5 Spots in Your Home That Might Be Letting in Cold Air

Your home may be dropping clues that its envelope—where interior meets exterior—is letting cold air in or warm air out. Here's how to spot and fix the problems as winter sets in.

A chilling fact: All the leaks, holes, and gaps found around atypical homes add up to the equivalent of leaving a window open every day of the year. "You want to seal off the leaks where you're losing your hard-gained warm air to prevent your dollars from going out through the cracks," says Paul Schollmeier, a home inspector, Home Energy Score Certified Assessor, and owner of Efficiency Detectives LLC. Fortunately, there's a lot you can do yourself.

snow in home illustration
Illustration by Penny Dullaghan

1. Exterior Doors

If you can see light or are able to slide a dollar bill around your door, it's leaking air. Inspect the seals and sweeps at the bottom; if they're worn, replace them with ones that have pliable sealing gaskets that fit snugly against the threshold. Add weather stripping and foam gaskets around doorjambs.

2. Windows

Use incense as a low-tech leak finder. On a cold, windy day, turn off your heater, turn on any exhaust fans, and hold a lit stick near a window. If the smoke gets pulled outside or blown into the room, you've located a leak that needs caulking or weather stripping. Then consider the windows themselves: If you have older single-pane windows, you can insulate them by installing inexpensive low-E glass storm windows. These can reduce heat loss through glass by up to 30%. Plastic film insulator kits are an even more budget-friendly seasonal solution. (A hairdryer is likely required to install.)

3. Attics

Check to see whether your attic access panel or door is insulated. "If it's uninsulated, it's basically like an open door," Schollmeier says. Cut 2-inch-thick rigid foam insulation into three or four panels sized slightly smaller than the door or cover. Glue them onto the covering in layers, then seal around the lip of the opening with rubber weather stripping ($7, The Home Depot).

Homeowners can expect to save an average of 15% on heating and cooling bills by sealing their home properly.

4. Basements

Rim joists—the band of wood that rests on a basement's foundation walls—are often left uninsulated. Cut rigid foam insulation to fit against the joist, filling any gaps wider than 1/4 inch with expanding foam. Seal the edges with acrylic caulk ($4, The Home Depot).

5. Small Stuff

Add store-bought foam gaskets ($2, The Home Depot) behind the outlet and switch plate covers on exterior walls. Look around for the places where utilities enter your house. Fill gaps around plumbing or wires with caulk or insulating foam ($14, Walmart).

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