According to industry experts who presented at a workshop hosted by engineering and infrastructure advisory company Aurecon and Monash University in April, passive house construction can have a significant impact on the quality of buildings and comfort for occupants, when successfully implemented.

Improved building outcomes, such as greater levels of thermal comfort, a healthier work environment, lower energy costs and increased building structure longevity can all be achieved when following the Passive House Building Standard.

Aurecon ESD consultant Johanna Trickett said that passive house construction provided high comfort and quality of life without sacrificing energy efficiencies or increasing costs.

“Australia and New Zealand are at the start of this journey and due to initial obstacles and challenges, such as a knowledge gap in industry as well as availability of products and materials, the Passive House Building Standard will likely incur greater costs than will be the case once this standard becomes normalised. However, the passive house benefits of user comfort and energy efficiency outweigh the costs,” says Johanna.

“The Passive House Building Standard is applicable to any construction and provides a quality benchmark for health, comfort and performance.”

Pro Clima Australia building science manager Jesse Clarke says that the emerging issues that minimal compliance buildings face include moisture and mould in cooler climate locations, and increased summer cooling issues in warmer climate locations.

“The Passive House Building Standard has solved both of these issues by delivering comfort through control over thermal fluxes over the building envelope, combined with adequate thermal bridging. This provides stability of indoor conditions,” says Jesse.

“Through air tightness considerations and implementation of the building standard, we see a balance in the moisture flows with the heat within the building envelope which results in a healthy, dry, high performing building.”

Aurecon associate Susanne Hundert explains that passive house construction required very high levels of building fabric airtightness to provide the thermal comfort and low operating costs expected.

“The responsibility of delivering a successful passive house sits with every project team member involved. It is crucial for all to be open, transparent, communicative, and to effectively work as a team,” says Susanne.

Fantech intelligent ventilation solutions engineer Joel Seagren says that improved health was achieved from factors such as enhanced indoor air quality and the greatly reduced requirement for supplementary heating and cooling.

“This reduces the risk of allergy and dehumidification effects that can be associated with HVAC air delivery systems,” says Joel.

“While ventilation requirements are well prescribed for some building classes (but not all), the importance of correct ventilation is increased as there can be no reliance on fresh air infiltration via the building fabric. While this is not explicitly included in the design, it can have a meaningful impact in terms of indoor air quality, condensation removal, and potentially mould growth.

“Direct ventilation, mechanical or natural, increases the required capacity of heating and cooling equipment when outdoor air temperatures, or humidity levels, are outside comfort bands, which is typically most of summer and winter depending on the climate zone.”

With efficiencies stated to be between 80-90% for high quality heat recovery units, this allows for a significant reduction in heating and cooling plant capacity, energy consumption, and therefore operational costs.