Passive Houses

A recent air leakage test on one of our Passive House projects achieved 0.24 ACH@50 (air changes per hour at 50 pascals pressure), well under the 0.6 ACH@50 required to achieve Passive House certification! Compared to the typical range of 5.0 to 15.0 ACH@50 for houses constructed under the energy efficiency requirements of NCC2019, this high-performance home is one of the most thermally efficient buildings in Australia.

Pursuit of thermal efficiency without adequate expertise and experience can result in dangerous condensation and mould issues, so it’s essential to engage a registered Passive House consultant when pursuing this level of performance. Passive House designs will incorporate advanced breathable membranes and wall systems, thermally isolated glazing, and mechanical ventilation and heat recovery systems. While not cheap, the energy efficiency and occupant comfort achieved is remarkable.

A structural challenge with Passive House design involves developing ways to transfer structural loads across thermal zones, while minimizing the transfer of thermal energy. Typical structural members that extend from a climate-controlled interior to an external zone create thermal bridges that significantly impact performance. So, a key focus of our structural solutions for Passive House projects is the development of thermally isolated structural connections.

This result was achieved through extensive collaboration between the builder, designers and consultants, beginning at design and continuing through construction. Well done to the builder Rob Vandenberg and his team at Vital Aspect for the meticulous build, the Passive House consultant Paul Gray, building designer Steve Oke from Eco:Logical Building Design, KUSCH structural engineer Michael Dayment, Passive House certifier Jason Quinn from Sustainable Engineering, and Luc Plowman from Detail Green who performed the air-leakage tests.

A great result for the happy and comfortable clients – a husband and wife team who incidentally, have spent much of their lives working in polar adventure and logistics.

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