Weatherstripping: Is Your Home Properly Sealed?

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As the cold weather of winter approaches, you’re likely to notice more drafts in your home. Drafts are caused by air leaks in your house’s insulation and sealing, which not only waste energy, they also leak away your money in the form of higher heating costs. Even taking small steps toward filling leaks and gaps in your home can go a long way to save money and keep you snug and comfortable on those cold winter nights.

You can have a professional assess your home for leaks, then fill them, but that is a lengthy and expensive process. Though you are unlikely to be quite as thorough as an expert, a basic job is within the abilities of most DIYers.

What You Will Need

  • A thermal leak detector is an effective way to look for air leaks. Just wave the detector over areas likely to harbor leaks, and look for temperature changes.
  • Weatherstripping for doors and windows.
  • Foam sealant will take care of larger cracks and gaps.
  • Acrylic caulk makes it easy to fill in small cracks or gaps around non-movable parts of your home (not doors and windows).

Where to Check for Air Leaks

Spots that are likeliest to have energy-wasting air leaks in your home include:

  • Exterior corners
  • Exterior water spigots coming through the wall
  • Where the chimney joins the roof
  • Where the foundation and the siding meet
  • Electrical outlets and switch plates
  • Recessed lights
  • Door and window frames
  • Where the dryer vent comes through the wall
  • Window-mounted air conditioners
  • Fireplace damper
  • Attic hatches
  • Vents
  • Corners and windows in the basement
  • Attic corners
  • Anywhere pipes or wires enter the home
  • Mail slots


Looking for Air Leaks

  • Start by visually inspecting all areas of your home that are likeliest to leak. Look for cracks, gaps, or light shining around windows or doors.
  • Check your attic. This is one of the most common areas for leaks. Often there is insulation blocking your view of the walls, which you will need to push aside for a thorough inspection. However, if you have ANY uncertainty about the possibility of asbestos in your insulation, don’t touch it.
  • Close your doors and windows on a piece of paper, and see if you can pull the paper free without it tearing. If so, that door or window can leak air.
  • Doors and windows that can rattle or shake while closed can also leak air.
  • Use your thermal leak detector to check for drafts in all likely places.
  • If you don’t have a thermal leak detector, you can detect some leaks with a stick of incense. Turn off any fans or air conditioning, then light the stick, and hold it near closed windows, doors, corners and areas where pipes enter the home. If the smoke blows to the side, there is a draft there.

How To Fill in Air Leaks & Gaps Around The House

As you discover leaks or gaps, fill them in. Use foam sealant in large cracks, and around electrical outlets, pipes, outdoor faucets, attic registers and the border between wood framing and the foundation in unfinished basements. Use caulk in thin cracks, recessed lights and switch plates. Use weatherstripping around moveable surfaces like doors and windows.

When working with foam sealant or caulk, open windows to provide ventilation.

  • Wear gloves to protect your skin.
  • Keep children and pets away from your work area.
  • Avoid flames and high heat sources while you work.
  • Clean away any dust, cobwebs or other grime from the area to be filled. Use a damp paper towel or rag, then wipe the area dry before spraying foam or working with caulk.
  • Use the straw that comes with most cans of foam sealant to get the material right into the gap you are filling. Caulk usually comes in a tube with a very narrow tip for precise application.
  • Spray foam slowly and carefully to avoid overfilling the space. Generally, foam will double its size with expansion, so fill each space about halfway, then wait to see if you need to add more.
  • Once the foam has hardened, usually within five minutes to an hour, you can use a utility knife to trim away any excess material.
  • Apply caulk in a narrow ribbon into and around cracks and areas that need sealing. If you need to press the caulk flat to fill a space, use a damp, gloved finger.
  • Clean up any caulk spills or overfills with a damp rag.

Filling in air leaks can save you several hundred dollars each year in energy costs. It’s not a difficult project, and can be tackled over a weekend. When you see your lowered heating bills during the coldest winter months, you’ll be glad you took the time.

Last Updated: November 14, 2012
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About Michelle Ullman Michelle Ullman has lived and gardened in Southern California since childhood. A freelance writer, she covers topics ranging from gardening to home improvement to health issues. She also has experience as a catalog copywriter and poet. Michelle has trained and worked as a respiratory therapist and surgical technologist, but prefers to spend her time gardening, and walking with her dog. Michelle holds a Bachelor's Degree from Redlands University in Business Management. 

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