This provides an alternate way to meet energy efficiency requirements. It does this by setting a revised whole-of-house star rating that covers the size of the renovation or extension. This rating is calculated using an area-weighted NatHERS method. This approach reduces the need for complex redesigns, lowers costs and reduces the risk of non-compliance, making it easier for industry and homeowners to meet their energy efficiency requirements.
More information about this change (including the area-weighted NatHERS formulas) is available in the Building (ACT Appendix to the Building Code) Determination 2026 and its Explanatory Statement. The Building (General) (Alternative requirements for unaltered parts) Determination 2026 and Explanatory Statement has also been updated to support this change. This option commenced on 24 April 2026.
