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The 7-star NatHERS rule and what it means for a modular or prefab home
| Introduced by | NCC 2022 — the residential energy efficiency provisions[1] |
|---|---|
| Minimum building fabric rating | 7 stars NatHERS (out of 10), up from 6 stars[1] |
| New requirement | A whole-of-home energy budget covering heating/cooling, hot water, lighting and pool or spa pumps, which rooftop solar can offset[1] |
| NSW | Mandatory from 1 October 2023[2] |
| VIC / QLD | Mandatory from 1 May 2024[2] |
| SA | Mandatory from 1 October 2024[2] |
| ACT | Mandatory from 15 January 2024, delayed from an original October 2023 start[3] |
| WA | Voluntary from 1 October 2023, mandatory from 1 May 2025[2] |
| NT | Voluntary from 1 October 2023; no mandatory date set as of the source below[2] |
| TAS | Has not adopted the NCC 2022 energy efficiency provisions; NCC 2022 applies until 1 May 2027, when NCC 2025 is to be adopted[2][4] |
Since NCC 2022, a new home in most of Australia has needed a minimum 7-star NatHERS rating for its building fabric, up from the previous 6-star minimum, plus a new "whole-of-home" energy budget covering fixed appliances[1]. The rule applies to any new dwelling regardless of construction method — but the rollout has not happened on one national date, and a modular home's advertised star rating is not automatically the rating it will get on your block.
What actually changed §
The building fabric requirement — insulation, glazing, sealing — moved from a 6-star to a 7-star NatHERS minimum, which Sustainability Victoria describes as cutting heating and cooling energy demand by 20–25% compared with a 6-star home in most areas[1]. Separately, NCC 2022 introduced a whole-of-home energy budget: a cap on the annual energy used for heating and cooling, hot water, lighting, and any pool or spa pump, which can be offset by installing rooftop solar[1].
Why this matters more for a modular or prefab buyer §
A NatHERS rating is not a fixed property of a floor plan — it is calculated for climate zone and adjusted for the specific block's orientation[1]. A poorly oriented block needs more insulation and better glazing to reach the same 7-star outcome than a well-oriented one does[1]. That matters specifically for modular and prefab buyers because a builder's advertised "7-star" display home or standard design reflects an assessment done for a specific orientation and climate zone — not necessarily yours. Before signing, it's worth asking the builder for a NatHERS certificate calculated for your actual block, not the display model's rating, since a differently oriented site may need upgraded glazing or insulation that isn't in the base price.
Where each state and territory stands (as of September 2026) §
The 7-star provisions did not commence on the same date everywhere, and Tasmania has not adopted them at all yet.
| State/territory | Status | Source |
|---|---|---|
| NSW | Mandatory from 1 October 2023 | [2] |
| VIC | Mandatory from 1 May 2024 | [2] |
| QLD | Mandatory from 1 May 2024 | [2] |
| SA | Mandatory from 1 October 2024 | [2] |
| ACT | Mandatory from 15 January 2024 (delayed from October 2023) | [3] |
| WA | Voluntary 1 October 2023 – 30 April 2025; mandatory from 1 May 2025 | [2] |
| NT | Voluntary from 1 October 2023; no mandatory date set | [2] |
| TAS | Not adopted; NCC 2022 applies until 1 May 2027, when NCC 2025 is to be adopted | [2][4] |
Does NCC 2025 change any of this? §
For almost everyone, no — and that is the point worth understanding, because "a new building code is coming" is easy to misread as "the energy requirements are about to move again."
NCC 2025 does change other parts of the housing rules, and each state is adopting it on a different date — see NCC 2025 and new homes.
At their meeting on 22 October 2025, Building Ministers agreed the content and timing of NCC 2025. They decided there would be no further residential changes in that edition beyond essential safety and quality items: voluntary embodied carbon provisions would be issued as ABCB guidance rather than code, and the proposed EV charging provisions and residential energy efficiency changes would not be introduced. The communiqué states that this approach maintains the energy efficiency standards adopted in NCC 2022, including 7-star[5].
Ministers went further and agreed to pause any further residential changes to the NCC, other than essential quality and safety measures, until mid-2029[5]. NCC 2025 was to be published by 1 February 2026, with states and territories able to consider adoption from 1 May 2026 — but adoption is a matter for each jurisdiction[5].
The practical consequence for a buyer: whether your state adopts NCC 2025 early, late or on a transition arrangement does not change your 7-star position, because NCC 2025 does not alter the residential energy provisions. The 7-star requirement is a settled standard for the next few years, not a rising target you need to build ahead of.
