In 2006, the Building Code of Australia set a new residential building energy efficiency standard of 5 stars, as rated by software tools accredited under the Nationwide House Energy Rating Scheme (NatHERS). The Regulation Impact Statement (RIS) on the 5-star standard analysed its likely impact on the energy efficiency of new houses relative to the previous standard finding that the new standard would reduce heating and cooling energy costs, as well as greenhouse gas emissions.
In 2012, to assess whether the new standard was achieving its goals, the Australian Government asked CSIRO to:
- find out whether the 5-star standards have actually reduced heating and cooling energy use of houses compared with those built to the earlier 3.5 to 4-star standard; and
- determine the actual benefits and costs of meeting the 5-star standard
To undertake this task, CSIRO studied 414 houses in the principal centres of population of three BCA climate zones over a winter and summer period.