7 star NatHERS rating in VIC: NCC 2022 adoption and whole of home

What it is

The Nationwide House Energy Rating Scheme, NatHERS, scores the thermal performance of a residential building on a scale from zero to ten stars. VIC adopted the NCC 2022 energy efficiency provisions from 1 May 2024, lifting the minimum from 6 stars to 7 stars for new houses and apartments. The change also introduced a Whole of Home rating that measures the modelled energy use of the fixed appliances and on-site renewables.

TradeLens treats the 7 star plus Whole of Home check as a permit-stage risk gate. If the rating certificate attached to a building permit application sits below the minimum the platform blocks the project from moving to the lodgement step, because submitting a non-compliant design wastes the permit fee and triggers a redraft cycle with the energy assessor.

What changed on 1 May 2024

VIC and Queensland were the last two jurisdictions to adopt the NCC 2022 energy provisions. From 1 May 2024 the new minimum requirements for Class 1 and Class 2 residential buildings in VIC are:

• A 7 star NatHERS thermal rating, calculated using accredited software
• A Whole of Home score of at least 60 (out of 100) for houses
• For apartments, an average rating of 7 stars across all dwellings in the building, with no single apartment below 6 stars, and a Whole of Home average of 50

The thermal rating measures the heating and cooling energy a home needs to stay comfortable. The Whole of Home score adds the modelled energy use of hot water, cooktop, plug load and renewables. The two scores are independent: a home can hit 7 stars on thermal and still fail Whole of Home if the appliance package is poor.

Accredited software pathways

Three pieces of software are accredited under NatHERS to produce a rating: FirstRate5, AccuRate and HERO. FirstRate5 is the most widely used in VIC because it ships with VIC-specific climate files and is the legacy tool builders and assessors are familiar with from the 6 star era.

All three tools can now produce both the thermal star rating and the Whole of Home rating in a single certificate. An accredited NatHERS assessor must run the model. A self-rated PDF carries no compliance weight.

DTS and reference building alternatives

Builders are not locked into the NatHERS pathway. NCC 2022 also offers:

• The deemed-to-satisfy elemental provisions in Volume 2 part 13.2, with minimum R-values and glazing performance specified by climate zone
• The verification using a reference building method, which compares the proposed home against a notional 7 star reference

The NatHERS pathway is the most flexible because it lets the designer trade off insulation, glazing, shading and orientation against each other. The DTS path is more rigid but simpler for project home designs that repeat the same envelope.

Transition arrangements

The transition rules matter for any builder with a job that straddled the May 2024 cut-over. Building permits applied for before 1 May 2024 could be assessed under NCC 2019 (6 star) provisions, provided the permit was issued by 30 September 2024. Variations issued after that date generally have to meet the 7 star requirement if they affect the building envelope. Stage permits issued for staged building work follow the regulation in force at the time of each stage permit, which has tripped up volume builders mid-project.

Cost and design implications

A 7 star design typically needs:

• Higher R-value wall, roof and floor insulation
• Better glazing (double glazed or high-performance single glazed with low-e coatings)
• More careful orientation and shading of west and north facing glass
• Sealed building wraps with attention to air gaps

The hot water system choice is often the biggest single Whole of Home lever. A heat pump or efficient gas hot water unit can pull the score up by ten points or more over a standard electric storage unit. PV pulls the score up the same way.

VBA enforcement

The VBA includes energy efficiency in its proactive inspection program. Common findings include insulation specified on the rating but not installed, downlights cutting through ceiling insulation without IC-rated covers, and bathroom exhaust fans venting into the ceiling space instead of outside. Each can support a directions to fix or a building order under the Building Act 1993 (Vic).

What builders should verify

Three things before lodging:

1. The rating certificate matches the latest drawing set, not an earlier revision
2. The Whole of Home appliance schedule is consistent with the contract specification (especially hot water and cooktop)
3. The assessor is accredited and the certificate carries an accreditation number

If any of those are out, the certificate will not hold up in a defects dispute through DBDRV or in a VBA audit.