A NatHERS Star Rating and Whole of Home calculation for every dwelling in your Class 2 development.
Class 2 developments are assessed dwelling by dwelling, but they are not independent of one another. Party walls, shared floors and the shading each building casts on its neighbour all affect the result.
Modelling the dwellings together rather than in isolation usually produces a better outcome for the development as a whole. A specification that works across every dwelling is simpler to build and to price than a different glazing schedule for each.
Where one dwelling proves difficult, the cause is often the orientation or overshadowing set by the site layout. Raising it while the siting is still open is considerably cheaper than solving it later through the specification.
Energy efficiency compliance for Class 2 developments under NCC 2025, via the NatHERS pathway (H6P1) and Whole of Home (H6P2), with separate certificates issued for each dwelling.
Each dwelling is modelled individually in FirstRate5 and adjustments made to ensure that apartments across the development reach a minimum average of 7 stars, with no individual dwelling below 6 stars as per the NCC 2025 (note that this requirement may vary depending on the state your project is located in). Whole of Home scores to reach a minimum of 50 for each dwelling.
Often required by councils to support a planning application, with finalised certificates issued for building permit.
Stage 1 — Project Initiation. Studio Bun reviews your drawings, specifications and brief, identifies the NCC 2025 requirements that apply to the project, and issues a proposed compliance pathway together with a fixed fee covering the full process.
Stage 2 — Preliminary Assessment & Design Advice. The proposed design is modelled, adjusted and assessed. We issue a Preliminary Assessment Report setting out what is required for compliance. This stage identifies the key challenges to the project and the improvements available, whether to exceed compliance or to reduce the cost of meeting it.
Stage 3 — Design Iteration & Optimisation. Between the preliminary and final reports we allow two rounds of minor changes to the design, and a meeting to review the recommendations. From here we can focus on cost efficiency or on performance, as the project requires.
Stage 4 — Certification & Final Reporting. Once the final specification and design are documented, we run the final model for each dwelling, confirm the results and issue a NatHERS and Whole of Home certificate per dwelling. Changes after certificate issue are charged at an additional rate, depending on the size and scope of the change and the number of dwellings affected.
Thermal modelling of every dwelling in the development in FirstRate5 (similar dwellings may be grouped)
A Whole of Home calculation for each dwelling (similar dwellings may be grouped)
Assessment of shared walls, shared floors and inter-dwelling shading
A preliminary report covering the development, identifying the dwellings that drive the specification
A common specification strategy across dwelling types where achievable
Pathways for cost reduction or optimisation where applicable
Two rounds of minor changes between preliminary report and finalisation
A final assessment report
NatHERS and Whole of Home certificates for each dwelling
A few items sit outside this scope and can be quoted separately:
Class 2 apartment building common areas with centralised services, which may require VURB or JV3 assessments
Single dwellings (see NatHERS for single dwellings)
Minor design changes beyond two rounds
Blower door and air permeability testing
Acoustic, daylight or mechanical assessments
BESS reports (if required, available as its own service)
Sustainable design assessments (if required, available as its own service)
Sustainability management plans (if required, available as its own service)
Stormwater management plan (available as its own service)
This service assumes Class 2 dwellings under NCC 2025, with PDF drawings sufficiently complete for modelling.
Studio Bun offers fixed sum packages for multi dwelling NatHERS assessments, priced on the number of dwellings, the number of distinct dwelling types and the complexity of the development. Repeated dwelling types are more economical to assess than a development where every dwelling differs. Packaging with BESS assessments, sustainable design assessments or sustainability management plans (if required) is also available.
Contact us for a quote.
How is an apartment building assessed against NatHERS?
Differently from houses and townhouses. A Class 2 building is assessed as a whole: the sole-occupancy units must reach an average of 7 stars, with no individual apartment falling below 6 stars. That averaging is the key difference. An apartment that struggles on orientation can be balanced against a better performing one, which is not possible on a Class 1 site where every dwelling has to reach 7 stars in its own right.
Does every apartment still need its own certificate?
Yes. Each sole-occupancy unit is modelled individually and receives its own NatHERS and Whole of Home certificate, even though the star rating is assessed as a building average.
What is the Whole of Home requirement for apartments?
A minimum score of 50 for each apartment, rather than the 60 that applies to houses and townhouses. The lower target reflects how little roof area and appliance freedom an individual apartment has, with on-site solar limited and hot water and space conditioning often decided building wide. Unlike the star rating, Whole of Home is not averaged. Every unit has to reach 50 on its own.
What if the building has centralised hot water or heating?
This is the part of apartment assessment still in transition. NatHERS Whole of Home has not historically accommodated centrally serviced buildings, which is why those projects have gone down the JV3 or NABERS route instead. An Apartment Centralised Services Method has been developed to apportion shared plant energy to each unit. We will confirm which pathway applies to your building before any fee is agreed, because it materially changes the scope.
What about the common areas?
Corridors, lobbies, car parks, plant rooms and other shared parts of a Class 2 building are not covered by NatHERS. They fall under NCC Volume One Section J and are assessed separately. That work is available as its own service.
When should we engage on an apartment project?
While the building envelope is still being resolved. Because the rating is a building average, the apartments that drag the result are usually determined by orientation, floor plate depth and overshadowing, all of which are fixed by the massing. Once the envelope is set, the only levers left are glazing and insulation specification, which is the expensive way to reach the same number.
Send through your drawings and dwelling schedule for a fixed-fee quote.
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