Air-Free Home Project Aims to Inspire Energy-Efficient Building in New Perth Suburb

From the outside, this show home in Brabham, a newly developed suburb in Perth’s outer east, looks much like the other project homes on the street with its freshly painted walls and new garden.

But this three-bedroom home has been assessed a 9.2-star energy rating by CSIRO’s National Home Energy Rating Scheme (NatHERS).

That makes it the highest-rated two-story house in the country, according to Mick Fabar, chief executive of Green Homes Australia, which built the house.

The exterior of the 9.2 star Brabham house.
The Brabham house is made of a light timber frame.(ABC Radio Perth: Emma Wynne)

He hopes that having a prototype that people can see for themselves will encourage them to commission buildings that use much less energy.

“That’s why we’ve built this house, so they can come in, come on the hottest day and see what it’s like,” Fabar said.

No air conditioning experience

The house, which is built with a lightweight wood frame, has all the elements commonly associated with green living: a light-colored roof, solar panels, battery storage, and double-glazed windows.

Significantly, it has no air conditioning, only ceiling fans.

Positioning of windows and ceiling fan of the house
The house relies on ceiling fans and window placement for much of its heating and cooling.(ABC Radio Perth: Emma Wynne)

But Fabar said it was the less conspicuous elements that made the biggest difference to the house, like the polished concrete floor that runs through the ground floor and provides the most important thermal mass.

“Concrete is absolutely beneficial; you have to have thermal mass in a house to mediate temperature, whether you’re in a hot or cold climate.

“Thermal mass is needed to be able to take energy out of the environment, out of habitable space, and then put it back at night.”

Additional thermal mass is achieved with an interior brick wall – the construction team opted to leave it unplastered when told that leaving it would bring the house down from a 9.1-star rating to 9.2.

Interior of a 9.2 star house with brick walls and windows
Left a brick wall unrendered to increase the star rating.(ABC Radio Perth: Emma Wynne)

The second element is the positioning of double-glazed windows for passive cooling and heating.

“All the windows have been calculated to be in the right position to not allow summer sun into the house, but allow the right amount of winter sun, so that’s a critical calculation,” Fabar said.

“We have fans to cool in the summer, and in the winter the design is really about that winter sun and heating up that thermal mass and using it to heat the home.”

plugging leaks

The design has also focused on an element that is often overlooked in Australian homes: airtightness, meaning that once the house heats up or cools down, it stays that way.

“You don’t want to create a living environment and then have air seeping under doors and under baseboards and through power points and windows,” Fabar said.

“In Australia, we have a terrible history of houses leaking (5, 6, 7 percent) and there is no standard.”

The show house aims to have air leakage of less than 1 percent.

“It’s a really simple construction science, but not too difficult, it’s just that builders aren’t applying it,” Fabar said.

All doors and windows are double glazed with hermetic seals.
All doors and windows are double glazed with hermetic seals.(ABC Radio Perth: Emma Wynne)

Everyone involved in the project is aware that spending hundreds of thousands of dollars on a new home without cooling at the flick of a switch can be a hard sell, especially in an area 20 kilometers inland where summer sea breezes take time to settle. get.

But builders and developers are hoping the potential savings on electricity bills and the chance to see if it works will be tempting.

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