It sounds like it's from an episode of a TV architectural show: an airtight house fitted out with $60,000 worth of double-glazed windows imported from Poland.
But Toowoomba couple Michael Krause and Meegan Symonds have had to hose down expectations from friends and family.
"They've all seen Grand Designs, so they all envisage a huge house and I had to play it down a bit and say it's just a normal house," Mr Krause said.
The couple's new two-bedroom, one bathroom house, being built on a 380-square-metre parcel of land at Harlaxton in Toowoomba's northern suburbs, is set to become the southern Queensland city's second passive house.
The concept, developed in Germany in the 1990s, is gaining popularity in Australia, with the number of certified passive homes increasing from 25 in 2019 to 52 in 2022.
For a building to be certified as a passive house, it needs to meet several criteria including airtightness and for temperatures to remain around 25 degrees Celsius.
Building materials
Mr Krause and Ms Symonds' new home includes double-glazed windows filled with argon gas and thermal breaks, to stop heat from coming into the building.
It will also have thicker, heavier duty insulation wrapped over the house and a heat-recovery machine fitted with medical-grade filters, to keep temperatures stable.
And unlike many homes in Toowoomba, it'll only need a small 5-kilowatt ducted air conditioning system, powered by solar panels, to deal with southern Queensland's seasonal extremes.
Ms Symonds said they first looked at the concept because they wanted to have a low impact on the environment.
"When we bump into someone and say we're building and then we explain about passive houses, it's something a lot of people haven't heard of at all."
She said the designed house seemed comfortable and the use of filtered air met the health needs of her husband, who had asthma.
The couple had been concerned about extra costs, but Ms Symonds said quotes for the project ended up only about 10 per cent more expensive than a traditional build.
"In all honesty, the cost of building a passive house is not a lot more, once we worked that out, there was nothing that was really stopping us from doing this."
Ms Symonds said the project has since managed to stay within their $510,000 budget for the house.
Growing interest
The Australian Passive House Association said the couple were part of the growing number of homeowners, builders and designers interested in the concept.
CEO Alexia Lidas said demand was outpacing the number of skilled professionals who could build the homes.
"We're growing 20 per cent year on year," Ms Lidas said.
She said along with the concept's environmental credentials, people were also interested in passive homes because of the verification process.
Nathan Peters, director of Titanium Homes, built Toowoomba's first passive house and is helping Mr Krause and Ms Symonds with their build.
He said he'd seen an increase in enquiries as well.
"I've got another two three-bedroom ones I'm quoting at the moment, I quoted one last month out near Dalby, so there's definitely a bit of interest."
The way of the future?
Mr Peters said a passive-house build required a lot more attention to detail and better planning.
"There's a lot of thought that goes into it to try to get all the wraps really done well and get the house totally airtight," he said.
"The trades need to be thinking a lot more about their workmanship and making sure they take a lot more care."
Mr Peters said he thought the passive-house concept was the way of the future, as energy efficiency and climate change became bigger considerations for buyers.
Michael Krause also expects to see more passive houses in Australia, given the concept works well in both warm and cold climates.
"I think it will be a lot more common because people will realise once they come in just how comfortable they are versus the traditional home where you've got those extremes," he said.
"You'll find a lot more people will be looking at building, especially once they realise that the costs aren't prohibitive."
