How Does Air Leak From Your Home?

How Does Air Leak From Your Home?

Most people ignore air leaks until winter comes. It’s the time of the year when the residents feel the effects more than any other month. The most common leaks are those “drafts” in the doors and windows, but they’re not the biggest culprits of wasted energy. That title belongs to the air leaks hidden in the attic and basement.

How To Find Air Leaks In Your Home

The fact that air leaks account for up to 30% of energy costs is enough to convince you to address it. The cracks and gaps inside the doors and windows are the easiest to fix, but when leaks come from hidden locations, that’s when things get more demanding for a DIY solution.

Air leaks force your HVAC equipment to work harder to achieve a comfortable indoor atmosphere. A heating and cooling system that works harder than usual results in higher energy bills.

You need to find where those leaks since they must be sealed immediately. If you keep on ignoring them, you’ll notice a significant increase in your energy bill; not to mention the fact that those leaks make everyone feel uncomfortable staying inside.

You can locate the leaks on your own, but it’s no cakewalk. Most of them are hidden behind walls and under the insulation. In the cold months, warm air rises and goes up to the attic, while cold air from the outside enters the living space through the drafts. The leaks’ existence means that air heated by your heating equipment is wasted, plus it must work harder to counteract the entry of cold air.

Air leaks are typically found in:

  • Attic hatch
  • Plumbing vents
  • Wiring holes
  • Windows
  • Doors
  • Recessed light
  • Soffits
  • Furnace flue
  • Basement rim joists

Basement Leaks

Take a closer look at the top of your basement wall, specifically the area where the cement contacts the wooden frame. This is where air leakage is usually found. The wall’s top is above ground, drawing outside air via the wooden frame’s cracks and gaps. The perimeter framing (rim or band joist) creates multiple cavities along the wall, all of which may open up and produce leaks.


Identifying and Measuring Air Leakage in Your Home

Call a qualified technician for a comprehensive energy audit. Property owners can detect air leaks without an expert, but measuring the leakage is another thing. An expert performs a blower door test, where the living space is depressurized to reveal the leaks. Moreover, the technician conducts an energy assessment of your home to determine which areas could benefit from improved insulation.

Aside from a blower test, you can do a visual inspection in and out of the property. A standard visual inspection must include:


  • Areas where the siding and chimney meet
  • Outdoor water faucets
  • Exterior corners
  • Areas where the bottom of the siding or brick meet with the foundation


  • Switchplates
  • Baseboards
  • Door and window frames
  • Electrical outlets
  • Attic hatch
  • Phone and cable lines
  • Fireplace dampers
  • Gas service entrance
  • Electrical service entrance
  • Window type ACs
  • Fans and vents

Pay attention to those gaps in foundation seals, mail slots on the door, and around pipes and wires. Caulking and weatherstripping will do fine in these areas. Be sure to leave no cracks or gaps. Don’t use used weather stripping as it is most likely in bad condition.

The windows and doors are a copious source of air leaks. If the windows rattle, there’s likely an air leak. If daylight shines through the door and window frame, then air is undoubtedly going to pass in those gaps, too. You’re better off replacing old doors and windows with efficient and high-performance varieties. If you can’t afford a pre-made energy-efficient door or window, the next best thing is to install affordable plastic sheets.

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