Jan 2024

Media Release: Beyond 7 stars: addressing gaps in ACT’s energy efficiency mandate

7 stars is necessary for new homes, however existing homes face increasing challenges.

Image showing aerial view of Canberra suburb with houses and text "Beyond 7 stars" Addressing gaps in ACT energy efficiency mandate"

Canberra, ACT


  • Canberra’s new 7-star energy rating mandate for renovations increases complexity and costs for existing homes.
  • Achieving 7 stars in poorly designed existing homes is challenging, risking discouragement of homeowners undertaking affordable efficiency and liveability upgrades.
  • The absence of airtightness standards in the new mandate is a missed opportunity for cost-effective energy efficiency improvements.

In response to the Australian Capital Territory’s (ACT) adoption of the National Construction Code (NCC) 2022 energy efficiency provisions, Powerhaus, a leader in building energy efficiency, today highlights the challenges posed by the new 7-star energy efficiency mandate. This mandate, applicable to both new builds and existing homes, marks a significant shift in building standards.

While Powerhaus applauds the move towards higher energy efficiency in new homes, the extension of this 7-star requirement to existing homes undergoing renovations or extensions is a cause for concern. This change introduces significant complexities and potential financial burdens for homeowners, especially for those with properties not initially designed with energy efficiency in mind.

The primary challenge lies in retrofitting existing homes to meet these stringent standards. For instance, a poorly oriented house might require extensive and expensive modifications to achieve the 7-star rating – or may not meet it at all. This approach encourages knock-down rebuilds and discourages sensible adaptations of Canberra’s existing housing stock.

Powerhaus advocates for a more practical approach to enhancing energy performance in existing homes. A straightforward compliance pathway, such as a checklist for improving insulation, window performance, and airtightness, could offer clarity and reduce costs. This approach would encourage homeowners to make sustainable upgrades without the need for extensive renovations or consulting.

Furthermore, Powerhaus highlights a significant oversight in the new legislation – the absence of airtightness standards. Increasing airtightness is a cost-effective method to improve a home’s energy efficiency, yet it remains unaddressed in the current standards. Powerhaus Director Andrew Pickard emphasizes,

“Incorporating airtightness into the building code would significantly enhance energy efficiency across the board. Its exclusion is a missed opportunity for accessible and widespread energy improvements.”

As the NCC2022 provisions take effect, Powerhaus remains committed to working with homeowners and industry professionals to navigate these new challenges and continue advancing sustainable building practices.

For more information on Powerhaus Engineering and how we can assist with your building projects under the new standards, see our energy rating service and our Australian-first energy efficiency design app.

About ACT energy efficiency star ratings

New and existing homes needing building approval in Canberra will now need to meet a 7-star energy efficiency rating, effective from 15th January 2024. This update includes a whole-of-home energy use component. For renovations and extensions requiring building approval, alternative compliance pathways are available, however they can be complex and expensive. Previously, the requirement was a 6-star minimum.