Air barriers must work together to provide a continuous and complete enclosure of the building envelope—floors, walls and roof. Every subcontractor and installer on the job should understand the importance of maintaining the air barrier. A few holes carelessly drilled in the wrong places can undo the work of many other people.

Passive House air-sealing standards. There are now two Passive House standards – one that originated in Germany, and the other a U.S. offshoot set by the Passive House Institute U.S. (PHIUS) Both have rigorous air-sealing requirements, but the climate-specific PHIUS standard is probably a little more forgiving.

Pretty good air sealing. If you’re not going that distance, consider shooting for a blower-door result of between 1 and 2 air changes per hour at 50 pascals of pressure (ach50). Under the 2012 International Energy Conservation Code, blower-door testing is mandatory:

  • in Climate Zones 3 to 8, houses must test at 3 ach50 or lower

  • in Climate Zones 1 and 2, houses must test at 5 ach50 or lower

See also the EERE Air Leakage Guide.

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