What Is a NatHERS Assessment?
A NatHERS assessment evaluates how much energy a home needs for heating and cooling to maintain comfortable temperatures year-round. Using approved software tools such as FirstRate5, BERS Pro, or AccuRate, an accredited assessor models your home’s thermal performance based on its design, construction materials, orientation, glazing, insulation, and local climate zone.
The result is a star rating between 0 and 10 stars. A 10-star home needs virtually no artificial heating or cooling, while a 0-star home has no thermal performance. Under the NCC 2022 changes, the minimum requirement for new residential buildings is now 7 stars in most states and territories.
Who Needs a NatHERS Assessment?
A NatHERS assessment is required for a range of residential building projects across Australia. If you fall into any of the following categories, you will need to engage an accredited assessor:
- New home builds — All new Class 1 (houses) and Class 2 (apartments) buildings must meet the minimum star rating before a building permit is issued.
- Major renovations — Extensions and alterations that increase the conditioned floor area or significantly modify the building envelope may trigger NatHERS compliance.
- Property sales in the ACT — The ACT requires an Energy Efficiency Rating (EER) based on NatHERS for all residential property sales.
- Voluntary upgrades — Homeowners seeking to understand their home’s thermal performance or plan energy-saving improvements.
How the NatHERS Assessment Process Works
When you request a quote through ESD Consultants, we connect you with an accredited NatHERS assessor in your area. Here is what to expect:
- Submit your project details — Provide your architectural plans, site plan with orientation, and construction specifications. Your assessor will confirm exactly what is needed.
- Thermal modelling and assessment — The assessor models your home in NatHERS-approved software, accounting for your specific climate zone, building materials, glazing, insulation, shading, and ventilation.
- Report and certificate delivery — You receive a NatHERS certificate showing your star rating, along with recommendations if the design does not yet meet the minimum requirement. Most assessments are delivered within 3–5 business days.
NatHERS Assessment Costs
The cost of a NatHERS assessment depends on the size and complexity of your dwelling, your location, and how quickly you need the report. Typical price ranges are:
- Standard house (up to 250m²): $400–$600
- Large or complex home (250m²+): $600–$800
- Multi-storey or custom design: $800–$1,500
- Apartment (single unit): $300–$500
- Urgent turnaround (1–2 days): Add 30–50%
For a detailed breakdown, see our energy rating cost guide.
State-by-State NatHERS Requirements
While NatHERS is a national scheme, each state and territory has its own implementation rules:
- Victoria — 7-star minimum under NCC 2022. Many councils require additional sustainability reporting.
- NSW — NatHERS applies alongside the BASIX Certificate, which sets separate energy and water targets.
- Queensland — 7-star minimum with climate-specific adjustments for tropical zones.
- South Australia — 7-star minimum with additional focus on summer cooling loads.
- Western Australia — 7-star minimum under NCC 2022 with transitional provisions.
- ACT — 7-star minimum for new builds plus mandatory disclosure via EER for sales.
- Tasmania — 7-star minimum under NCC 2022.
- Northern Territory — 7-star minimum with emphasis on cooling performance.
Tips to Achieve a Higher Star Rating
If your initial assessment falls short of the required star rating, your assessor can recommend cost-effective improvements. Common strategies include:
- Improving wall and ceiling insulation R-values
- Upgrading to double-glazed or low-E windows
- Optimising window size and orientation for solar gain
- Adding external shading devices such as eaves or pergolas
- Sealing air gaps and improving draught-proofing
- Choosing lighter-coloured roofing materials in hot climates
Use our Energy Rating Calculator for an initial estimate of your home’s performance before engaging an assessor.
Frequently Asked Questions
What is a NatHERS assessment?
A NatHERS (Nationwide House Energy Rating Scheme) assessment is a star rating system that measures the energy efficiency of a residential building's thermal envelope. Ratings range from 0 to 10 stars, with higher ratings indicating less energy needed for heating and cooling.
How much does a NatHERS assessment cost?
A NatHERS assessment for a standard residential dwelling typically costs between $400 and $800. Larger or more complex homes, including multi-storey designs or homes with multiple living zones, may cost $800 to $1,500. Costs vary by location and assessor.
How long does a NatHERS assessment take?
Most NatHERS assessments are completed within 3 to 5 business days from receipt of all required plans and documentation. Urgent turnaround within 1-2 business days is often available at an additional cost.
What documents do I need for a NatHERS assessment?
You will need architectural floor plans, elevations, a site plan showing orientation, window and door schedules, and specifications for insulation, glazing, and wall construction. Your assessor will advise on any additional documentation required.
Is a NatHERS assessment mandatory?
Yes. Under the National Construction Code (NCC), all new residential buildings and major renovations must achieve a minimum NatHERS rating (currently 7 stars under NCC 2022) or demonstrate equivalent compliance via an alternative pathway.