Isometric scale model of an older weatherboard cottage cut away to show ceiling insulation and wall framing, with a blower door fan in the front doorway.

NatHERS for existing homes: the assessment pathway explained

In short

  • NatHERS now presents to households as Home Energy Rating, with a new website at homeenergyrating.gov.au from 1 July 2026. Existing homes assessments are live, and householders can book one through the Find an Assessor tool.
  • Existing homes is a separate accreditation stream. Design Matters National manages it as the Assessor Accreditation Service Provider (AASP). New homes accreditation still runs through three AAOs: ABSA, Design Matters National and HERA.
  • An existing homes assessment is done on site and produces a certificate with a Home Energy Rating (0 to 100+), a Star Rating out of 10 and upgrade guidance.
  • Free accreditation and membership are on offer until there are 150 accredited existing homes assessors, and a limited number of funded training places run from July to December 2026.
  • It is not a compliance rating. A major renovation that must meet the NCC still needs a new homes certificate, and in the ACT an existing homes assessment cannot yet be used for the Energy Efficiency Rating disclosure scheme.

Correct as at September 2026.

For years, NatHERS meant one thing to most assessors: rating a set of plans before anything was built. That is no longer the whole job. The scheme now rates homes that already exist, as they stand today, and the programme has moved from trial to open accreditation.

What changed in 2026

On 1 July 2026 the Australian Government launched the Home Energy Rating website, replacing nathers.gov.au. NatHERS is still the scheme underneath, but the public name is now Home Energy Rating. You will see new homes certificates labelled “Home Energy Rating (NatHERS) for new homes” and the newer product labelled “Home Energy Rating for existing homes”.

The same month, training and accreditation for existing homes opened to anyone who wants to become an assessor, not just the early cohorts. In late July 2026 the Home Energy Rating news page announced funded training places and free accreditation to grow the workforce. The rollout is over. It is running.

How existing homes differs from new homes

New homesExisting homes
What is ratedThe design, from plans and specifications, before constructionThe building as it stands, including its fixed appliances and any solar or battery
HowDesk based modellingA site visit of about 2 to 3 hours, then modelling
OutputStar Rating used for NCC complianceHome Energy Rating (0 to 100+), Star Rating out of 10 and upgrade guidance
AccreditationOne of three AAOs: ABSA, Design Matters National or HERAThe AASP, Design Matters National
RulebookNatHERS Technical Note (new homes)NatHERS Technical Note for existing homes (version 20260701)

In short, a new homes rating predicts how a design will perform. An existing homes rating describes how a real house performs now, additions and wear included.

Who accredits existing homes assessors

For new homes, you apply to one of three Assessor Accrediting Organisations: ABSA (Australian Building Sustainability Accreditation), Design Matters National or HERA (House Energy Raters Association). ABSA is run through BDAA, but BDAA itself is not an AAO.

Existing homes accreditation works differently. It is managed by a single Assessor Accreditation Service Provider, Design Matters National. DMN handles accreditation and renewals, CPD, technical enquiries and complaints, and assessor performance. New homes accreditation does not carry over automatically. You need existing homes accreditation to issue an existing homes certificate.

Already accredited for new homes? You can use the streamlined pathway below, and if you win one of the free places you pay nothing extra for existing homes accreditation. You still pay membership to your chosen AAO for your new homes accreditation.

Training: full and streamlined pathways

Two Registered Training Organisations deliver the training: Northern Victoria Institute of TAFE and Transformed.

New entrants complete seven units of competency from the Certificate IV in Home Energy Efficiency and Sustainability (CPP41126), the Home Energy Rating unit “Conduct Home Energy Rating assessments for existing homes”, and training in the software they will use. Recognition of prior learning may be available.

A streamlined pathway is open to people already doing home energy assessments: accredited new homes assessors, licensed ACT Energy Efficiency Rating assessors, and Residential Efficiency Scorecard assessors who were accredited when that program closed on 23 June 2026. They complete the Home Energy Rating unit, software training and CPPCOM4002 (safe work practices in the property industry), or show they have already done it.

After training you apply to the AASP, pass a criminal history check and the accreditation exam, and show professional indemnity cover of at least $2 million and public liability cover of at least $10 million.

