Home energy 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).
Recent changes to the NCC include the introduction of a new minimum 7-star rating or equivalent, as well as an annual energy use budget for the entire home, including major fixed appliances, solar and batteries.
Assessing a home’s energy performance
Energy assessors use NatHERS computer modelling tools to predict the amount of heating and cooling your apartment or house will need to stay comfortable year-round. This is based on the home’s design, materials and construction, including the:
- layout of the home and its orientation
- roof, walls, windows and floor, construction methods and materials
- shading from the sun's path and how well it takes advantage of local breezes.
The findings are converted to a rating between 0 and 10 stars, which is specific to your home.
NatHERS assessments now also include an indication of your expected annual energy use. This new ‘whole of home’ rating predicts the energy your new home’s major fixed appliances will use, as well as any energy generated or stored onsite from solar panels and batteries.
What the stars mean
Homes are given a star rating between 0 and 10. A higher star rating means the home is more comfortable to live in and is cheaper to run. Lower star ratings mean a home is more costly to keep comfortable.
Below is a general guide to ratings:
- a 0-star rated home is quite uncomfortable – too hot in summer and too cold in winter. It will require a lot of energy to heat and cool.
- a home reaching a 7-star rating will need some mechanical heating and cooling to keep it comfortable to live in.
- a 10-star home is very energy efficient. It will remain comfortable year-round, with limited, or no mechanical cooling or heating.
The key to achieving a comfortable, high-performing home is to design for your local climate. See examples of high star-rated homes in different locations on the Your Home website.
Getting an assessment
Energy assessors use house plans and construction details to enter data into NatHERS Accredited Software to produce a star rating. The rating is based on scientific research by the CSIRO.
Good design is key to achieving a high star rating, so speak to an accredited assessor early in the design phase. They can advise on important factors such as house orientation, building materials, suitable appliances and construction, which may not be possible to change later.
Find an accredited NatHERS assessor by:
- searching the Accredited Assessor Directory on the Australian Building Sustainability Association website
- reviewing the Design Matters National database — select Thermal Performance Assessor and enter your postcode
- completing 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.