She said there will likely be more homes with light-colored roofs, insulation and better quality windows, but for some homes it might be as easy as swapping out the design to upgrade it from six to seven stars, for example by moving one Garage off north wall.
“Instead of your garage protecting your home from the winter sun, move your garage.”
Projected cost impact modeling is due this week and should yield an average capital cost of $2,200 per new build.
Homeowners also save money on their energy bills over time, and Rooney said owners could expect to get $1.30 back for every dollar spent over the long term.
NSW modeling this week found energy bills for new high-rise housing in suburban Sydney could fall by $150 a year and $720 for homes in western Sydney under the change.
A 2019 to learn Sustainability consultants Renew found that the payback period for choosing a seven-star, solar-powered Melbourne home over a six-star was less than five years.
Building scientist Jenny Edwards, director of Light House Architecture and Science, said that in some cases it doesn’t cost more to go from six to seven stars.
She’s seen owners fall in love with a design, build it on their block without thinking about direction, and realized the only way to make it more energy efficient is to spend money on it, for example by improving insulation .
Instead, she says, it makes more sense to respect the original design, placing most windows on the north side and shading all west windows with retractable blinds or landscaping.
“None of this is rocket science, it’s really basic stuff,” Edwards said.
“It’s fairly easy to get to seven stars in most parts of Australia. Tasmania will be the biggest challenge, and the ACT and Victoria.”
Her own house in Canberra has an 8.2 star rating and Edwards could have paid the same amount for a six star project house but was able to reduce its energy needs by making the four bedroom house slightly smaller and more space efficient.
She said there would be some instances where upgrading cheap single-pane windows to double-pane windows could cost as much as $15,000, but many owners don’t need to do that.
Ken Morrison, chief executive of the Property Council of Australia, backed the change, saying it would reduce energy bills and some upfront costs would come down quickly.
“The glazing you are allowed under the existing regulations is cheaper than the glazing you will need afterwards, but once supply of these products becomes the norm, the unit price of these products will also go down,” he said.
Morrison called for better quality assessment tools to help homeowners understand how efficient their homes are and incentives to encourage higher quality buildings.
“Why not pay less stamp duty if you have a more energy efficient home?” he said.
Nicola Willand, RMIT Senior Lecturer at the School of Real Estate, Construction and Project Management, said the change would help both renters and owners, but warned that even seven stars is less than other countries have achieved.
She encouraged new homeowners to increase their building’s energy efficiency beyond seven stars whenever possible as the climate gets warmer.
“It’s that shell that needs to be as good as possible when you build it because it’s going to be locked in for decades,” she said.
“You can still change the kitchen after five or ten years, but changing the building means opening the walls.”