Software and data collection

Existing homes ratings are calculated on a CSIRO platform. The benchmark tool is AccuRate Enterprise (existing homes mode), and commercial providers can build interface tools that connect to it under the User Interface Protocol. A customised version of the magicplan app can export site data into AccuRate Enterprise, but it is optional and is not NatHERS accredited.

That is separate from the new homes software list, which is currently AccuRate Home, BERS Pro, FirstRate5 and Hero.

On site, the Technical Note for existing homes sets the rules. The ones that shape your day:

  • Evidence. You must collect photo and documentary evidence to the Technical Note’s requirements, for audit and quality assurance.
  • Standard settings. For some inputs you may apply standard settings (typically averages) to save time and keep ratings comparable.
  • Default values. Where you cannot confirm a component, such as insulation in a raked ceiling, you must apply default values, which are typically worst case. You must document and justify them, and tell the client they may pull the rating down.
  • Consent and access. The client signs the Client Information and Consent Form for every assessment, and you must get permission from the person on site before you enter.

Staying accredited

Under the Code of Practice, existing homes assessors must complete at least 12 CPD points, 6 of them technical, and submit at least 3 existing homes assessments in a software tool they are accredited to use. Insurance must stay current, and any performance improvement actions must be completed.

Disclosure: where ratings are required

The ACT has required disclosure since 1995, and its scheme is the working model most people point to. A home’s Energy Efficiency Rating (EER), a star rating out of 6, must appear in all sale advertising, and the EER statement goes with the sale contract. If a home already has an EER statement and has not changed, the rating must also be shown when it is advertised for rent. A licensed ACT building assessor prepares the EER, usually in FirstRate 4. ACT Planning says an existing homes assessment does not currently meet ACT requirements for an EER statement, although the program may be considered for ACT disclosure law in future.

Nationally, energy ministers have agreed a Home Energy Ratings Disclosure Framework that states and territories can implement for sale or lease. NSW is building ratings into its Home Energy Saver program and piloting subsidised assessments. Outside the ACT, check what your state or territory has actually legislated before you tell a client a rating is required. Plan for disclosure, but do not promise it is law until it is.

Is it worth adding to your practice?

For many assessors, yes, if you price it properly. The market is the whole existing housing stock. Demand comes from households planning upgrades, sellers and landlords, installers of solar and batteries, and green loan and rebate programs that ask for a rating.

It is a different job, though. Travel, 2 to 3 hours on site, photo evidence and report delivery all take time that a desk based new homes rating does not. Price from the full workflow, not the modelling alone, or your margin disappears.

Where CPD On Demand fits

CPD On Demand courses are recognised CPD designed for assessors. Each course runs one hour, and your certificate is issued the moment you finish. Whether a course counts toward your technical points is up to your accrediting organisation. These live courses cover the existing homes shift:

Plan your CPD year around the new work. Our CPD requirements guide sets out the rules for every profession, and the CPD deadlines calendar shows the dates coming up. Browse all energy assessor courses.

Frequently asked questions

What is a NatHERS existing homes assessment?

It is an on-site assessment of a home that has already been built. An accredited assessor collects data about the building, its fixed appliances and any solar or battery, and produces a certificate with a Home Energy Rating (0 to 100+), a Star Rating out of 10 and upgrade guidance.

Is NatHERS now called Home Energy Rating?

Home Energy Rating is the public name used since the new website launched on 1 July 2026. NatHERS, the Nationwide House Energy Rating Scheme, is still the scheme behind it, and new homes certificates are labelled Home Energy Rating (NatHERS).

Who accredits existing homes assessors?

Design Matters National, as the Assessor Accreditation Service Provider. New homes assessors are accredited by one of three AAOs: ABSA, Design Matters National or HERA.

Does my new homes accreditation cover existing homes?

No. You need separate existing homes accreditation. Accredited new homes assessors can use a streamlined training pathway: the Home Energy Rating existing homes unit, software training and CPPCOM4002 safe work practices.

Can an existing homes rating be used for NCC compliance?

No. Where a major renovation must meet the NCC, a Home Energy Rating (NatHERS) for new homes certificate is used. An existing homes rating describes the home as it stands.

Is energy rating disclosure mandatory when selling a home?

In the ACT, yes. An Energy Efficiency Rating must be shown in sale advertising and, for homes that already have one, in rental advertising, and an existing homes assessment cannot currently be used for it. Elsewhere, states and territories are working from the national Disclosure Framework, so check your jurisdiction before advising a client.

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