Stop Air Leaks From Inflating Your Heating Bill

Air leaks are one of the biggest sources of wasted energy within the typical home; in fact, it's estimated that the average family spends a full third of their heating and cooling budget on air that leaks into or out of their house! In other words, every time you feel a cold draft by a window, picture money blowing out of your wallet! Luckily, sealing up some of the major sources of unwanted air is surprising easy and affordable. Keep reading to learn about 8 of the most common air leak culprits and how to plug them for good!

Recessed Lights

If they aren't properly insulated, recessed light fixtures are essentially vents that let air flow directly into or out of your attic. To check whether a fixture has built-in insulation, look for a label next to the bulb that says "ICAT", short for "insulation contact and air tight." If your recessed fixtures aren't insulated, seal them by inserting an airtight baffle ($8 to $30) into the light housing or replace them with new, insulated models.

Open Stud Cavities

In the past, builders would often skip sealing walls that weren't visible from the interior living space, such as above a dropped ceiling or behind a ceiling that slopes into the top floor. To check if your home has these open stud cavities, go into your attic and look between the wall studs (you may need to move the insulation to do this). Plug these cavities with unfaced fiberglass insulation (less than $1/square foot) stuffed into plastic garbage bags. For larger gaps, use drywall or reflective foil insulation (less than $2/square foot). Remember to replace the original insulation when you are finished!

Flues and Chimneys

Gaps between the chimney and studs are actually required by building codes to prevent fires, but they have the unfortunate effect of creating air leaks into your living space. HouseLogic recommends using aluminum flashing (about $12) cut to fit the gap and then sealed into place with high-temperature silicone caulk ($14). You can ensure that insulation does not come into contact with the hot flue pipe by placing a cylindrical barrier of flashing around it and leaving a 1-inch space in between the pipe and flashing. Cut and bend tabs inward along the top and bottom of the cylinder to create the spacing.

Attic Access Door

Seal the gap around your attic access door by placing caulking between the frame and rough opening or weatherstripping around the perimeter. Alternatively, buy a pre-insulated hatch cover kit for stairs ($150) or doors ($350 and up).

Medium Gaps

Now that you've sealed the major sources of lost air in the attic, go through and fill in all the minor holes from wires, pipes, etc. Low-expansion polyurethane foam (about $5/can) works very well for this application, but work fast before the can's applicator seals itself shut!

Small Gaps

For openings less than 1/4 wide, caulking is the way to go. Silicone costs the most ($8 a tube) and works better next to nonporous materials, such as metal flashing, but acrylic latex caulk ($2 a tube) is cheaper and will generally get the job done.


Use the same materials (foam for larger gaps and caulk for smaller gaps) to go through and seal your basement. Only openings above the outside soil level will let in air, so focus on those higher areas. Pay special attention to the gap where the house's framing sits on the foundation, as this is a common source of unwanted airflow.

Windows and Doors

As you might imagine, areas where the interior of the house is designed to open to the outside are some of the most common sources of air leakage. Caulking and weatherstripping can be used along both windows and doors with excellent results.


Once you've sealed the air leaks you can easily feel when the weather is cold your home will be more comfortable and less expensive to keep that way.