Air Sealing
The invisible energy thief

Air leakage represents from 5% to 40% of heating and cooling costs. Air sealing increases comfort, makes insulation more effective, and keeps pests out.

What causes air leakage

Air will leak through holes in a home's exterior surfaces whenever there is a pressure difference between interior and exterior. This pressure difference can be caused by:

  • Wind - Wind pressure causes air to leak into homes on their windward side and leak out of homes on their leeward side. Wind leakage may be a major problem area for buildings that are located on hills or on the edge of open fields. This issue can be reduced by sealing leaks on windward building surfaces.

  • Combustion Equipment Ventilation - Bath fans, range hoods, clothes dryers and some combustion equipment take indoor air and exhaust it outside. When this happens, outside air gets pulled in to replace the air being exhausted. Since this replacement air is necessary for these devices to work properly, the goal of air sealing is not to seal every hole.

  • The Stack Effect - A chimney stack will draft when there is a temperature difference between inside and outside the stack. A house behaves much like a chimney only it's a bigger box. In the winter, the inside air is warmer than outside air which makes it more buoyant. This causes it to forcefully rise and leak out holes and seams in the ceiling. Simultaneously, cold outside air leaks in elsewhere to replace the warm air leaving (or vice versa in summer).

Fixing air leakage

Unless your home has wind issues, our focus is stopping the stack effect. This will reduce unwanted air leakage and solve comfort, moisture and combustion safety issues while leaving enough air leakage elsewhere to provide makeup air for mechanical ventilation.

We provide the following air sealing services:

  • Blower door test
  • Infrared scanning
  • Flash & dam chimneys/flues
  • Install recessed light covers and LED inserts
  • Seal wire/plumbing attic penetrations
  • Seal top plates
  • Seal/pack balloon walls
  • Cover/pack soffits & chases
  • Block & seal kneewall floor junctures
  • Target seal rim joist penetrations
  • Cover & seal dirt floors
  • Weatherstrip doors
  • Misc caulking & sealing
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