How to Air Seal Your Home

Man caulking around window

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Project Overview
  • Working Time: 4 - 5 hrs
  • Total Time: 4 - 5 hrs
  • Skill Level: Beginner

Save big on your heating and cooling costs by finding and eliminating the air leaks in your home. According to the EPA, air sealing your home will cut your heating and cooling costs by an average of 15 percent.

Many utility companies offer free home energy audits. If yours does, schedule an appointment to have your home checked out by a pro. They'll probably do what's known as a blower door test to identify the air leaks in your home. That's when they depressurize your home to see where the air is escaping. It's likely to catch issues that you might otherwise miss. If your utility provider doesn't offer this free service, consider hiring a certified energy auditor to conduct a test for you.

Want to save money by doing your own energy audit? Here's how to spot the air leaks in each area of your home (and how to fix them yourself).

What You'll Need

Equipment / Tools

  • Flashlight
  • Ladder (if needed)


  • Exterior-grade caulk
  • Flashing
  • Interior caulk
  • Foam gaskets for outlets and switches
  • Weatherstripping
  • Child-proof plug covers (optional)
  • Foil tape (or mastic)
  • Foam spray insulation


  1. Seal the Exterior Air Leaks

    Walk around your home and check any spot where two building materials meet. You're looking for gaps or cracks that might let air in or out of your home. This includes, but is not limited to, the area where the siding meets the chimney, the siding meets the foundation, and the siding meets the roof.

    Check any places where plumbing, electrical, or vents come through exterior walls, the foundation, and the roof. And don't forget to check the seals around all of your windows and doors. Address any issues that you find with exterior-grade caulk or flashing.

  2. Seal Up the Walls

    Install foam gaskets behind all electrical outlets and light switches to minimize airflow between the indoors and outdoors. Consider installing child-proof plug covers on all your unused outlets to keep cold air from coming through the plugs. If you have cable and/or a landline in your home, be sure to insulate behind those receptacles, too.

    Once you have that tackled, check your windows, doors, and baseboards for cracks or gaps where air can get through. Address those with caulk or weatherstripping. If you have window or wall-mounted air conditioners, be sure to check around those.


    Do you have windows that are more than 20 years old? Consider replacing them (or adding storm windows) to increase their efficiency. Living in an older home? If you suspect your walls aren't insulated, consult a professional to see what your options are. According to Energy Smart Ohio, uninsulated walls account for 20-40 percent of a home's air leakage.

  3. Seal the Basement or Crawlspace

    Look over the rim joists and sill plates carefully, and seal any cracks between them and the foundation. Also seal any holes that go through a rim joist or the foundation for hose bibs, electrical work, HVAC lines, dryer vents, gas water heater vents, etc. Caulk or foam spray should be sufficient to address these types of issues.

    Check for any holes that go through the main floor/basement ceiling, for ductwork, electrical, plumbing, etc. Caulk or foam around them. Leaky ductwork is a big air escape route, so check all the ductwork that you can see and easily access. Use foil tape or mastic to seal any leaks that you find.

  4. Seal the Attic Space

    There are lots of places in the attic where heated and cooled air can escape your home, so it's important to address each one. While there are things that you can do yourself, this is one area where you may want to bring in a pro. They'll be able to tell you if you're attic is insulated adequately.

    Not ready to spend money for professional advice? Here are some things you can tackle yourself.

    Seal around any holes in the attic floor or roof that have been made to accommodate lights, ceiling and vent fans, plumbing stacks, or attic access. You can usually tackle these types of fixes with a can of foam spray insulation. Chimneys and recessed lights need to be handled differently, so don't insulate those areas with foam.


    While you're poking around your attic, look for dirty spots on the insulation. That's a sign that you have an air leak, and maybe even a water leak.