7 star energy rating in SA: NatHERS and Whole of Home

When did the 7 star energy rating start in SA?

PlanSA’s page on the NCC 2022 modern homes provisions states: "The Modern Homes provisions in the National Construction Code (NCC) 2022 commence in South Australia on 1 October 2024." It describes the change as "7-star equivalent energy ratings (up from 6 stars)".

The legal instrument behind that date is Ministerial Building Standard MBS 007. In Amendment 6 (April 2026), the version quoted throughout this note, clause 2.2.4 rewrites the note to Part H6 for South Australia: "Part H6 of NCC 2022 applies in South Australia from 1 October 2024." The national note printed on the ABCB site gives a different, earlier date; clause 1.6 of MBS 007 says its modifications "must be read as if they are consolidated into the Building Code."

Clause 1.5 of MBS 007 adds: "NCC 2025 will be adopted in South Australia on 1 May 2027, with NCC 2022 (and NCC 2019 – Amendment 1 in some cases) remaining in force until 30 April 2027." This note quotes the NCC 2022 edition. Which edition and which concession apply to a particular application is decided by the relevant authority assessing it.

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What a NatHERS rating assesses

NatHERS is the Nationwide House Energy Rating Scheme. Its guidance for new homes says they "are assessed using floor plans and specifications before they are constructed", and that a Star Rating "analyses climate zone, orientation, insulation, shading, window types and building materials and air leakage to estimate how much heating or cooling your home needs". The scale runs from 0 to 10 stars.

Specification 42, clause S42C2(1), sets the threshold for the software route at 7 stars, with lower figures in paragraphs (b) and (c) that apply only to buildings in climate zones 1 or 2 with a qualifying covered outdoor living area; this note does not state the climate zone of any Adelaide address. Clause S42C2(2) adds separate heating and cooling load limits, set out in the ABCB Standard for NatHERS Heating and Cooling Load Limits. The explanatory information states that the modelled loads "must not exceed three separate load limits": the total load for the star rating, the heating load limit and the cooling load limit. A design can therefore reach the star figure and still need attention on one of the two separate limits.

Whole of Home: the second rating

Clause S42C3 of Specification 42 states: "A building must achieve a whole-of-home rating of not less than 60 using house energy rating software." It serves Performance Requirement H6P2, which limits the energy value of a building’s domestic services.

NatHERS describes the Whole of Home rating as one that "assesses the home’s overall energy use, including the home’s design and construction, combined with major fixed appliances and any onsite renewable energy generation and battery storage." Its Certificate Guide (July 2023) calls it "a separate rating to the thermal rating" that "builds on the thermal performance assessment rating", and lists the equipment covered: heating and cooling, hot water systems, lighting, pool and spa equipment, cooking and plug-in appliances, and on-site energy generation and storage. Its scale "ranges from 0 to 100, where 100 is a net zero energy value home, but ratings above 100 are possible."

Deemed-to-Satisfy elemental provisions vs NatHERS

Clause H6D2 of NCC 2022 Volume Two gives two Deemed-to-Satisfy routes. Its explanatory information names them "Option 1 Energy Rating", which applies Specification 42 using house energy rating software, and "Option 2 Elemental Provisions", which uses Section 13 of the ABCB Housing Provisions — by clause 13.1.1, building fabric, external glazing, building sealing, ceiling fans, whole-of-home energy usage and services. Under H6D2(2), the elemental route to the energy usage requirement through Parts 13.6 and 13.7 is limited to "a building with a total floor area not greater than 500 m²".

The software route does not stand entirely on its own. Clause S42C4(1), as modified for South Australia by clause 2.2.8 of MBS 007, also requires listed Housing Provisions clauses on insulation, thermal breaks, slab edge insulation and Part 13.4 building sealing. For H6P2, H6D2(2)(a) pairs the Whole of Home rating in S42C3 with S42C4(2), which requires Part 13.7 of the Housing Provisions. H6D1(2) separately allows a Performance Solution. In South Australia, SA 13.1.2(2) provides that, "for the purposes of Section 13, a sunroom or the like is deemed to be a Class 10a building and must comply with 13.2.7."

The NatHERS certificate and the plans behind it

NatHERS lists the documents an assessor asks for: construction drawings (plans, elevations, sections), construction specifications, window schedules, insulation details and fixed appliance selections. The resulting certificate carries the Star Rating and the Whole of Home rating, and NatHERS states that it "is submitted as part of the building approval process."

The Certificate Guide says the certificate "allows builders, certifiers and regulatory authorities to quickly confirm that the building has been built to the design on which the energy rating assessment is based", and includes a Certificate Check list for that purpose. A certificate from an accredited assessor carries the NatHERS logo; one from a non-accredited assessor does not.

A change after the rating — a larger window, a different glazing type, a substituted hot water system — means the house no longer matches the design the certificate describes. Whether that needs a new assessment is a question for the assessor and the building certifier.

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Does 7 star apply to extensions and renovations?

Concession (2) under clause 2.2.4 of MBS 007 provides that "an alteration and/or addition to an existing Class 1 building the subject of a development application lodged prior to 1 May 2030 may comply with P2.6.1, P2.6.2, A2.2(3), A2.4(3) (as applicable) and Part 3.12 of NCC 2019 (Amendment 1)."

Concessions (3), (4) and (6) allow listed NCC 2019 provisions or "an energy rating, including the separate heating and cooling load limits, using house energy rating software, of greater than or equal to 6 stars", in each case with H6P2 of NCC 2022. They cover houses on a small or irregular allotment where the land division application was lodged prior to 1 May 2027, or on such an allotment existing as of 1 May 2027, and houses in the Master Planned Neighbourhood Zone at Mount Barker with building consent lodged prior to 1 May 2027. Concessions (7) and (8), for some buildings manufactured off site, specify NCC 2019 provisions together with H6P2, without the 6 star option. Concession (5), for workers’ or tourist accommodation, refers to the NCC 2019 provisions alone. MBS 007 defines a small allotment as "an allotment with the primary street frontage less than or equal to 10m".

These dates are those in Amendment 6 (April 2026); MBS 007 has been amended more than once. Whether a concession applies to a given house or extension is decided by the relevant authority — the council or a private building certifier — against the version of MBS 007 in force for that application.

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