Specification 42 (NCC 2022)
Specification 42 of NCC 2022 Volume Two is the NatHERS compliance pathway: 7-star minimum thermal rating plus a Whole-of-Home energy budget ≥ 60.
Ask Chalkline about this →Specification 42 is the schedule in NCC 2022 Volume Two (the residential volume of the National Construction Code) titled “House energy rating software”. It is the consolidated home of the NatHERS-pathway energy efficiency requirements for Class 1 and Class 10 buildings (verified 2026-05-15 against ncc.abcb.gov.au).
Specification 42 does two things on every new home that goes down the NatHERS compliance pathway (the alternative is the DTS Elemental Provisions in Part 13.2):
- Sets the thermal rating minimum. Clause S42C2 requires a Nationwide House Energy Rating Scheme rating of at least 7 stars (up from 6 stars under NCC 2019), with heating and cooling load caps that vary by NCC climate zone. Allowances are available in climate zones 1 and 2 for outdoor living area and ceiling fans.
- Sets the Whole-of-Home energy budget. Clause S42C3 requires a Whole-of-Home score of at least 60 using an accredited NatHERS software tool. The Whole-of-Home assessment includes major fixed appliances (hot water, cooktop, fixed cooling) and on-site energy generation and storage (PV, batteries) in the energy accounting.
Builders see Specification 42 every time a NatHERS report is the energy efficiency compliance document on a Class 1a project. The report’s “compliance summary” page is essentially a Specification 42 checklist.
Also known as: NCC 2022 Spec 42; House Energy Rating Software specification.
Category: Compliance.
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Last updated: 2026-05-15. Verified: 2026-05-15. Quarterly review for currency.