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Stopping Air Leaks


Tighten Up Your House – Stop Air Leaks

Drafts can be uncomfortable – and expensive. Air leaks increase your energy bill by letting heat escape from your home during the winter. The good news is that this is something you can fix yourself with simple tools and the right caulking and weatherstripping.


Where to find leaks

Most commonly, air escapes through:

  • Spaces around your doors and windows
  • Where cables such as phone, television, and other wiring goes through your walls 
  • Around electrical outlets 
  • Around the sill plate where your first floor walls meet the basement foundation 
  • Gaps in an unfinished basement

How to plug leaks and save energy

The best days to tackle this kind of project are when it’s cold and windy outside. Then you can easily feel the drafts. Here are steps you can take to reduce air leaks in your house: 


Around window and door trims

  1. Carefully remove trims
  2. Fill gaps with foam backer rod or low-expansion polyurethane foam. Or caulk along both edges of the trim

Along baseboards

  1. Carefully remove baseboards
  2. Caulk between your wall and the floor

Around electrical outlets on outside walls 

  1. Turn off the power to the outlet 
  2. Remove the outlet cover. Install a CSA-approved foam-insulating pad. Be sure to add a continuous line of caulking along the back of the pad to make it airtight
  3. Replace the outlet cover
  4. Turn the power back on 
  5. Insert a child-safety plug when not using the outlet

In your unfinished basement

  1. Caulk the space between your basement sill plate and the top of the foundation wall with a butyl (rubber-based) caulking (which will adhere to both concrete and wood)
  2. Caulk all cracks and add R20 insulation to the header space above the sill plate. Be sure to add a sealed air vapour retarder on the warm side of the insulation with either six-mil polyethylene and acoustical caulk or a piece of extruded polystyrene caulked in place
  3. Seal all forced-air duct work seams with aluminum tape to ensure conditioned air gets to its destination
  4. If your ducts pass through an unheated space, insulate them with preformed wraps or duct-taped insulation batts
  5. Insulate your basement to reduce heat loss

In your attic 

Even if your attic is insulated, warm air can escape through cracks around plumbing, electrical fixtures, your attic hatch, partition walls (if your home was built before 1970), and ducts and wiring. To stop this:

  1. Weatherstrip your attic door
  2. Caulk the trim, insulate the surface
  3. Close the door tightly with a latch

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