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Locating Air Leaks in Your Windows and Doors

Man caulking a window
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It’s a common problem—that draft you feel coming in through your window or door. Obviously, if you feel the air coming in, then you have air going out as well. If your windows or doors are old, yes you may need new ones. But first, check for air leaks, as there may be an easy solution to the problem. The most significant air leaks tend to occur around windows and doors, so it’s important to seal these problem areas, and the Department of Energy (DOE) offers some great tips for finding these leaks, and then correcting the problem.

1. Perform a visual inspection

Inside your home, inspect around the door and window frames, and the weatherstripping around doors for any cracks and gaps that could cause air leaks. Check the exterior caulking around doors and windows, and see whether or not exterior storm doors and primary doors seal tightly. Inspect the windows and doors themselves for air leaks as well. “See if you can rattle them, since movement means possible air leaks. If you can see daylight around a door or window frame, then the door or window leaks,” according to the DOE website. “You can usually seal these leaks by caulking or weatherstripping. Check the storm windows to see if they fit and are not broken.”

Caulk provides an effective, flexible seal for cracks, gaps and joints that are no more than a quarter inch wide, according to the Efficient Windows Collaborative (EWC). There is a range of caulking compounds varying in strength and price, and these can be purchased at any local hardware store.

Old caulk or paint residue should be removed before new caulk is applied to all joints in the window frame and the joint between the frame and the wall. Relatively warm temperatures (above 45°F) are necessary for the caulk to set properly and adhere to the surface. Low humidity is also important during application to prevent cracks from swelling with moisture, according to the EWC, which also provides advice on weatherstripping.

Weatherstripping helps prevent air leaks around windows sashes. It should be applied to clean, dry surfaces at temperatures above 20°F. Ideally, weatherstripping compresses when the sash is shut. To seal an irregularly-shaped space, more than one type of weatherstripping may have to be combined with others.

After years of use, any kind of weatherstripping should be inspected in case it warrants replacement. Organic felts age fairly quickly, and all felts absorb moisture, reducing their effectiveness. Brush or wiper type weatherstripping eventually gets matted down like a carpet that has had too much traffic. Metal strips are easily dented or bent, and plastics and rubber can become brittle or sticky. Nevertheless, some recent synthetic weatherstripping can be expected to last longer than some other options on the market.

2. Consider hiring a home energy auditor

After performing the visual inspection you may already know where some air leakage occurs. But you’ll need to find the less obvious gaps to properly air seal your home, and an energy auditor can help with that. A Home Energy Professional (HEP) energy auditor can perform a blower door test during an audit of your home. For a thorough and accurate measurement of air leakage, hire a qualified technician to conduct an energy audit, particularly a blower door test. This depressurizes a home and can reveal the location of many leaks. A complete energy assessment will also help determine areas in your home that need more insulation. Use the locator tool to help you find an energy auditor. Some utility companies perform energy audits at low or no cost so definitely contact your utility to see if this is an option. The federal government, as well as state, local, and utility programs, may offer financing help or weatherization assistance, according to the EWC so that may be an option as well.

3. Conduct a building pressurization test

If you don’t want to hire a home energy auditor, the DOE says you may want to conduct a basic building pressurization test to increase infiltration through cracks and leaks, making them easier to detect. They give the following steps on how to do this:

  1. Turn off all combustion appliances such as gas burning furnaces and water heaters on a cool, very windy day. If you don’t want to turn off your furnace, you can just turn on all your exhaust fans to depressurize your home.
  2. Shut all windows, exterior doors and fireplace flues.
  3. Turn on all exhaust fans that blow air outside, such as your clothes dryer, bathroom fans, or stove vents, or use a large window fan to suck the air out of the rooms.
  4. Light an incense stick and pass it around the edges of common leak sites. Wherever the smoke wavers or is sucked out of or blown into the room, there’s a draft. You can also use a damp hand to locate leaks; any drafts will feel cool to your hand.

4. Additional ways to check for leaks

Other air-leak detection methods include the following, according to the DOE:

  • Shine a flashlight at night over all potential gaps while a partner observes the house from outside. Large cracks will show up as rays of light. This is not a good way to detect small cracks, however.
  • Shut a door or window on a dollar bill. If you can pull the dollar bill out without it dragging, you’re losing energy.

5. Consider purchasing new windows and doors

You may also wish to consider replacing your old windows and doors with newer, high-performance ones. Choosing Energy Star windows is a great way to make sure you are purchasing an efficient product so be sure to look for the Energy Star label. If you want a higher level of efficiency, you may want to consider a window company who offers windows with the “Most Efficient” Energy Star designation. Do your homework and research companies before you buy.

Please note, this article may contain links to Amazon products. As an Amazon Associate, earns from qualifying purchases.



Tara Taffera

Tara Taffera was the editorial director for USGlass magazine, AGRR Magazine , and Window Film Magazine. Her skills and more than 20 years of experience have helped her earn numerous journalism awards, including coveted Jesse Neal Awards. Tara enjoys spending time with her family and staying active with her husband by competing in races together, including triathlons. She also spends time volunteering in her community and with her church. Find out more about Tara on Linkedin.

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2 Responses

  1. I need someone to come out to check to see if my glass door is leaking air or it’s getting wet inside I want to know what is it from is it from the Sun that we had I need someone to come out and check it out for me my name is Donna my number is 954-XXX-XXXX

    1. Hi Donna,

      Thanks for reaching out! We have contacted you via email and look forward to locating a company to help find your door’s air leak!

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