Detecting Air Leaks

You may already know where some air leakage occurs in your home, such as an under-the-door draft, but you’ll need to find the less obvious gaps to properly air seal your home. For a thorough and accurate measurement of air leakage in your home, hire a qualified technician to conduct a blower door test. A blower door test can reveal the locations of many leaks.

Diagnostic Tools

Testing the airtightness of a home using a special fan called a blower door can help to ensure that air sealing work is effective. Often, energy efficiency incentive programs, such as the DOE/EPA Energy Star Program, require a blower doot test (usually performed in less than an hour) to confirm the tightness of the house.


A complete Do-It-Yourself Energy Audit will also help you identify air leaks in your home. You can find air leaks yourself, without a blower door test. First, look at areas where different materials meet, such as between brick and wood siding, between foundation and walls, and between the chimney and siding. Also inspect around the following areas for any cracks and gaps that could cause air leaks:

  • Door and window frames, e.g., if you can pull a piece of paper through a shut door or window without tearing the paper, you’ve got an air leak.
  • Mail chutes
  • Electrical and gas service entrances
  • Cable TV and phone lines
  • Outdoor water faucets
  • Where dryer vents pass through walls
  • Bricks, siding, stucco, and foundation
  • Air conditioners
  • Vents and fans

Source Material: US Dept. of Energy

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