Seal air leaks to reduce heat loss

Stop heating the great outdoors

If your home is like most, air leakage is the greatest source of heat loss as heated air escapes from tiny gaps and cracks around your home. You could be spending as much as 40 per cent of your heating bill on warming cold air that sneaks inside.

Save up to 15% on your energy bill

Air sealing has the fastest payback and protects wood framing and insulation from moisture damage. Of all the energy-saving jobs, caulking and weather-stripping are perfect candidates for do-it-yourself projects. A thorough and effective air sealing job can save up to 15 per cent on your heating bill.

Air leakage in a typical home

heat loss in your home

How to stop air leaks

Step 1 Find air leaks on a cold or windy day.

Step 2 Seal up the air leaks.

  • Add weather-stripping, caulking, or shrink-wrap plastic to windows.

Weather-strip doors and windows


Weather-stripping is used on moveable openings, such as doors, windows, and attic hatches. When installed properly, weather-stripping makes openings airtight and can improve energy efficiency by 10 to 15 per cent. It’s inexpensive and easy to install.

  • Buying tips: Check the size of doors and windows, opening direction and colour.
  • Adhesive-backed foam and tape comes in a variety of thicknesses. Just press it into place. Replace every one to two years because it loses its effectiveness over time.
  • Felt weather-stripping is stapled or tacked into place. Fit snugly into door or window jambs of the closed doors or windows.
  • Add a metal door sweep to prevent air leaking out from under the door.
  • The most expensive type of weather-stripping is inter-locking metal used mostly around the edge of doors. It’s more durable and very effective but usually requires professional installation. 

Seal up cracks and gaps

You can easily seal up the gaps and cracks with a can of spray foam insulation and a few tubes of caulking.

window caulking
  • Caulking is a putty-like substance applied to non-moveable gaps such as baseboards and wood trim.
  • Expandable spray foam comes in a can and you use it to seal irregular-shaped gaps or pipes entering your home. Be sure to follow safety regulations on the can.
  • Install shrink-wrap plastic to the interior of windows to create additional layers of glazing.


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