In 2022, the National Construction Code introduced an annual energy use budget for new residential buildings. The Whole of Home rating is used to demonstrate compliance with this energy efficiency requirement. It measures the energy use of the entire home including appliances, solar and batteries.
This table shows which states and territories are implementing NCC 2022 energy requirements.
The updates are supporting industry and home owners to design beyond minimum standards to achieve zero energy (and carbon) homes, as outlined in the Trajectory for Low Energy Buildings, and its Addendum.
Building on star ratings
Adding to the NatHERS thermal star rating out of ten, the Whole of Home assessment is a separate rating out of 100. It is a useful snapshot of home energy costs as well as greenhouse gas emissions.
A Whole of Home rating considers the following appliances:
- hot water, heating and cooling systems
- lighting, cooking and plug-in appliances
- pool and spa equipment
- solar energy generated onsite and battery storage.
While the scale ranges from 0 to 100 (where 100 is a net zero energy value home), ratings above 100 are possible. One way a home may rate over 100, is where it generates more energy than it uses, for example via a larger than average solar system.
Assessors can visit the assessor toolkit page for additional information about training, and Whole of Home software including a calculation method, guidance and technical notes.
See examples of NatHERS certificates here.
For further information, see Frequently Asked Questions.
Software updates and accreditation
The CSIRO’s benchmark tool has been designed to align with current NCC energy efficiency requirements in accordance with the NatHERS Software Accreditation Protocol (SAP).
Software developers must demonstrate that Whole of Home modules within their tools meet the SAP provisions. This ensures nationally comparable and consistent ratings that meet NCC requirements. Software tools meeting the provisions of NCC 2022 are listed at Software updates.