Home Thermal Performance Estimator

Answer simple questions about your home and get an indicative estimate of how it would sit on the NatHERS 0–10 star scale, benchmarked against the official 2022 NatHERS star bands for your climate zone.

Indicative estimate only Uses official NatHERS star bands & climate zone postcodes

This is not an official NatHERS rating. Official star ratings can only be produced by an accredited assessor using NatHERS-accredited software (such as AccuRate, FirstRate5, HERO or BERS Pro) which runs CSIRO's Chenath engine over 8,760 hours of local climate data (Nationwide House Energy Rating Scheme [NatHERS], 2025). This tool gives you an educational estimate of where your home is likely to sit, and explains what drives the result. To find an accredited assessor, see nathers.gov.au.

Step 1 — Where is the home?

Postcode

NatHERS climate zone (auto)

Australia is divided into 69 NatHERS climate zones (plus Christmas Island), each with its own hourly weather file and its own star-band benchmarks — the same design earns different stars in different climates (NatHERS, 2025). The lookup uses the official September 2025 postcode list. Some postcodes span more than one zone (for example where altitude changes the climate); this tool uses the primary zone for your postcode.

Step 2 — About the home

Step 3 — Your indicative result

Method, assumptions and limitations

What the tool does: it scores your answers against the passive-design factors that NatHERS modelling is most sensitive to — orientation, insulation, glazing, shading, air sealing, thermal mass, ventilation and layout (NatHERS, 2025; Commonwealth of Australia, 2024). The score is mapped to the 0–10 star scale, and the corresponding maximum heating-plus-cooling load for your climate zone is read from the official 2022 NatHERS star band table (NatHERS, 2023).
The scoring rubric and its weightings are this tool's own methodology. They are informed by Australian Government passive design guidance but are not a NatHERS calculation. A real assessment simulates your actual floor plan hour by hour and routinely differs from simple scoring by a star or more in either direction.
Star bands: official values from the 2022 NatHERS Star Bands (used under NCC 2022). Values are maximum area-adjusted annual heating + cooling loads (MJ/m² per year) — the lower the load, the more stars.
Not modelled: the Area Correction Factor (small homes are treated more leniently and large homes more strictly in real ratings), the separate ABCB heating and cooling load caps that apply in addition to 7 stars under NCC 2022 (Australian Building Codes Board [ABCB], 2022), secondary climate zones within a postcode, and the Whole of Home appliance rating.
NCC 2022 context: most new homes must now achieve at least 7 stars plus a Whole of Home energy budget; timing varied by state (e.g. Victoria and Queensland from 1 May 2024, South Australia from 1 October 2024; NSW applies equivalent standards through BASIX) (ABCB, 2022; NatHERS, 2025).

References (APA 7th edition)

Australian Building Codes Board. (2022). Standard for NatHERS heating and cooling load limits. https://www.abcb.gov.au/resource/standard/nathers-heating-and-cooling-load-limits

Commonwealth of Australia. (2024). Your Home: Australia's guide to environmentally sustainable homes — Passive design. https://www.yourhome.gov.au/passive-design

CSIRO. (2026). How NatHERS star bands were created — and how they've evolved. Australian Housing Data. https://ahd.csiro.au/how-nathers-star-bands-were-created/

Nationwide House Energy Rating Scheme. (2023). 2022 NatHERS star bands [Data set]. Australian Government. https://www.homeenergyrating.gov.au/sites/default/files/2023-01/2022%20NatHERS%20Starbands.xlsx

Nationwide House Energy Rating Scheme. (2025). NatHERS climate zones — postcode list (September 2025) [Data set]. Australian Government. https://www.homeenergyrating.gov.au/industry-professionals/assessors/assessor-resources-toolkit/nathers-climate-zone-postcodes

Nationwide House Energy Rating Scheme. (2025). Home Energy Ratings. Australian Government. https://www.homeenergyrating.gov.au/