Australia's homes aren’t built for a hot climate, will perform poorly as temps rise: experts

Many Australian homes behave poorly in extreme heat, a problem that will only grow as the average temperatures rise, experts say.

Australian houses are commonly either old, poorly insulated structures or new and cheaply built volume homes that can present health and economic risks to their residents in the unfolding climate catastrophe.

It comes as the Bureau of Meteorology declared Tuesday the hottest day in Australia yet with an average temperature of 40.9 degrees. The bureau says Australia has so far warmed about 1.4 degrees above pre-industrial levels.

Australian homes historically have not been well suited to the climatic conditions, Nicola Willand from RMIT’s school of property construction and project management said.

“They’re pretty standard throughout with very little adaptation to local climate,” Dr Willand said. “If you look at houses in Tasmania they’re not that different from hotter areas, in regional NSW and Victoria.

“It’s only really where you go to Northern Territory and Queensland where you see a bit of differentiation and adaptation to local climates.”

The traditional Queenslander architecture style was defined by high ceilings, wrap-around verandahs, raised structures and hallways that can act as breezeways.

Director of Architecture Australia Brooke Dunlop said that modern knowledge had superseded these older, colonial designs.

“In the past 10 to 12 years, architects have become more aware of it,” she said. “Queenslanders don’t have insulated walls. There’s a huge heat gain just because the walls are so thin.”

Ms Dunlop recently built her own home in Brisbane’s Ascot to resemble a Queenslander, but to have better thermal performance by using breezes and a shaded lower level with a concrete slab as a footing to store and move cool air around the house.

Since its completion in September, she’s turned the airconditioning on just twice.

“We’re becoming more aware and better at creating liveable solutions so we’re not so reliant on air conditioner or heating or whatever it is, that’s the challenge,” Ms Dunlop said. “My brother lives in an old Queenslander that he renovated.

“They start with the aircon on in October and they turn it off in March.”

In some cases, Australians can’t always rely on airconditioners and fans to keep themselves cool in their homes.

In past heat waves, the extreme temperatures have crippled power grids, cutting off residents from artificial cooling. Victorians were recently warned there was a risk it could happen again this summer.

Dr Willand said this led to poor health outcomes.

“If your home doesn’t perform well and you can’t rely on mechanical cooling, whether it’s due to a power outage or you’re afraid of the cost, you’re probably sitting in an overheated house and it’s a health issue,” she said.

Dr Willand said some researchers were looking into the effectiveness of building “refuge areas” in one room of the house, which should be able to stay cool in extreme events.

But she said this could be seen as a “duct tape solution” which left the rest of the house useless when the temperatures get too high.

Ms Dunlop said banks should start considering the energy efficiency rating, which includes insulation and other temperature efficiency improvements, when lending for houses to help force the improvement of Australia’s housing stock.

“We’re not seeing the banks asking for a NatHERS rating on a house just yet, which is something we need to start valuing in this proposition,” she said. “The banks will have to start valuing [an energy efficiency] star rating on houses.”

A senate committee report highlighted the dangers the climate crisis posed to Australian homes, and called for an update to national building standards and federal policy to help make the nation’s housing stock more resilient. Domain reported earlier this year the report had been ignored by both major parties.