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House energy ratings

In Australia, a house energy rating is necessary to gain building approval for a new home or an addition. Minimum star ratings vary between states.

House energy rating through the Nationwide House Energy Rating Scheme (NatHERS) uses computer simulations to assess the potential thermal comfort of Australian homes on a scale of zero to 10 stars. The more stars, the less likely the occupants need cooling or heating to stay comfortable.

What is rated?

A dwelling can be rated before or after it is built. The rating depends on:

  • the layout of the home
  • the construction of its roof, walls, windows and floor
  • the orientation of windows and shading to the sun’s path and local breezes
  • how well these suit the local climate zone

Hot water systems, lights or household appliances are not part of the rating as those fittings are usually replaced several times during the life of the building.

What the stars mean

A rating of no stars means the building shell does practically nothing to reduce the discomfort of hot or cold weather.

A 5 star rating indicates good, but not outstanding, thermal performance.

Occupants of a 10 star home are unlikely to need any artificial cooling or heating.

Houses built in 1990 averaged about 1 star on the NatHERS scale. Before the introduction of national energy efficiency regulations for houses in 2003, less than one per cent of Australian houses achieved 5 stars.

Simulation Software

NatHERS regulatory framework provides legal and technical guidelines for computer thermal simulation packages which calculate how heat enters and leaves the residential spaces of a dwelling based on the standardised building material thermal properties.

EnvironArc uses a range of NatHERS accredited thermal simulation software packages.

NatHERS Assessors

Currently the only organization which is accredited by NatHERS to provide training and certification services for NatHERS is Association of Building Sustainability Assessors or ABSA. Our assessors are ABSA Accredited.

Get a Quote

To find out more, please phone 1300 738 611 or email environarc@environarc.com.au