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.
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.
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.
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.
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.
construction cost
Fabar did not disclose how much the house cost to build, but said it was in the low $500,000 range and not significantly more than a comparable house.
“Building an energy-efficient home doesn’t necessarily cost you more money if you design it correctly,” he said.
“Traditionally, we’re seeing a 2 to 3 percent increase in the cost of building a sustainable, energy-efficient home.”
But the savings in the coming years are expected to be significant, he added.
“Everyone lives differently. Some people sleep with the lights on or shower for two hours, but based on the national average, energy use will be reduced by 70 percent.”
To find further evidence of its efficiency, researchers from the University of NSW will study the house, both as a show home and when occupied to obtain data on actual energy use.
Paul Lakey, regional general manager for Peet, the joint developer of the Brabham Estate with the state government, said the ongoing costs of running a home were becoming more pertinent to buyers.
“One of the biggest things that people need to figure out when looking to build a home is the life of the home,” Lakey said.
“If you can save several thousand dollars a year in energy efficiency and costs per year, then that’s a good way to go. Over 20 years that adds up.
“The cost of energy is not going to go down anytime soon. This is a big factor in terms of the cost of living going up right now.”
“If you can keep those ongoing recurring costs down in a simple way without affecting your standard of living, then that has to be a good thing.”
Leave a Reply