Energy efficiency of residential buildings

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The energy efficiency requirements for housing (Class 1 buildings and certain Class 10 buildings and structures) are contained in the Building Code of Australia (BCA) Volume Two, which forms part of the National Construction Code. The Performance Requirements for new housing take into account both the thermal performance of the house and performance of its regulated domestic services.

Options for complying with energy efficiency requirements

The options to meet the energy efficiency Performance Requirement of a house can be achieved through Deemed-to-Satisfy provisions or the use of a Performance Solution.

Part 2.6 of the BCA contains Performance Requirements for Energy Efficiency and Part 3.12 provides Deemed-to-Satisfy Provisions. The BCA is available free online from the Australian Building Codes Board website.


The Deemed-to-Satisfy provisions consist of two compliance options:

  • Option 1: Energy rating in accordance with clause 3.12.0(a)(i) of the BCA.
  • Option 2: Elemental provisions in accordance with clause 3.12.0(a)(ii) of the BCA.

In addition to either option, the provisions for Services under Part 3.12.5 of the BCA must also be addressed.

Western Australia additions

The BCA Schedule 1, State & Territory Appendices contains additional provisional for Western Australia with regards to water efficiency.

Performance Solutions

A Performance Solution must be prepared in accordance with Part A2.2 of the BCA and demonstrate compliance with the relevant Performance Requirements by using one or more of the following assessment methods:

  • Evidence of Suitability in accordance with NCC Part A5;
  • Verification Method which for P2.6.1 includes V2.6.2.2 VURB;
  • Other Verification Method that shows compliance with the Performance Requirements to the satisfaction of the certifying building surveyor;
  • Expert Judgement; and
  • Comparison with the DTS Provisions.

WA Alterations and Additions Protocol for Energy Efficiency

Building and Energy has supported an industry-led project to provide a practical building solution that enables alterations and additions in Class 1 or attached Class 10 buildings to meet the energy efficiency requirements.  This project has resulted in the development of a WA Alterations and Additions Protocol for Energy Efficiency (the Protocol).

The Protocol provides the basis of a performance solution that can be developed to demonstrate compliance with performance requirements P2.6.1 and P2.6.2 for alterations and additions in Class 1 and Class 10 buildings.

Check sheets

Building and Energy no longer provides verification sheets or check lists to assist with energy efficiency assessments.  The BCA 2012 check sheets and tools previously available on our website for new houses are outdated and should not be used.  

Documentation of decisions

Decisions made under the BCA should be fully documented and copies of all relevant documentation should be retained.

Examples of the kind of documentation which should be prepared and retained include:

(a)      Details of the Building Solution including all relevant plans and other supporting documentation.

(b)      In cases where a Performance Solution has been proposed—

  1. details of the relevant Performance Requirements; and
  2. the Assessment Method or methods used to establish compliance with the relevant Performance Requirements; and
  3. details of any Expert Judgement relied upon including the extent to which the judgement was relied upon and the qualifications and experience of the expert; and
  4. details of any tests or calculations used to determine compliance with the relevant Performance Requirements; and
  5. details of any Standards or other information which were relied upon.

 It is the responsibility of the registered building surveyor to request sufficient documentation to be satisfied the building will meet the relevant provisions. 

Industry Bulletin 140 – National Construction Code 2019 Volume Two: Complying with energy efficiency requirements

Industry Bulletin 140 provides a summary of the residential energy efficiency requirements in Western Australia from 1 May 2021 until the next edition of the National Construction Code is adopted.

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