The Nationwide Home Energy Rating Scheme (NatHERS)

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Nationwide House Energy Rating Scheme website

The Nationwide Home Energy Rating Scheme (NatHERS) sets national standards for software used to rate the thermal performance capabilities of Australian homes.  Homes are given a rating estimating the potential heating and cooling needs for the home. This allows fair comparison between different residential buildings.  

The NatHERS scheme:

  • Accredits software tools which measure the thermal potential of homes.
  • Sets standards for professionals offering NatHERS ratings.
  • Can be used to inform improvements to home design.
  • Provides one option to demonstrate compliance with the minimum energy efficiency standards for new buildings outlined in the Building Code of Australia.

The NatHERS ratings are not intended to measure actual total energy use, just as car fuel efficiency ratings do not predict actual fuel consumption.  Rather, they are a way to fairly compare the potential of different houses in relation to heating and cooling needs.

NatHERS is used mostly for new homes

All new homes (and significant renovations) built in Australia are required to meet minimum energy efficiency standards that are outlined in the Building Code of Australia (BCA). There are a number of ways that designers and builders can meet the minimum standards and increasingly, builders and designers are using a ‘software modelling approach’ to create home designs that meet the required standard. This allows designers and builders flexibility in meeting standards cost-effectively and facilitates innovation in home design.  The NatHERS scheme accredits appropriate software used for this purpose.

How do the tools work?

NatHERS-approved tools calculate the heat energy gains and losses associated with the design of a building in a particular location and determine how much artificial heating and cooling may be required to maintain a comfortable temperature in the home.

The tools use this information to determine a 'star rating' for the home between 0 (poor performance) and 10 (requiring virtually no energy to be used for heating or cooling). The star rating provides a guide about the comparative energy performance of the home. Ratings are usually done before a home is occupied.

What about energy consumption?

Each household uses energy differently—and when a home is occupied the energy bill will reflect not only energy that is used for heating and cooling, but also the energy that is used by appliances and other equipment. These vary greatly depending upon who lives in the home and their behaviour.

A simple way to think about this is to consider three identical new homes which achieved a 6-star rating in the same suburb. If one home is vacant, the second is home to a busy single professional at work for long hours each day and the third is home to a family with small children it is likely that the energy bills for these three homes would be quite different.

Who administers the scheme?

NatHERS is overseen by a committee that includes representatives from the Commonwealth and all State and Territory governments. The Department of Climate Change and Energy Efficiency is the National Administrator of the Scheme on behalf of this committee.

The BCA is implemented through State and Territory legislation. Further information is available from each State and Territory as listed below.