The following summarizes the key energy efficiency comparisons between a 7 star rating and a 6 star rating.
- Demands 8-20% less energy for combined heating and cooling
For instance, in Melbourne, the maximum combined energy requirement under 6 star was 120 MJ/m2 which is now dropped to 110 MJ/m2 under 7 Star. The same limits for Brisbane under 6 star and 7 star are 120 MJ/m2 and 105 MJ/m2.
- Generates 25% less greenhouse gas emissions
The climate council’s report associates an extra added star with a 25% cut in greenhouse gas emissions.
- Cuts annual energy bills by an average of $500 and provides better thermal comfort for occupants.
Annually, a 7 star house would save households between $119 to $945 on heating and cooling electricity demands (reference).
- Imposes less peak load strain on the electricity network.
If the houses are built to decrease peak demand, especially on cooling energy, the network adapts better to future increases in electricity consumption and blackouts would occur less often.