Home energy star ratings
Nationwide House Energy Rating Scheme (NatHERS) assessments are the most common way to meet the minimum energy efficiency requirements of the National Construction Code (NCC).
Energy assessors use the NatHERS rating tools to predict the amount of heating and cooling your apartment or house will need to stay comfortable all year round. The findings are converted to a star rating between 0 and 10 stars.
What the stars mean
Homes with a higher star rating are considered more thermally comfortable and cheaper to run than homes with a lower star rating.
- A 0-star rating means the building shell does practically nothing to reduce the discomfort of hot or cold weather.
- A 6-star rating is the minimum standard in most states and territories. It indicates good, but not outstanding, thermal performance.
- A 10-star rated home may not need any artificial cooling or heating to keep you comfortable.
The full range of stars from 0 to 10 is called a star band. Star bands are based on the amount of energy predicted to be used for homes in different locations.
The key to achieving a comfortable, high-performing home is to design for your climate. See examples of high star-rated homes on the Your Home website.
How ratings are determined
The calculations in the NatHERS rating tools are based on scientific research by the CSIRO.
Your home’s rating depends on how well these factors suit the local climate:
- layout of the home and orientation
- roof, walls, windows and floor construction methods and materials
- shading to the sun's path and how well your home takes advantage of local breezes
What’s not rated
Hot water systems, lights and household appliances aren’t taken into account in NatHERS ratings because they’re usually replaced several times in the building’s lifetime.
Energy rating assessments
Assessors use your home’s plans and construction details to enter data into NatHERS Accredited Software to produce a star rating.
Consider engaging an assessor early in the design phase. Your assessor will give you advice on important factors such as house orientation and construction which may not be possible to change closer to the building approvals stage. Good design is key to achieving a high star rating.
You may engage a NatHERS Accredited Assessor, or non-accredited assessor, to conduct an energy rating assessment for your home. You should check your local requirements as Australian states and territories have different requirements as to whether they accept house energy rating certificates from non-accredited assessors to meet compliance for building approvals.
Using a NatHERS Accredited Assessor can help you to ensure you are getting the best advice. Accredited assessors must:
- follow an Assessor Code of Practice that requires strong standards of professionalism and consumer safeguards
- undergo independent quality assurance reviews
- receive ongoing professional development to help them to stay up to date with industry best practice
Find a NatHERS Accredited Assessor
There are three associations that accredit NatHERS assessors:
- Search the Accredited Assessor Directory on the Australian Building Sustainability Association website.
- Search the Design Matters National database: select Thermal Performance Assessor and enter your postcode.
- Complete the House Energy Rater referral form on the House Energy Raters Association website.
- Find the best design solutions for your climate zone on the Your Home website.
- Free house designs with high star ratings are available on the Your Home website.
- Get practical advice on choosing and using appliances efficiently on Energy.gov.au.