Air Sealing - High Performance Building

Infiltration, or air leakage through the exterior building skin, is one of the major energy losses in most buildings.  Therefore, proper air sealing is an essential strategy for a successful high performace building.  As buildings get tighter, however, combustion air from gas appliances and the off-gassing of chemicals from interior finish materials must be exhausted mechanically and fresh make-up must be carefully introduced into the occupied spaces of the building without creating any cold drafts.  Combined with heat recovery ventilation systems, air sealing can improve the comfort of interior environments while not sacrificing indoor air quality.  The proper location and installation of air barriers and thermal insultaion in the building envelope, and detailing around all wall and roof penetrations need careful attention.  Understanding of basic building science is neccessary to properly integrate the air barrier, thermal barrier, and rain screen within the structure of a high performance building.  images by Marc Rosenbaum from his presentation at the NESEA conference in Boston, MA.