What is NatHERS Whole of Home?

NatHERS now includes a new Whole of Home rating that measures the energy use of the whole home including appliances, solar and batteries.

This is the biggest update to the Scheme since it began 30 years ago. It will support important energy efficiency improvements for new homes across Australia. Designing and building new energy efficient homes supports the economy’s transition to net zero emissions by 2050.

The new Whole of Home rating can be used to demonstrate compliance with the increased energy efficiency requirements in the National Construction Code 2022, recently announced by Building Ministers. The key changes are adopting a minimum standard of 7 stars and the introduction of an annual energy use budget.

NatHERS Whole of Home ratings provide an easy to use rating to show how the home meets or beats the new NCC annual energy use budget which requires consideration of the efficiency of the appliances used in new homes and solar and batteries.

Adding to the current NatHERS star rating assessment out of ten, the Whole of Home Performance Rating will be a separate rating out of 100.

The new assessment builds on the thermal performance assessment by providing information about the energy use of the following appliances:

  • Heating and cooling
  • Hot water systems
  • Lighting
  • Pool/spa pumps
  • Cooking and plug-in appliances
  • On-site energy generation and storage.

The rating considers energy used for heating and cooling, and appliances, minus energy generated from solar panels, building a useful energy snapshot of energy costs as well as greenhouse gas emissions.

While the Whole of Home rating scale ranges from 1 to 100 (where 100 is a net zero energy value home), ratings above 100 are possible. One way that a home may rate over 100 is where a home generates more energy than it uses.

Benefits of expanding NatHERS

The changes to NatHERS will help lower energy use and bills for households across Australia, while also ensuring comfortable and resilient homes for the future.

The expansion is supporting the reliability of the energy grid, and a range of initiatives, such as the finance sector using NatHERS to underpin green loan products. 

The updates will also support industry and home owners to design beyond minimum standards to achieve zero energy (and carbon) ready homes, as outlined in the Trajectory for Low Energy Buildings, and its Addendum.

Alongside the development of Whole of Home ratings and assessments, the Scheme is also being extended to include assessments and ratings for established homes.  

Phased transition 

NatHERS Whole of Home assessments and ratings will be gradually phased in with a transition period.

Release (September 2022 – October 2022)

To support the launch of Whole of Home and thermal updates a revised suite of documentation is being released. Documents include:

Modification (September 2022 – October 2023)

This phase will allow for any final adjustments to accredited NatHERS tools and guidance to support NCC 2022 requirements. Accreditation of tools will be ongoing as applications are received.

Training will be available for accredited assessors. For more information subscribe to the NatHERS Newsletter or check the website.  

Software updates and accreditation

The benchmark tool now enables an assessment and rating of a home’s appliances. It has been designed to align with the NCC 2022 energy efficiency requirements.

Software developers need to demonstrate that the Whole of Home modules within their software tool meet the relevant provisions of the Software Accreditation Protocol (SAP). This will ensure that Whole of Home software tools meet the standard requirements and produce consistent and reliable assessments and ratings that are nationally comparable.

An updated version of the NatHERS SAP will be released to coincide with NCC 2022 announcements.

Find out more about the benchmark tool.

Updated certificate

New NatHERS certificates have been developed to include Whole of Home ratings and to support the NCC 2022 energy efficiency provisions.

Learn more about the updated NatHERS certificates.

For further information on Whole of Home changes see Frequently Asked Questions