Fake NatHERS Certificates: Spot a Fraudulent Energy Rating

A fraudulent NatHERS certificate is a Nationwide House Energy Rating Scheme report that misrepresents a home's genuine thermal performance — either because the accredited software was fed inflated inputs (insulation, glazing, orientation) to clear the 7-star minimum without the matching building work, or because the "assessment" was never carried out against the actual dwelling at all. Unlike the United Kingdom's single national EPC mandate, Australia runs a patchwork: NatHERS governs new-build compliance everywhere under the National Construction Code, while mandatory disclosure at the point of sale or lease exists in full only in the ACT, is mid-trial in NSW, and is still under consideration in Victoria — which means the fraud incentive and the verification path both differ depending on which state a property sits in.

This article is provided for informational purposes only and does not constitute legal, financial, or regulatory advice. Regulatory references are accurate as of the publication date. Consult a qualified professional for guidance specific to your situation.

Why NatHERS fraud risk exists in Australia

The National Construction Code 2022 lifted the minimum thermal performance for new Class 1 homes from 6 stars to 7 stars, with the change commencing 1 May 2023 and phased in as mandatory from 1 October 2023 across most participating states and territories (ABCB, NCC 2022 edition). A property that assesses as a genuine 6-star design under the old benchmark needs real upgrades — better insulation, improved glazing, tighter sealing — to reach 7 stars, and those upgrades commonly add tens of thousands of dollars to a build, which is exactly the gap a manipulated NatHERS input file is designed to paper over without anyone touching a wall.

NatHERS itself is not a single certificate scheme but a rating produced through one of several accredited software tools (AccuRate, BERS Pro, FirstRate5, or HERO) by an individual accredited through a NatHERS Assessor Accrediting Organisation (AAO), such as the Association of Building Sustainability Assessors (ABSA) or Design Matters National. Every accredited assessor is required to hold a Certificate IV in NatHERS Assessment, carry professional indemnity insurance, and submit assessments for quality-assurance auditing when requested by their AAO (NatHERS, assessor accreditation and qualifications). That audit trail is the mechanism that catches manipulated ratings — but only if someone checks.

The three ways a fake rating actually gets made

Fraudulent NatHERS documentation tends to fall into the same three patterns seen across other accredited-assessor schemes, and which one is in front of you determines how you verify it. Assessor Accrediting Organisations are required under the NatHERS AAO Protocol to run annual quality-assurance audits of accredited assessors' reports, with unsatisfactory conduct grounds for suspending or revoking accreditation (NatHERS, AAO Protocol) — which is the mechanism behind all three patterns below, whether or not it catches a given certificate before it reaches a buyer.

• Desktop-only ratings with no genuine site visit. For an existing home, a proper assessment requires the assessor to inspect insulation, glazing, orientation, sealing, and construction materials on site before running the data through NatHERS-accredited software. A rating produced entirely from a floor plan, or from a previous owner's decade-old data, skips that step and can misstate the building's real performance by a full star band or more.
• Manipulated inputs on a genuine software run. The software itself is not the weak point — the numbers fed into it are. An assessor who overstates wall or ceiling insulation thickness, glazing performance, or air-tightness produces a certificate that is technically generated by approved software but does not reflect what was actually built, the same failure mode UK regulators have pursued Domestic Energy Assessors for under EPC rules.
• Certificates from someone not on the Assessor Register at all. NatHERS publishes a public Assessor Register precisely so a builder, buyer, or certifier can confirm the individual named on a certificate is currently accredited (NatHERS, Assessor Register). AAOs can suspend or revoke accreditation while investigating unsatisfactory conduct, and a certificate from someone who isn't listed, or whose accreditation has lapsed, should be treated as unverified regardless of how professional the document itself looks.

What buyers, renters and builders are actually running into

Two separate problems surface repeatedly in community discussion around energy ratings, and they are easy to conflate but need different responses. The first is outright misrepresentation of what a rating means: peer-reviewed research examining volume home builders' marketing under Australian Consumer Law found six-star logos designed in a way likely to be read as "the best possible rating" rather than what it actually was — the regulatory minimum that applied to every new home at the time (The Conversation, spruiking the stars). Now that the NCC 2022 minimum has moved to 7 stars in most jurisdictions, a certificate or display-home sign still quoting an old 6-star benchmark as if it were exceptional is the same pattern resurfacing under a new number.

The second, more practical complaint is confusion between rating systems. The ACT runs its own scale for existing dwellings — the ACT House Energy Rating Scheme (ACTHERS) — which ranks a property from 0 to 6, a different numeric scale to the national NatHERS 0-to-10 scheme used for new builds and renovations. A government-commissioned review of the ACT scheme itself flagged inconsistencies in how ratings were produced and understood by the market (Planning ACT, review of the ACT Energy Efficiency Rating Disclosure Scheme). For a buyer comparing a Canberra listing quoting an ACTHERS number against a Sydney listing quoting a NatHERS star rating, that scale mismatch alone is enough to make a mediocre rating look better than it is — before fraud even enters the picture.

