6 Star Energy Rating

New homes built in Victoria need to comply with the 6 Star Energy Standard set out in the National Construction Code. This means it is compulsory for new houses to have:

6 Star energy rating for the building fabric, and
A rainwater tank for toilet flushing or a solar hot water system, and
Water efficient shower heads and tapware.

A 6 star energy efficiency rating for the building fabric applies to the roof, walls, floor and windows. It requires the house to have a high level of thermal energy performance and will therefore require lower levels of heating and cooling to be comfortable in winter and summer.

In Australia the average Energy Rating for an existing house is 2 stars. The average energy use for heating and cooling in a 2 star house is 360MJ/m2 vs 120MJ/m2 for a 6 star dwelling.

You can achieve 6 stars a variety of ways. Most likely increased insulation to roof and/or walls will be required. Improved glazing may not be necessary if other elements are good – e.g. Orientation, Insulation, and Appropriate Shading – however, many homes may require double glazing or solar improved glazing to achieve 6 stars.

Builders often refer to the 6 star energy rating in their list of inclusions. It is important to look carefully at the wording. Some say “6 Star rating to all orientations”. Others will say “6 Star rating to optimal orientation”. I think in the latter case that you can assume that there will be additional costs associated with achieving the 6 star rating. The problem here is that the builder incurs costs in having the plan and location assessed for its energy rating and will wait until you have paid a deposit before arranging an assessment.