I thought 5 stars was the highest rating that could be achieved. What is the meaning of 6 and 7 star ratings?
When the NatHERS Scheme began, 99 per cent of Australian houses fell below the 5 star standard. A 5 star scale seemed enough to cover the vast bulk of housing designs at the time. As energy efficiency levels have improved and better software is available to measure higher performance, the full 10 star scale (equivalent to zero conditioning energy) has been brought into play for the rating scheme.