Tasmania is the exception, and only because it never adopted the NCC 2022 energy provisions in the first place — so the 7-star question there rides on NCC 2025 rather than NCC 2022. The sequence has been unusual. NCC 2025 commenced in Tasmania on 1 May 2026, then the Building Amendment Act 2026 took effect on 5 June 2026 and reinstated NCC 2022 as the applicable code. NCC 2022 now applies in Tasmania until 1 May 2027, when NCC 2025 is to be adopted[4].
Tasmanian buyers with a design already under way should note that section 11(5) of the Building Act 2016 provides transitional exemptions in certain circumstances — including where a certificate of likely compliance was issued before the code was adopted, or where a building surveyor or permit authority certifies in writing that substantial progress had been made on the design before adoption[4]. Whether either applies to a particular project is a question for your building surveyor, not something that can be settled from a general page like this one.
What this means when you're comparing builder quotes §
Ask which NCC edition and which state's adoption date a quoted design was assessed against — a design costed before your state's mandatory date may not yet reflect the extra insulation, glazing or solar needed to comply. Ask whether the whole-of-home energy budget is met through rooftop solar included in the contract price, or whether solar is an optional extra needed to hit the budget — this affects the real comparison between a "compliant" quote and one that assumes solar is added later. And treat a builder's advertised star rating as a starting point rather than a guarantee, since the certificate that actually matters is the one calculated for your block[1].
In Tasmania there is a further question worth asking directly: whether a quote has been prepared against NCC 2022 as it currently applies, or against the requirements that will apply from 1 May 2027. A build that is quoted now but certified later may land under the later edition.
What this page does not cover §
This page covers only the residential 7-star/whole-of-home energy provisions. It does not cover NCC 2025's separate commercial and apartment building changes, the liveable housing (accessibility) provisions bundled into the same NCC 2022 update, or the NCC 2025 adoption dates of individual states, which vary but do not change the residential energy position described above. The Northern Territory's position on NCC 2025 has not been confirmed from a government source here, and Tasmania's eventual residential energy settings under NCC 2025 had not been separately confirmed at the time of writing.
Related guides §
- Modular home energy efficiency
- ABCB prefab certification scheme consultation
- Modular home cost breakdown
- Choosing a prefab builder
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References §
- Sustainability Victoria (Victorian Government) — 'Seeing 7-stars: new home energy efficiency standards explained' — describes the national NCC 2022 change from a 6-star to a 7-star minimum building fabric rating, the whole-of-home energy budget, and that a rating depends on climate zone and orientation. sustainability.vic.gov.au/energy-efficiency-and-reducing-emissions/building-or-renovating/7-star-homes-program/seeing-7-stars-new-home-energy-efficiency-standards-explained
- Nationwide House Energy Rating Scheme (NatHERS), Australian Government — 'NCC 2022 Software Transitional Arrangements' — the state and territory voluntary/mandatory adoption dates for the NCC 2022 energy efficiency provisions, including Tasmania's non-adoption. nathers.gov.au/software/transitional-arrangements
- ACT Government (Chief Minister, Treasury and Economic Development Directorate) — Media release confirming the ACT's energy efficiency and liveable housing requirements took effect on 15 January 2024, delayed from an original October 2023 date. cmtedd.act.gov.au/open_government/inform/act_government_media_releases/vassarotti/2023/2024-to-bring-energy-efficiency-and-liveable-housing-requirements-for-new-act-buildings
- Consumer, Building and Occupational Services (Tasmanian Department of Justice) — National Construction Code page, updated 5 June 2026 — records that NCC 2025 commenced in Tasmania on 1 May 2026, that the Building Amendment Act 2026 reinstated NCC 2022 from 5 June 2026, that NCC 2022 applies until 1 May 2027, and the transitional exemptions under section 11(5) of the Building Act 2016. cbos.tas.gov.au/topics/technical-regulation/building-standards/national-construction-code-ncc-2025/national-construction-code-ncc-2026
- Australian Treasury — Meeting communiqué, Building Ministers' Meeting, 22 October 2025 — the agreed content and timing of NCC 2025, the decision that residential energy efficiency and EV charging changes would not be introduced, and the pause on further residential NCC changes until mid-2029. treasury.gov.au/media-release/meeting-communique-building-ministers-meeting-october-2025
Figures are as published by the sources above at their respective dates and are paraphrased summaries, not verbatim reproductions. Verify current pricing and rules directly with builders, lenders and planning authorities.