shrink the film to an air-tight seal. This creates an extra insulating layer by trapping cold air.


Not sure where to start? Remember: warm air rises so, when in doubt, start at the top. If you have a chimney, try closing the flue. If you have an attic, see if it’s insulated. If your home has two or more storeys, try insulating the windows on the top floor first. When you’re ready to invest in new windows, look for the ENERGY STAR® certification. Meanwhile, consider taking a small step to seal in the heat and watch for changes in your home’s energy consumption over the winter.

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