Australia's patchwork of disclosure rules

Unlike the UK's single MEES mandate, disclosure obligations vary sharply by jurisdiction, which changes both the incentive to fake a rating and where a buyer or agent should go to check one.

Australia's federal, state and territory energy ministers released a national Home Energy Ratings Disclosure Framework in 2024 specifically to give states a common template for introducing point-of-sale or point-of-lease disclosure, rather than each jurisdiction inventing its own scheme from scratch (energy.gov.au, Home Energy Ratings Disclosure Framework). Until every state adopts it, a rating that would face public scrutiny in Canberra at the point of sale may never be checked at all in a state where disclosure is still voluntary.

How to verify a NatHERS certificate before you rely on it

Five checks catch most fraudulent or unreliable ratings, starting with the NatHERS Assessor Register lookup — the single fastest way to confirm the person named on the certificate is currently accredited.

Where document verification fits

Manual review of NatHERS certificates, Development Application paperwork, and title documents does not scale well against fraud that is designed to look routine. Industry-wide, the ACFE's 2024 Report to the Nations found that manual detection methods alone catch only 37% of fraud cases, with an average discovery delay of 87 days from the point the fraud began (ACFE 2024 Report to the Nations) — long enough for a manipulated rating to have already cleared a council approval or a lease sign-off.

CheckFile's review of NatHERS certificates and supporting documentation draws on multi-layer analysis — structural, metadata, and cross-document consistency checks — to flag records whose data does not hold together, such as a climate zone that doesn't match the property address or a software tool version inconsistent with the stated assessment date. For certificates that appear to have been digitally recreated rather than genuinely issued, an additional layer of AI-generation signals, deployed according to client configuration, complements these structural checks for certificates suspected of being synthetically produced or digitally altered — as a complement to your existing controls, not a replacement for the Assessor Register lookup described above. This approach is described in more detail on CheckFile's AI deepfake detection page, alongside the sector-specific tooling on the real estate solutions page.

NatHERS certificates rarely arrive in isolation on a property file. Agents and conveyancers checking a rating are frequently also verifying grant paperwork tied to energy improvement works claimed against a rating, or title documents changing hands in the same transaction. CheckFile's broader approach to sector document risk is set out on the industry verification guide, and platform security and data handling are covered on the security page.

Frequently Asked Questions

How do I check whether a NatHERS assessor is legitimately accredited?

Search the assessor's name or accreditation number on the public NatHERS Assessor Register at nathers.gov.au. If the person isn't listed, or their accreditation shows as suspended or revoked, treat the certificate as unverified and raise it with the relevant Assessor Accrediting Organisation before relying on it.

Why does a NatHERS rating in Canberra look different from one in Sydney?

The ACT uses its own scheme for existing dwellings, the ACT House Energy Rating Scheme, which scores a property from 0 to 6. The national NatHERS scheme used for new builds and renovations scores from 0 to 10. The two numbers are not directly comparable, and confusing them can make a mediocre rating look stronger than it is.

Is mandatory energy rating disclosure required when I sell or lease a home outside the ACT?

Not yet as a blanket rule. The ACT has required disclosure at sale since 1999. NSW is running a voluntary disclosure trial with mandatory disclosure under consideration from mid-2026 depending on the trial's results, and Victoria has confirmed it is considering a similar mandatory scheme. Elsewhere, NatHERS applies to new-build compliance but not necessarily to point-of-sale disclosure.

What happens to a builder or assessor caught misrepresenting a star rating?

An assessor found to have manipulated inputs or issued a rating without a genuine assessment can have their accreditation suspended or revoked by their AAO following a quality-assurance audit or complaint investigation. Builders whose marketing misrepresents what a rating means can also fall within the scope of the Australian Consumer Law's prohibition on false or misleading representations, an area the ACCC has flagged as an enforcement priority for environmental and energy claims.

Does a 7-star NatHERS rating replace a Whole-of-Home energy assessment under NCC 2022?

No. NCC 2022 introduced the 7-star thermal performance minimum alongside a separate Whole-of-Home energy budget covering appliances, hot water, and on-site energy generation. A certificate showing only the star rating without Whole-of-Home data is incomplete for full NCC 2022 compliance purposes in jurisdictions that have adopted both requirements.

Ready to add a document verification layer to your property transaction checklist? See how CheckFile approaches structural and AI-generated document detection for real estate teams, or get started to talk through pricing on the plans page.