There have been calls for these minimum standards to be raised. However, many policymakers and building industry stakeholders believe the market will lift performance beyond minimum standards and so there is no need to raise these.
What did the data show?
We wanted to understand what was happening in the market to see if consumers or regulation were driving the energy performance of new housing. To do this we explored the NatHERS data set of building approvals for new Class 1 housing (detached and row houses) in Australia from May 2016 (when all data sets were integrated by CSIRO and Sustainability Victoria) to December 2018.
Our analysis focuses on new housing in Victoria, South Australia, Western Australia, Tasmania and the ACT, all of which apply the minimum six-star NatHERS requirement. The other states have local variations to the standard, while New South Wales uses the BASIX index to determine the environmental impact of housing.
The chart below shows the performance for 187,320 house ratings. Almost 82 per cent just met the minimum standard (6.0-6.4 star). Another 16 per cent performed just above the minimum standard (6.5-6.9 star).
Only 1.5 per cent were designed to perform at the economically optimal 7.5 stars and beyond. By this we mean a balance between the extra upfront building costs and the savings and benefits from lifetime building performance.