An average home loses up to 30% of its heating and cooling energy through air leaks. The most significant air leaks tend to occur around windows and doors. To stop air leaks and prevent your home heating and cooling dollars from vanishing in the wind, it’s important to seal any air leaks around windows and doors.

Check for Air Leaks

With windows and doors closed, hold a lit stick of incense near window and door frames where drafts might sneak in. Watch for smoke movement. Note what sources need caulk, sealant, and weather-stripping.

Seal Air Leaks Around Windows

If you have old windows, caulking and adding new weatherstripping goes a long way toward tightening them up.

• Bronze weatherstripping (Around $10 to $12 for 17 feet) lasts for decades but is time-consuming to install.
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• Self-stick plastic types are easy to put on but don’t last very long.
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• Adhesive-backed EPDM rubber (About $8 for 10 feet) is a good compromise, rated to last at least 10 years.
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Nifty gadgets called pulley seals (About $9-$10 a pair) block air from streaming though the holes where cords disappear into the frames.

Seal Air Leaks Around Doors

Check for air leaks, and replace old door weatherstripping with new.

• Foam-type tape has an adhesive backing; it’s inexpensive and easy to install. If it comes loose, reinforce it with staples.
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• Felt is either adhesive-backed or comes with flexible metal reinforcement. It must be tacked or glued into place. It’s cheap and easy to install, but it has low durability.
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• Tubular rubber, vinyl, and silicone weatherstripping is relatively expensive and tricky to install, but it provides an excellent seal. Some types come with a flange designed to fit into pre-cut grooves in the jambs of newer doors; check your existing weather stripping and replace with a similar style.

Check exterior trim for any gaps between the trim and your door frames, and the trim and your siding. Caulk gaps with an exterior latex caulk (About $5 for a 10-ounce tube).

Seal Door Bottoms

If a draft comes in at the bottom, check the condition of the threshold gasket. Replace worn gaskets. If you can see daylight under the door, you may need to install a new threshold with a taller gasket (Around $25 for a 36-inch door). Or, install a weather-resistant door sweep designed for exterior doors (About $9). Door sweeps attach directly to the door and are easy to install.