How to Air Seal Your Home (and How Much You Could Save)

Man caulking around window
Man caulking around window

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Save big on your heating and cooling costs by finding and eliminating the air leaks in your home. Here's how to air seal your home for maximum efficiency and comfort.

Start With a Home Energy Audit

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 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).

Exterior Air Sealing

Check any spot where two building materials meet for gaps or cracks that might let air in or out of your home. This includes, but is not limited to, where the siding and chimney meets, where the siding and foundation meets and where the siding and roof meet. Also 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, while you're at it. Address any issues that you find with exterior-grade caulk or flashing.

Wall Air Sealing

Install foam gaskets behind all electrical outlets and light switches to minimize air flow between the indoors and outdoors. Then, consider installing child-proof plug covers in all your unused outlet 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, too. 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.

Basement/Crawlspace Air Sealing

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. Then, caulk or foam around them. Leaky duct work is a big air escape route, so check all the duct work that you can see and easily access. Use foil tape or mastic to seal any leaks that you find.

Attic Air Sealing

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 certainly 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, etc. You can usually tackle these types of fixes with a can of foam spray. 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.

How Much Does Air Sealing Your Home Save?

According to the EPA, air sealing your home will cut 15 percent off your heating and cooling costs, on average.