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Find and seal air leaks

Where homes leak air, how to find leaks yourself, and how to fix them cheaply.

Cost: $20 to $150 6 min read

Air leaks let heated or cooled air escape and outside air sneak in. Sealing them is usually one of the most cost-effective energy upgrades, and many of the fixes are DIY-friendly.

Where to look

  • Attic hatch, recessed lights and plumbing or wiring holes into the attic
  • Around windows and doors
  • Outlets and switches on outside walls
  • Where pipes and cables come through walls
  • Basement rim joists and dryer vents
  • Fireplace dampers

Find them

  1. Pick a windy day, or turn on bathroom and kitchen exhaust fans with windows closed.
  2. Hold a lit incense stick near suspected spots; watch for the smoke to waver.
  3. Feel for drafts with a damp hand.
  4. Look for daylight around doors and spider webs moving in a draft.

Fix them

  • Caulk for small gaps that don't move
  • Spray foam for larger gaps around pipes (follow the label)
  • Weatherstripping and door sweeps for doors and operable windows
  • Foam gaskets behind outlet and switch covers on outside walls
  • Insulate and weatherstrip the attic hatch

General energy-saving information. Savings vary by home, climate, equipment and rates. Efficient Home Help isn't paid by any utility, brand or contractor.