Certified Passive House is a growing trend in Australia but what exactly does that mean and why are people embracing this voluntary building standard?

A passive house is one that delivers a healthy indoor environment that is comfortable in temperature and humidity, while using very little energy. Originating in Germany in 1990 where it is known as Passivhaus, it is already widely used across Europe and, while a relatively new idea here in Australia, very much a growing trend due to its many cost and health benefits.

While some people think of a Passive House as one where all the windows and doors are never opened, it is not an enforced sealing up of a building, in fact quite the opposite. You can open the doors and windows when the weather is nice and close it up when it is too hot or cold – essentially live like you usually would. The difference is when it is uncomfortable outside and the house is closed, it is sealed, and you are getting the optimum indoor environment when it comes to health and comfort.

What makes a house a Passive House?

There are five design principles to a passive house which set limits on energy use and air leakage.

Thermal Insulation

The exterior envelope of the house must be very well insulated.  Your project will depend on the climate zone, a house in Cairns will be different to a house in Melbourne.

Airtightness

Airtightness of the building controls air leakage through gaps, an airtight building significantly assists energy savings – depending on your location, whether trying to keep the heat or cold in or out, less energy is required to do that in a passive house.

High-Performance Glazing

Well insulated performance-based glazing generally low-e glass, double or triple glazed units are required to prevent heat transfer. Windows are the weakest point in the thermal envelope when trying to maintain our thermal comfort zones.

Thermal-bridge Reduced Design

This is a complicated principle, but simply put thermal bridges are the points where conventional buildings lose energy. These thermal bridges are weak points in the building that result in high chance of moisture/mould while fast tracking energy losses through the building envelope.

Heat Recovery ventilation

A ventilation system consistently supplies fresh air making for superior air quality without causing any unpleasant draughts. A highly efficient heat recovery unit allows for the heat contained in the exhaust air to be re-used. Passive House buildings are also praised for their high level of comfort. They use energy sources inside the building such as the body heat from the residents or solar heat entering the building – making heating a lot easier.

At Alexandra Buchanan Architects, two of our very talented team members, Jimi Connor and Adam Hamilton, are Passive House accredited through the internationally recognised Passive House Institute. If you have any questions regarding Passive Housing, whether it’s for a new build or a renovation, please contact us at studio@alexandrabuchanan.com and James and Adam will be able to assist you.