There is no doubt that the last few years have brought an increased focus on our physical and mental health. But the onset of the pandemic – and the extended periods of lock-downs that came with it – have also caused us to further consider the health of our homes and buildings. Intrinsically linked to our wellness, our interiors can help maintain a comfortable and healthy life. But what constitutes a healthy home?
“A healthy home is one that allows you to thrive without requiring you to think too much about living there,” says Kate Nason, a certified Passive House designer and the chairperson of the Australian Passive House Association. “It ensures your health and well-being are supported, that you've got access to fresh air and you're comfortable. And it allows you to protect your family against the elements outside.”
Kate is a passionate advocate of healthy and resilient buildings, and holds the role of Sustainability Advisor at Fraser Property Australia. “A healthy home should also be good for the planet,” she adds. “And it would be nice if you could run it for free!”
Passive House design can help create this kind of space. “It essentially allows you to control the temperature within the home to ensure it stays within a healthy band,” Kate starts. The band Kate refers to is between 18 and 25 degrees, and that’s the range a building has to maintain throughout the year. “Staying within that band creates a really comfortable and stable thermal environment indoors,” Kate explains.
Kate adds that constant access to fresh air is also something Passive House design prioritises. “All habitable spaces should have access to fresh air 24/7, no matter whether a window is open or not,” she explains. “We're constantly supplying fresh, pre-tempered air by recovering the energy from inside the house through a heat exchanger. As a result, you're providing fresh air and extracting stale air all the time, creating an ongoing flow of air.”
In addition, Passive House design allows the inhabitants to reduce both the energy use, and the associated bills. “That’s because you’re controlling the environment more passively, without the active heating or cooling required,” Kate explains. “You still may need additional heating in Melbourne and a little bit of cooling in Sydney, but you're actually reducing the size of your equipment by at least a quarter.“
She adds that in the right circumstances, the entire heating demand of a building can be reduced by up to 90%. “And if you've got any kind of renewable energy generation on site, you can actually get to a net positive position pretty easily,” she says, adding that it’s generally easier to achieve with a freestanding home and plenty of roof space.
Kate explains that the benefits of Passive House design have been appreciated across a range of different typologies and climates with examples she provides ranging from a hospital in Germany to an embassy building in Kinshasa. “It's applicable in any climate, any type of building, as well as any size or shape.” That doesn’t mean that the design will be the same everywhere, of course. The buildings will vary based on climate zone, even within Australia.
“If we go back to the fundamental principles, like good orientation and good shading, these will be very different in the Northern Territory compared to Tasmania because of the angles of the sun. In terms of the ventilation strategy and air tightness, there are some nuances as to which climate you're in and the direction of moisture. For example, you always put your air tightness layer on the warm side of the wall. In Brisbane, that could actually be the outside of the wall, whereas in Melbourne it's always on the inside. However, physics works the same everywhere so you just have to follow the methodology, really.”
With its multiple benefits for the inhabitants, the standard is equally as enticing for architects, designers and builders. “Passive House is a performance based standard. So it doesn't matter how you get there, as long as you prove that you can achieve the performance criteria. So it's actually quite a malleable standard and, in that sense, very appealing to architects and builders, because they can find clever ways to meet it together,” Kate explains. She also adds that once you’ve built a Passive House, there’s no coming back.
“From my personal experience working with builders to construct Passive Houses, they'll never want to go back to building a 6-star house,” she says. “They'll fundamentally have changed their perception of how to build because it’s just a better way to design. The Passive House standard is not only the most rigorous energy efficiency standard in the world, but it's also the most robust health and wellbeing supporting standard in the world, too.”
To find out more about Passive House design, listen to the full conversation with Kate Nason here.
