Residential energy efficiency standards

On 1 May 2024, changes were made to the National Construction Code (NCC) 2022 which will improve residential energy efficiency standards in new homes. The Modern Homes residential energy efficiency standards have been implemented through amendment of the existing Queensland Development Code 4.1 – Sustainable Buildings (PDF, 371.03 KB).

The changes improve the energy efficiency of the building shell, and for the first time, account for the energy usage of household appliances and equipment. Features like house orientation and better insulation may go unnoticed, but they make a positive difference to the comfort and energy costs of a new home.

These changes :

  • make homes more comfortable to live in
  • provide cost-of-living savings on energy bills over the life of the home
  • provide a greener future through emissions reduction.

What this means

The thermal performance of the building shell is generally assessed through a star rating system, although other methods of compliance are available.

New houses and units now require:

  • 7-star energy equivalence rating (out of 10) for the building shell (roof, walls, windows and floors).
  • Whole of Home energy budget that promotes energy efficient appliances and equipment (including air-conditioners, hot water heaters and lighting) and on-site renewable energy e.g. solar photovoltaic (PV) system.

7-star energy equivalence rating for homes

The 7-star standard applies to all new houses and townhouses (class 1 buildings) and the enclosed garage (class 10a buildings) attached to the class 1 building, and all new units in a multi-unit residential building (class 2).

Units within a multi-unit residential building must collectively achieve an average of 7-stars for the whole building, with no individual unit to be less than 6-stars.

Building designers and architects can use a range of styles and energy efficient features to comply with the 7-star standard. A 7-star home may not look any different from an average home, but it will have a better energy performance.

Many energy-efficient (or ‘passive design’) features can be included at little or no extra cost, where possible, such as:

  • northern orientation of living areas and good room configuration to account for solar access and natural ventilation
  • minimising the area of east and west facing walls and windows
  • well-located and designed windows to capture breezes
  • shading of walls and windows with roof eaves, awnings and external blinds
  • treated glazing, like low-e glass or tinted, particularly for western facing windows
  • insulation in the roof space (e.g. reflective foil under roofing and batts above the ceiling) and to external walls
  • ventilating the roof space via roof and eave vents
  • lighter coloured roof and external walls to reflect heat
  • ceiling fans in living areas and bedrooms to promote air movement
  • well-designed outdoor living area (e.g. a deck or verandah with good orientation).

Homeowners should discuss how the 7-star standard applies to their proposed design and what features are to be included with their building designer or architect, house energy assessor and building certifier early in the design stage.

Optional credits for outdoor living areas can be used towards meeting the 7–star minimum standard for houses and townhouses and units.

Whole of Home assessment and rating

The new energy efficiency standards include the introduction of a Whole of Home rating to measure the energy use of the home. In simple terms, the rating considers the energy used in a household for heating, cooling, appliances and equipment, minus any energy generated from solar panels.

Whole of Home assessments aim to lower energy costs by helping homeowners make cost-effective choices about their home’s appliances and equipment. Homeowners, designers and builders can explore the trade-offs and benefits of different technologies, appliance efficiencies and thermal performance to create a home and appliance design that works for them and their budget.

A Whole of Home assessment involves the following appliances and equipment:

  • Lighting
  • Heating and cooling
  • Hot water
  • Swimming pool and spa pumps
  • Cooking and plug-in appliances.

Onsite energy generation and storage (e.g. solar PV and batteries) can also form part of a Whole of Home assessment where these are included in the design documentation.

The Whole of Home rating scale ranges from 0 to 100 – a poor energy performing home would rate under 40, while a score of 100 is a net zero energy value home. A rating over 100 is possible where the home is producing more energy than it uses. Ratings at 100 or above mean the home will have low or no energy bills.

The new NCC 2022 residential energy efficiency standards mean new houses and townhouses will need to achieve a Whole of Home rating of 60 (out of 100) and new units a rating of 50 (out of 100).

There are many appliance combinations that can be used to achieve a high Whole of Home rating. An efficient water heating system and appropriately sized space heating or cooling systems can save money and ensure the home is comfortable and resilient in hot and cold climates. On-site renewable energy generation can also help off-set the home’s energy use.

The relationship between a home’s thermal performance rating and its Whole of Home rating means that increasing thermal performance will increase the Whole of Home rating. This is because the heating and cooling energy needs will be lower in a home with a higher thermal performance rating.

Assessing residential energy efficiency compliance

The two main existing compliance options that are available to house energy assessors to assess residential energy efficiency compliance for houses, townhouses and apartments are:

NatHERS software

The same software tools that are used for thermal performance assessments are used for assessing compliance with the NCC Whole of Home energy efficiency requirements.

All new assessments must be undertaken using the latest version of the chosen software unless an exemption is provided by the relevant building authority. BERS Pro, AccuRate Home, Home Energy Rating Optimisation (HERO) and FirstRate5 software tools have been accredited by NatHERS for use in performing thermal performance and Whole of Home assessments and the issuance of Whole of Home certificates.

NatHERS-accredited software is able to provide a whole of home rating for apartment units where hot water and space conditioning are decentralised, but currently does not offer a Whole of Home option for apartments with centralised services. However, the NatHERS Administrator expects that software tools will be available to assess Class 2 buildings with centralised services from 2025.

Deemed to Satisfy Elemental Provisions

This option provides a prescriptive approach to complying with thermal and Whole of Home performance requirements. The elemental provisions are in the deemed to satisfy (DTS) provisions of the NCC and when followed in their entirety, form a DTS Solution.

This compliance option is prescribed in Australian Building Codes Board NCC 2022 as follows:

  • for houses in the DTS Provisions of Volume Two, H6D2(1)(b) and H6D2(2)(b)
  • for apartments in the DTS Provisions of Volume One, J2D2(2)(b) and J2D2(3)(a)(i), (b) and (c).

Impact

For a new home in Queensland, the new residential energy efficiency standards will provide an average electricity saving of $185 per year across Queensland’s 4 climate zones. The region (climate zone) where a person lives will influence the energy efficiency features needed for compliance.

The Australian Building Codes Board (ABCB) commissioned an independent analysis for jurisdictions to transition to the new standards from 2019 to 2022. The former Department of Energy and Public Works commissioned a cost-benefit analysis to investigate the impacts for Queensland of adopting the NCC 2022 residential energy efficiency standards. This analysis identified a net benefit of at least $506 million for the Queensland community.

The uplift in standards is estimated to reduce emissions by 4.63 million tonnes.

More information

For more information about the NCC 2022, visit the ABCB website.