The more air that flows in through little cracks, holes and gaps in your home’s exterior, the more you have to heat—or, in summer, cool. When that conditioned air escapes to the unheated attic or the outside, you’ve wasted energy and money.
Home energy experts say sealing those openings is one of the most cost-effective ways to cut your heating and cooling bills. Best of all, it can decrease drafts and make your home more comfortable.
Following are common sources of air leaks in the home and methods for sealing them. It’s not a complete list, but it covers leaks that are reasonably easy for do-it-yourselfers to handle.
Only you know your capabilities, however. Some jobs may be better left to a pro.
It’s also worth noting that air sealing goes hand in hand with insulation, which stops heat loss but not air flow. That’s a separate topic, but it’s one worth exploring if you want to minimize your energy costs and make your home more comfortable.
We compiled the information with help from David Gordon, Gary Canter and David Schiever of HomeEnergyMD and its parent company, Regency Window Co. in Twinsburg, Ohio; Matt Pickston of Pro Energy Consultants of Sagamore Hills, Ohio; and the government’s Energy Star program.
Windows and doors: Air often enters the home through spaces around window frames, window sashes and exterior doors. Adding weatherstripping and door sweeps allows windows and doors to seal more tightly. Various types of weatherstripping are available, including adhesive foam strips, gaskets and spring-type seals.
Caulking around window and door casings stops air that may enter through gaps that are hidden by the trim. Use paintable caulk, and choose clear caulk for woodwork that’s varnished or painted a color other than white.
Baseboards: Cold air can seep in through gaps between the floor and wall that are covered by baseboards. That’s true even on interior walls, because cold air often travels through wall cavities. A telltale sign of an air leak is dirt on the carpet near the baseboard, deposited there by the moving air.
Run a bead of caulk along the joint between the baseboard and the wall to block the leak. You can also caulk between the baseboard and the floor, if it’s not carpeted.
Electrical outlets and light switches: In both exterior and interior walls, air can leak around the electrical boxes that hold outlets and switches. Hardware stores and home centers sell flexible foam seals designed to stop those leaks. Just remove the cover over the outlet or switch plate, slip on the seal and replace the cover.
Plugging the outlets with baby-proofing plugs will further stanch the air flow.
Fireplace: Fireplace chimneys are notorious sources of air leaks. Closing the damper helps, but it doesn’t seal the opening tightly.
You can create a better seal by installing an inflatable chimney balloon, especially if you use your fireplace infrequently. The balloon has a part that hangs down into the firebox to remind you to remove it before you start a fire.
Exterior walls: Wherever pipes, wires or vents enter or leave your house, air can, too. Seal smaller openings with caulk and larger gaps with a minimally expanding spray foam sealant.
Basement ceiling: Any penetration in your basement ceiling is a place where air can enter wall cavities. Look for pipes, wires and other systems going through the ceiling, and seal the spaces around them with caulk or spray foam. For bigger openings, cover with foam board and seal the board in place with caulk.
Sill plate: The sill plate is the plank at the top of the basement walls where the foundation meets the house framing. In most homes that plate is topped by a band of lumber called a rim joist.
Gaps are common here and can be sealed with caulk or minimally expanding foam. Or you can cut rigid foam insulation to fit over the rim joist cavities and then seal the insulation in place with caulk.
©2011 the Akron Beacon Journal (Akron, Ohio)