When building a home from scratch, there are many things to consider, from location, design and affordability, but energy efficiency and reducing your carbon footprint is now more important than ever. The Passive House (Passivhaus) concept is a new way to approach your construction in a sustainable way.
Here’s everything you need to know.
Photography by Michael Tolhurst
The Passive House approach is a voluntary, global standard for buildings that focuses on creating healthier, more energy efficient and more comfortable homes and commercial spaces.
The concept originated in Europe in the 1990s and is centred around a dwelling that is designed according to specific standards, primarily separating the indoor environment from the outdoors. The term ‘passive’ comes from the building relying on external and natural influences – such as shade, sun and ventilation. Each element is carefully considered in the design and tailored to the local climate and property’s surroundings.
A Passive House design aims to reduce building energy use by up to 90 per cent and keep the inside temperature in a comfortable range between 20 and 25 degrees Celsius without the need for heating and cooling systems, which in turn drastically reduces energy consumption and costs. The design and construction principles are based on science and can be applied to buildings in any climate, giving you ultimate control of your environment and reducing your carbon footprint.
Photography by Michael Tolhurst
Ultimately, Passive House buildings are flexible – applicable to any domestic or commercial building, comfortable – offer stable temperatures all year round, healthy – are well-ventilated and supply good oxygen circulation, sustainable – reduce your energy usage and carbon footprint, controllable – tailored to the local environment and your needs, and affordable – the investment in Passive House principles is cheaper than you think.
Passive House certified designer, registered architect and Canberra local, Michael Tolhurst, has brought the principles of this design approach to the nation’s capital as the owner of Narrabundahaus, an award winning home dedicated to the Passive House concept.
Tolhurst’s single-story Narrabundah property was completed in 2021 and won the new house category in the Canberra Low Carbon Housing Challenge in the same year. The design and construction of the home is true to the strict Passive House certification criteria, with a range of sustainable features, including rooftop solar panels, rainwater collection and the reuse of the materials
from the site’s original 1940s cottage, making it a net-zero construction (or more than 100% improved) when compared to the carbon footprint of an average Canberra house. The home also has an airtight envelope and a heat exchange system that recovers up to 96% of heat and a conservatory that retains heat in the winter months and provides a space for homegrown produce all year round.
“The term ‘passive’ comes from the building relying on external and natural influences – such as shade, sun and ventilation.”
Photography by Michael Tolhurst
Tolhurst says that while sustainable design can mean different things to different people, within the building and construction industry it is the heating and cooling of our buildings that is the largest source of carbon emissions.
“Passive House design focuses on thermal comfort, indoor air quality and energy efficiency, so for me as an architect, I feel it ticks a lot of boxes in terms of sustainable design,” he says.
It is important to understand that the Passive House standard is a holistic approach, says Tolhurst, based on building physics and the movement of heat and moisture within a building.
“The Passive House approach incorporates five construction principles that all work together to create a comfortable and healthy home. They are: high performance windows, continuous thermal insulation, no air leakage, mechanical ventilation with heat recovery and no thermal bridges,” he says.
“This is verified through detailed modelling using the project using the Passive House Planning Package (PHPP). Unlike the NatHERS star rating system, the Passive House standard also requires ‘as-built’ verification (including airtightness testing), which provides quality assurance that the home will perform extremely well.”
For anyone who is only just starting out on their new home journey, Tolhurst says to firstly educate yourself on the benefits of Passive House and what it involves.
“The Australian Passive House Association website is a great place to start for resources and events. There’s a growing community of advocates who are usually only too happy to share their knowledge and experience. For those who are closer to actually starting a project, it is very important to have a qualified Passive House designer on your team from the early design stages who will be responsible for the PHPP modelling.”
Tolhurst also recommends attending an open house day to experience what a Passive House feels like firsthand.
“The International Passive House Open Day is a great opportunity to learn more about the approach, which is held twice a year. The next open day is 11–13 November 2022. The Sustainable House Day is also another opportunity, with the next event scheduled for 19 March 2023.”
