NatHERS for existing homes trial | Nationwide House Energy Rating Scheme (NatHERS)

We’re running a field trial of the tools and processes used to rate the energy performance of existing homes.

The trial, which is being conducted from late 2024 to late 2025, is a partnership between the Department of Climate Change, Energy, the Environment and Water (the department) and CSIRO, on behalf of all states and territories.

There are two trial streams:

Core stream – where trained trial assessors complete all elements of the assessment, including collecting data in the home, and using the trial assessment tool to produce a home energy rating and trial certificate.
Scale stream – where banks have partnered with property valuers to collect the data in the home and then NatHERS assessors work off-site to produce a home energy rating and trial certificate.

Both streams are using mobile devices with light detection and ranging (LiDAR) technology to collect data in the home and a cloud-based energy rating tool developed by CSIRO called ‘AccuRate Enterprise’ to conduct the assessment.

Household signup

By joining the trial, you’ll help shape the future of residential energy efficiency in Australia. Don’t miss this opportunity to gain valuable insights into your home’s energy use and comfort.

You can express your interest to take part in the core stream trial via CSIRO’s registration page.

If your household is selected, you will be contacted by an assessor to schedule a time to inspect your home.

For scale stream trial participants, appointments will be organised through participating banks or valuers.

Households in both trial streams will receive:

A free trial home energy rating certificate to learn how your home performs
Practical tips for energy-efficient upgrades to save on energy costs and improve the comfort of your home.

Contact us

For queries or support regarding NatHERS trials of existing home ratings, visit the CSIRO helpdesk.

Stay up to date with trials activities by subscribing to our newsletter.

Information for participating households

Trial assessment process

Households that have expressed interest to participate will be allocated to a trial assessor based on the availability of assessors servicing their area and the order in which they registered. If your home is selected, your assessor will contact you to arrange a suitable time to visit your home. During the visit, all areas of your home will be assessed, including attached garages and shading structures.

To ensure the process runs smoothly, you should take the following steps before the assessment:

Make sure all rooms and areas are easily accessible and free of clutter.
Secure any pets and open window coverings to allow clear visibility.
If applicable, provide information and evidence for recent upgrades, such as insulation improvements or receipts for renovations.

All participating households will receive a trial certificate which includes:

a star rating (out of 10)
a home energy rating (out of 100)
a breakdown of the energy used by your appliances
estimates of your home’s annual energy use and greenhouse gas emissions
the renewable energy profile for your home (if relevant).

You can use the trial certificate to:

identify areas where energy efficiency and comfort can be improved
discuss upgrades with trades, energy professionals or assessors
inform future home improvement plans, potentially increasing energy savings and comfort.

You can learn more about your ratings under the ‘Understanding your certificate’ section on the certificate page.

Trial Certificate

The trial certificate can’t be used for regulatory compliance for new homes or major renovations. Trial certificates may not be accurate, current or complete and are subject to change without notice. The trial certificate should not be relied upon for any legal or compliance purposes and is not intended to be relied on for any home upgrades.

For more information, check out the annotated certificate.

Privacy and information management

Households participating in the trial

Participation in the NatHERS trials is voluntary, and your written consent must be given prior to any home assessment. In the core stream, CSIRO collects and manages the consent of households on behalf of trial delivery partners. In the scale stream, valuers and banks collect and manage the consent of households.

You can withdraw from the trial up to the time your home’s data has been collected. After this time, it may not be possible for data to be removed from the study as it will have been deidentified.

For more information on how your privacy and household data is managed during the core stream of the trial, see CSIRO’s Research Participant Information Sheet.

For more information on privacy and household data in the scale stream reach out to the valuation firm or bank that has offered you an assessment.

If you have privacy related concerns, or wish to request removal of your personal information, please contact trials@nathers.gov.au.

How does your home compare?

Many Australian homes were built before the introduction of minimum energy performance requirements. They were also designed with little consideration of the local climate which can significantly impact the energy efficiency and comfort of a home.

Currently, the minimum star rating for a new home under the National Construction Code 2022 is 7 stars and the minimum Whole of Home rating is 60 out of 100 for houses and 50 out of 100 for apartments, noting this varies across the different states and territories.

Home energy upgrades

Quick wins such as draught proofing, better insulation, installing quality window coverings and external shading can improve comfort and reduce your energy bills. More extensive upgrades, such as full electrification of appliances and installing rooftop solar, can also save energy and money in the long term, but have higher upfront costs.

The costs, benefits and feasibility of these options will vary for each home, depending on its construction and local climate.

You will receive upgrade advice with information on options to improve your home’s energy performance following your home’s assessment, alongside your trial certificate.

Additional resources are available at:

Trial technical documents

Several technical documents underpin the software and home energy assessment method used in the NatHERS existing homes trial, ensuring a robust tool and processes.

It is important to note that these documents are for trial use only. Operational documents informed by trial findings will be published from mid-2025 for NatHERS for existing homes.

Trial Technical Note – Provides a standardised approach to rating an existing home. It details the requirements that must be followed for a NatHERS trial assessment in an existing home.
Trial Guidance Note – Provides additional guidance to support the trial Technical Note. It presents information that can assist assessors to understand the requirements.
Calculation Method – This outlines the method that underpins the NatHERS Whole of Home appliance modules and rating and has specific parameters for calculating energy use in an existing home.
Thermal Standardisation and Specification – These documents ensure the tool incorporates specific data sets, fixed inputs, validation rules, and ensures consistency and accuracy in thermal performance assessments for existing homes.

If you have feedback or are seeking access to these documents, please email trials@nathers.gov.au.