You may already be aware of some air leakage in your house, such as through a drafty window, but to fully air seal your home, you’ll need to discover the less visible gaps.

Hiring a competent specialist to do an energy assessment, particularly a blower door test, can provide you with a complete and precise evaluation of air leakage in your house. Many leaks may be located with a blower door test, which depressurizes a home. A comprehensive energy evaluation will also assist in determining which portions of your home require more insulation.

There are techniques to discover air leaks without using a blower door test.


Inspect any points where two distinct building materials meet on the outside of your home, including:

  • Every exterior corner
  • Outdoor water faucets
  • Where siding and chimneys come together
  • The junction between the foundation and the bottom of the outside brick or siding.

Inside your home, look for cracks and holes that might lead to air leaks in the following areas:

  • Attic hatches
  • Door and window frames
  • Wall- or window-mounted air conditioners.
  • Vents and fans.
  • Electrical outlets
  • Switch plates
  • Electrical and gas service entrances
  • Baseboards
  • Cable TV and phone lines
  • Where dryer vents pass through walls
  • Weather stripping around doors
  • Fireplace dampers

Look for gaps around pipes and cables, as well as foundation seals and mail openings. Examine the caulking and weather stripping to ensure that they are correctly applied, have no gaps or cracks, and are in good shape. Check the external caulking around doors and windows, as well as the seals on exterior storm doors and main doors.

Examine the windows and doors for air leaks. Check to see if you can shake them, since movement indicates probable air leakage. If you can see daylight around the frame of a door or window, the door or window is leaking. Caulking or weatherstripping may typically be used to fix these leaks. Check the storm windows to ensure they fit and are not damaged.

You could also think about replacing your outdated windows and doors with newer, higher-performance models. If new factory-made doors or windows are too expensive, you can cover the windows with low-cost plastic sheets.

Building Pressurization Test

While not as effective as a blower door test, if you are having problems detecting leaks, you may wish to do a basic building pressurization test to enhance infiltration via cracks and leaks, making them easier to detect:

  • On a chilly, windy day, turn off all combustion appliances, such as gas furnaces and water heaters.
  • Close all windows, external doors, and fireplace flues.
  • Turn on any exhaust fans that blast air outdoors, such as your clothes dryer, bathroom fans, or kitchen vents, or use a large window fan to pull air from the rooms.
  • Light an incense stick and carefully pass it around the perimeters of regular leak locations. A draft exists anywhere the smoke wavers, is drawn out of, or blown into the room. You may also find leaks with a moist hand; any drafts will feel chilly to your fingers.

If you don’t want to switch off your furnace, you may depressurize your home by turning on all of your exhaust fans. Other ways for detecting air leaks include the following:

  • At night, shine a flashlight over all potential holes as a partner monitors the house from the outside. Large cracks will appear as light beams. This is not an effective method for detecting minor fractures.
  • Close a door or window with a dollar note. You’re wasting energy if you can pull the dollar bill out without it dragging.

Need someone to help you detect if there are air leaks in your home? Calvey Heating and Air is here to help. Feel free to reach us if you need professional help.

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