8 STAR vs 6 STAR

So obviously an 8 star energy efficient house will perform better than a 6 star one. But by how much?  I’ve recently been involved in some consulting work for a housing design competition in the Pilbara where we attempted to illustrate exactly that.

We settled on two graphs. The first one shows the difference in energy required to cool a 6 star house compared to an 8 star one (remember, it’s in the Pilbara, the north-west of Australia, where virtually no heating is required throughout the year). It’s takes about 40% less energy to cool the 8 star home.

The second graph shows some extrapolated air-conditioning operating costs between the 8 star and the 6 star dwelling.

Indicative Airconditioning costs per anuum: 8 star vs 6 star



  • Aurelio Carbone

    October 24, 2019 at 3:41 am Reply

    Given that cooling is a matter of resistance and retention, what is the cooling temperature sought in an 8 star dwelling and over what time period of the day?

    • Sid Thoo

      March 5, 2020 at 3:58 am Reply

      Hi Aurelio,

      Thanks for your comments, and apologies for the delayed reply. Sadly, most comments I receive are spam, so I stopped checking them for a while!

      If you are interested in knowing the thermostat settings used in NatHERS rating software, have a look at this document here:


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