Introducing the 7-Star Standard

The 2022 National Construction Code (NCC) mandates a new minimum thermal performance rating of 7 stars under the Nationwide House Energy Rating Scheme (NatHERS) for all new homes. Additionally, new homes must meet a minimum annual energy use budget, with most jurisdictions adopting this requirement nationwide, albeit with extended transition periods in a few states and territories.

Living in a 7-star energy-efficient, all-electric home could save approximately $450 annually on heating and cooling compared to the current 6-star standard. Moreover, this upgrade is expected to reduce emissions by 25%, equivalent to the emissions of one car. The impact on emissions is significant, with an estimated reduction of 46,000 tonnes in New South Wales, 31,000 tonnes in Queensland, and a substantial 72,000 tonnes per year in Victoria. 

Already, 16% of new housing meets or exceeds the 7-star energy rating, according to a 2022 CSIRO report, indicating that builders are already embracing the changes to the NCC. 

Key Efficiency Requirements in the 2022 NCC:

• Increase in minimum efficiency performance for the building shell (insulation, window glazing, etc.) from 6 to 7 stars through NatHERS.
• Introduction of a Whole-of-Home annual energy use budget for fixed appliances (hot water, heating and cooling, lighting, pool, and spa pumps), with potential offset via rooftop solar.
• Removal of the Victorian variation requiring specific water heaters or rainwater tanks, allowing more flexibility in hot water system choices.
• Removal of the Queensland variation allowing solar PV systems to offset 1 star credit.
• Requirements ensuring apartments are designed for easy and cost-effective retrofitting of solar systems and electric vehicle charging.

Practical Implications:

Achieving a 7-star rating is feasible through relatively straightforward and cost-effective adjustments, especially when design considerations are integrated early in the home-building process. Key enhancements from a 6-star to 7-star home may include optimized sun orientation for passive heating in winter and shading in summer, upgraded insulation tailored to local climates, high-performance glazing for better insulation, and strategic use of thermal mass within the building envelope. 

How We Can Assist You: 

NRG Efficient Homes is committed to supporting both existing and new clients through this transition. Engaging with our energy consultants early on and conducting preliminary assessments during the concept design stage can identify thermal performance issues before they become costly challenges during the building approval process. This proactive approach not only helps minimize upgrade expenses but also ensures compliance with the new standards, potentially saving thousands of dollars and preventing the frustration of last-minute design modifications.