Growing up in a damp and draughty house, builder Adam Souter suffered severe asthma attacks.
Growing up in a damp and draughty housing, builder Adam Souter suffered severe asthma attacks. A generation later, when his young son developed asthma, too, he realised that poorly ventilated Australian homes where mould and bacteria flourished were making his family sicker.
Now, a healthy extension called Pepper Tree next to Souter’s 1981 brick veneer Wollongong home, by architect Alexander Symes, is one of two “passive house” projects on the shortlist of the 2022 NSW Architecture Awards’ sustainable category.
The second is CLT Passive House in Balgowlah by architect Knut Menden for the Hellier family. It was built from cross laminated timber (CLT) in about 15 hours – from its floors to walls and roof.
The temperature in Souter’s Pepper Tree – a standalone dwelling close to the old house – stays a steady 20 to 25 degrees year-round without heating or cooling. That eliminates mould and damp.
Breathing is easier, too, says Souter. “I can noticeably feel the difference compared with the humidity in our existing house, and just how uncomfortable it makes my breathing,” he said.
The Australian Passive House Association says these buildings result in energy savings of around 90 per cent compared with existing buildings because they have highly insulated and sealed walls, floors and windows, often triple or double-glazed windows. That keeps heat out in summer and retains warmth in winter.
Tents to Castles, a report released last month by the Climate Council, found low-energy efficiency standards had left too many Australians living in poorly made homes equated to “glorified tents”.
Home energy standards were worse than other countries, often a generation behind and left people with homes that were too expensive and uncomfortable to run. Excessive cold contributed to 6 per cent of deaths, double that of Sweden where temperatures plunge to minus 30 degrees, according to the report.
Builder and owner Adam Souter of Souter Built in front of his new standalone dwelling, Pepper Tree Passive House. Pic: BARTON TAYLOR
The typical Australian home is so draughty that a room’s air changes 20 times an hour making it more costly to heat and cool. In contrast, a building that meets Passive House standards has air changes of 0.6 times an hour.
Because they are so tightly sealed, they use a mechanical ventilation system which uses about the same power as one LED light - to supply fresh air, and reuse heat in the exhaust.
The temperature at David Hellier’s new passive house addition stays a steady 21 to 22 degrees in winter without any heating. “Walk across there,” he said pointing to the nearly 100-year-old Californian bungalow, “and the temperature drops to 17 or 18, four of five degrees,” he said. Even in the worst of the bushfires or heat waves, he only had to turn the air-conditioning on for an hour a day to keep the extension cool.
He envisaged his three children would sleep in the original part of the house and the adults would have the master bedroom and study in the addition.
The kids had other ideas, said Hellier. “They’re like, ‘We are moving in here’,” he said.
Menden said the use of Cross Laminated Timber made building fast, sustainable, and resulted in an airtight seal that prevented temperature swings and mould.
Architect Knut Menden and David Hellier built an addition to a 1920s Californian bungalow to comply with passive housing standards. Pic: RHETT WYMAN
He also found a huge difference in the humidity levels during record rains this year when the old part of his own home was around 94 per cent – resulting in mouldy shoes and other things – compared with 64 per cent in a new office studio extension made of CLT that wasn’t even finished. The door had yet to be installed.
Souter says the problem with passive housing as an addition is that it makes his old house – which he insulated more thoroughly nearly six years ago – less attractive in contrast.
“It’s ruined me. There are going to be more people building a passive house. And there’s no turning back. It’s like an electric car once you’ve driven one. You never want to get back in a diesel.”
Only 40 passive houses and buildings are certified in Australia, hundreds are under construction and many are attracting awards.
Some architects criticise these tightly sealed homes as un-Australian because they are removed from the elements or claim they are box ugly.
Souter’s architect Symes , who won 2021’s NSW Emerging Architect Prize for best practice sustainable design, said the unusual design of Pepper Tree showed passive houses could be as beautiful as they were sustainable.
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This article was written by Julie Power and originally appeared in the Sydney Morning Herald, May 21, 2022.