9 Ways to Seal Leaks and Reduce Your Winter Heating Bill


You might know all the usual ways to reduce winter heating costs — putting on a sweater, adding more insulation to the attic, closing off unused rooms. But hot air may be leaking from your home in places you haven't considered, and many small cracks can add up to the equivalent of an open door or window.

Besides windows and doors, warm air may be leaking out through electrical outlets, electrical and gas service entrances, attic hatches, wall- or window-mounted air conditioners, cable TV and phone lines, vents and fans, and dryer vents. (See also: 10 Frugal Ways to Keep Your Home Warm This Winter)

Find Those Air Leaks

If you're serious about finding air leaks, you might consider having an energy audit done. The audit might reveal less obvious ways to reduce your heating bill. An energy auditor can use a blower door, a powerful fan mounted into the frame of an exterior door, or an infrared temperature sensor to find air leaks.

Try to have the last 12 months of utility bills on hand to show the auditor, and be wary of contractors primarily interested in selling their products. Before considering paying a contractor, check if your local utility or government offers free energy audits.

You can also use some tricks to find leaks on your own, according to the U.S. Department of Energy (PDF):

  • Hold a lighted candle near windows, doors, and light fixtures. Smoke moving horizontally means there’s a leak.
  • One way to find large air leaks is to shine a flashlight at a door jamb or window sill where you suspect a leak while someone inside the house looks for light coming in.
  • You can also shut a door or window on a piece of paper. If you can pull the paper out without tearing it, you're losing energy.

Another alternative is a building pressurization test. Here's how the Department of Energy describes the process:

  1. Close all exterior doors, windows, and fireplace flues.
  2. Turn off all combustion appliances, including gas burning furnaces and water heaters. Note: If you do not wish to turn off your furnace, you can omit step 2 and go to step 3.
  3. Turn on all exhaust fans that blow air outside, such as bathroom fans or stove vents.
  4. Light a smoke candle or incense stick and pass it around the edges of common leak areas. If smoke is drawn into or out of a room, then there is an air leak.

Plug Those Money Leaks

Once you find your leaks, you can take steps to stop your warm air — and your money — from pouring out. Here are nine ways to close those drafty gaps.

1. Install Door Sweeps

These are available at any hardware store. Add them to all your exterior doors.

2. Install Outlet Gaskets in Electrical Outlets

You won’t need these for all your outlets, just those on your home's outer walls, where warm air often escapes.

3. Add Caulk to Window Frames

Rope caulk might be easier than a caulking gun. Put weather-stripping on movable joints.

4. Limit Use of the Fireplace

Although it seems counterintuitive, fireplaces actually pull heat out, especially since the damper must remain open after the fire is out but coals are still smoldering. Close the damper when the fireplace is not being used.

5. Open Shades and Curtains During the Day

This is especially true for windows on the south-facing sides of your house, so the sun can warm the house. Close them at night to help trap heat inside.

6. Keep Heating Vents Clear

Be careful not to block heating vents with furniture or rugs. Vacuum them once in a while to keep them clean.

7. Cover Your Kitchen Exhaust Fan

If your range hood vents outside, cover it when you're not using it to stop air leaks.

8. Open the Bathroom Door

Leave the door open when you shower to let steam spread to other rooms, and leave the ventilation fan off.

9. Renovate for Big Savings

If you have older single-pane windows or an older furnace, you could get huge savings by installing new energy-efficient windows and a new furnace. Older furnaces and boilers had efficiency ratings anywhere from 56 to 70%, while modern high-efficiency heating systems can have efficiencies between 90 and 98.5%. You can opt to retrofit your old furnace or boiler to cut costs if you can't justify the expense of new one.

What frugal keep warm strategies are you using this winter?

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Guest's picture

closing off unused rooms IS NOT good idea, b/c (per my HVAC man) it causes too much "draw" on the heat/AC system...you or whoever bought this heat/AC system to heat /cool a certain number of cubic feet. when you change the number of cubic feet, it causes the system to work much harder than it's built/bought for

dunno bout you, but i want to replace my system NO SOONER than every 20 years

Guest's picture

Thanks for these tips. It seems our front door has several leaks, at the top and sides, and so I'm torn whether I should get strips to attach or have a whole new door made. Things to ponder! Thanks!

Guest's picture

My Dads house was built in the 1800's, so it has a lot of places that were leaking air. He's a real handy man, but needed some help actually finding the places that were letting air out. Once he had an energy audit done, he knew exactly where to put a little bit of blockage up and really saw a difference in how much heat they had to use during the winter.

Guest's picture

If you can’t insulate your room or block draughts, it will be hard to heat the whole room, especially with a small electric heater. In this case you are better off sitting near the heater, so it at least keeps you warm. If you can’t heat the room, heat yourself .... i think