Overview of changes – energy efficiency and condensation

Over the last 3 years, we’ve been working with our stakeholders to develop important changes to residential energy efficiency provisions in the NCC. We’ve introduced new provisions and made some improvements to the existing provisions. It’s important you know what will impact your work.

The new residential energy efficiency provisions apply to houses and other low rise multiple dwelling projects (Class 1 buildings) and apartment buildings (Class 2 sole-occupancy units and Class 4 parts of buildings).

There are 2 key elements to the changes.

1. The minimum level of thermal performance of new homes is raised to the equivalent of 7 stars under the Nationwide House Energy Rating Scheme (known as NatHERS). This will deliver a significant improvement in thermal comfort for occupants.
2. A new whole-of-home, annual energy use budget now needs to be met by new homes.
   This budget applies to the energy use of a home’s heating and cooling equipment, hot water systems, lighting and swimming pool and spa pumps. Renewable energy systems, such as rooftop solar panels, aren’t mandatory but can also be installed to help keep a home’s energy use under the required budget.

This approach means NCC 2022 provides a mix of practical solutions for homes that can be customised to the climate and location of each build. 

Here’s a summary of the main updates to the Performance Requirements and options for demonstrating compliance:

• There are 2 new Performance Requirements for:
  • thermal performance (H6P1 of Volume Two, J1P2 of Volume One); and
  • energy usage (H6P2 of Volume Two, J1P3 of Volume One).
• Improvements to the existing reference building Verification Method for houses (H6V2 of Volume Two (2019: V2.6.2.2)), which is based on using non-NatHERS energy modelling software.
• A new reference building Verification Method for Class 2 apartments (J1V5 of Volume One), which is also based on the use of non-NatHERS energy modelling software.
• Updated Deemed-to-Satisfy (DTS) Provisions to reflect the increase in thermal performance to the equivalent of 7 stars and the new annual energy use budget. Two compliance pathways are available. You can use:
  • NatHERS software (Specification 42 of Volume Two (2019: 3.12.0), J2D2(2) and (3) of Volume One (2019: J0.1)) or
  • prescriptive elemental provisions (Section 13 of the ABCB Housing Provisions (2019: Part 3.12), J2D2(2) and (3) of Volume One (2019: J0.1)).
• Updated limits in the ABCB Standard for NatHERS Heating and Cooling Load Limits.
• A new ABCB Standard for Whole-of-Home Efficiency Factors has been developed to determine compliance with the new annual energy use budget

An infographic providing more information on these provisions is also available. The information in this infographic is available as a text transcript.

There have also been important changes to commercial energy efficiency provisions in the NCC, including:

• New Performance Requirements now require certain buildings to have features which facilitate the future installation of on-site renewables and electric vehicle charging (B1P1(2)) and J1P4 of Volume One).
• The NABERS Energy Verification Method is expanded to Class 2 common areas, Class 3 buildings and Class 6 shopping centres (J1V1 of Volume One (2019: JV1)).
• New DTS Provisions to facilitate the future installation of electric vehicle charging equipment in carparks associated with Class 2, 3, 5, 6, 7b, 8 or 9 buildings (J9D4 of Volume One).
• New DTS Provisions to facilitate the future installation of solar photovoltaics and battery storage (B1D3(a) and J9D5 of Volume One). This excludes houses.

Improvements have been made to the condensation management provisions for residential buildings. These include:

• A mould index added to the existing Verification Method (F8V1 of Volume One (2019: FV6) and H4V5 of Volume Two (2019: V2.4.7)).
• Additional DTS Provisions for vapour permeance of certain external wall and roof space materials and enhanced ventilation requirements for certain rooms and roof spaces (F8D1 of Volume One (2019: F6.0) and Part 10.8 of the ABCB Housing Provisions (2019: Part 3.8.7).
• Additional provisions for tightly sealed buildings in the existing Verification Method (H6V3 of Volume Two (2019: V2.6.2.3) and J1V4 of Volume One (2019: JV4)).

The condensation management changes build upon the initial provisions introduced in NCC 2019. The changes are intended to help further reduce condensation risk.

These changes are the result of over 3 years of development and consultation by the ABCB, which commenced when Energy Ministers requested the NCC be updated in consideration of the national Trajectory for Low Energy Buildings.

This article was updated on 19/06/2023