Mechanisms of Change
Published on January 14, 2021
Regulation has been the main driver of change with mandatory requirements established. These have commonly been based on prescriptive codes based on U-values for individual construction elements.
In Australia, the Nationwide House Energy Rating Scheme (NatHERS) supports the efforts of the Australian Governments to reduce the energy and greenhouse gas impact of residential buildings. NatHERS encourages energy efficient building design and construction by providing a reliable way to estimate and rank the potential thermal performance of residential buildings in Australia.
Heating and cooling accounts for the majority of the average Australian household’s energy use, but efficient building design can reduce the reliance on artificial temperature controls. To determine how efficient the design of a home is, it is given a star rating between zero and ten stars. Homeowners can make use of these ratings to determine modifications to existing houses or in planning the designs for a new house.
The star rating is calculated using software accredited for this purpose under NatHERS. The software simulates expected conditions based on climate zones and other known factors about the location, occupancy and dimensions of the house. Allowances are made for different sized houses and different climates to ensure a fair comparison of buildings and consistent ratings across Australia. While the software can be used by anyone, only an assessor who has received NatHERS accreditation from a relevant organisation can provide a credible rating.
NatHERS tools provide one method of demonstrating compliance with the minimum energy efficiency standards for new residential buildings outlined under the National Construction Code (formerly the Building Code of Australia). Additionally, NatHERS software is a powerful tool for optimising energy efficient house designs for Australian climates. It also highlights the weakest link in the building envelope.
The Australian Window Energy Rating Scheme (WERS) audits and provides the window ratings used in building design and are available on the WERS website.