CANBERRA: Australia’s national home energy “report card” is set to be expanded to cover existing homes, as advocates renew calls for energy ratings to be disclosed when properties are sold or leased. The federal government has committed A$32.7 million to broaden the Nationwide House Energy Rating Scheme, known as NatHERS, so more households can obtain a rating and a certificate that outlines the home’s energy performance and potential upgrade options.
NatHERS has been used for about 30 years to rate the energy efficiency of new homes. The scheme assesses factors including a home’s design, orientation, insulation, construction and thermal performance, and also takes account of energy used by fixed appliances and energy generated on site, such as from rooftop solar. Accredited assessors collect information for modelling in NatHERS software, producing a Home Energy Rating Certificate designed to help owners understand running costs and practical improvement pathways.
NatHERS ratings are expressed on a 0-to-10 star scale, with 7 stars adopted through the National Construction Code as the minimum standard for new builds in most jurisdictions. The government says around 70% of Australia’s 11 million existing homes were built before minimum energy efficiency standards were introduced, with an estimated average rating below 3 stars. It says lifting a home from 3 to 5 stars can reduce the energy needed for heating and cooling by around 40%. Trials have involved energy assessors, CSIRO, valuers and four major banks, with the next expansion phase due from mid-2026.
Disclosure framework
Energy ministers released an updated Home Energy Ratings Disclosure Framework in December 2024, setting out a national approach for jurisdictions that choose to require ratings to be provided at the point of sale or lease. Version 2 extends the framework to cover apartments and apartment buildings as well as single dwellings, and outlines policy parameters intended to support consistent disclosure schemes across states and territories. The accompanying cost-benefit analysis released with the framework found a net benefit for implementing mandatory disclosure at sale or lease, subject to scheme design.
Calls for mandatory disclosure have continued as the rating system expands. In South Australia, the Royal Automobile Association urged the state government to require energy efficiency ratings for all homes at the point of sale or lease, arguing the information should be available to buyers and renters before they sign contracts. In New South Wales, the state and federal governments have trialled how a home energy rating could be used in sale or lease advertising, with the pilot designed to test processes and training resources for the property sector and to inform any transition from voluntary to mandatory disclosure settings.
Existing homes transition
Australia already has a long-running mandatory disclosure model in the Australian Capital Territory, where a legislated Energy Efficiency Rating scheme has required ratings to be disclosed since 1999. NatHERS has said its existing-homes ratings are not currently compatible with the ACT’s legislated requirements, which specify particular standards for software, assessors and certificates. It has said the ACT government is monitoring NatHERS development as the national program expands.
The expansion also coincides with the planned closure of the Residential Efficiency Scorecard program on 23 June 2026, with governments shifting focus to NatHERS as the national framework for rating existing homes. NatHERS has set out a Stage 2 release for mid-2026 that includes updated, second-generation software and assessment methods, an updated Home Energy Rating Certificate with upgrade guidance tailored to the property, and training and accreditation pathways to open access to a wider pool of assessors. The department said the certificate can be used by owners and, where disclosure rules apply, shared with prospective buyers and renters. – By Content Syndication Services.