Heatwaves are Australia’s most deadly natural hazard and the principle driver of peak electricity demand in South Australia. The disproportionately high peak demand increases electricity prices, causes occasional blackouts and exacerbates energy poverty, all of which limit the use of air-conditioning. Meanwhile, the desire for more energy efficient homes may decrease their heat stress resistance. This paper challenges whether the current Australian Nationwide Energy Rating Scheme encourages heat stress resistance.
Cooling consumption, peak demand and the risk of indoor overheating were assessed for a typical single-storey home in Adelaide. Design scenarios between 6 and 8 stars, plus two additional, traditional building structures were simulated with the AccuRate building thermal simulation program. A new overheating analysis is proposed based on the combination of the Excess Heat Factor and the Adaptive Comfort Model. Although the uninsulated, double brick scenario required significantly more heating, that configuration also outperformed many scenarios with higher star ratings during summer. A higher star rating did not necessarily coincide with a decrease in cooling consumption, demand and overheating. Consequently, the integration of heat stress resistance in the Nationwide Energy Rating Scheme would be advantageous to avoid building new homes with potentially lower coping capacity and increased dependence on air-conditioning.