Air Sealing

The Passivhaus and Passivhaus Low Energy standards test the seal of a building using a blower door test during construction. They require an air change rate of less than 0.6 and 1.0 ac/h respectively at 50Pa.

By comparison, a CSIRO report (The Evaluation of the 5-Star Energy Efficiency Standard for Residential Buildings, December 2013), published air-tightness results for 20 houses in Melbourne; with an average result a massive 19.7 ac/h@50pa (that’s a “natural” building infiltration/leakage rate of 1 air change per hour 24/7, all year round).

A building with a high NatHERS rating will still consume a large amount of energy if conditioned air is constantly being lost to the outside.