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NCC Energy Efficiency Verification Using Reference Building Method

January 09, 2020

The Australian Building Codes Board (ABCB) have released a video providing useful guidance on how to use and interpret the NCC verification using reference building method to show a house design meets the minimum energy efficiency requirements. The video can be viewed here.

The video has been developed to assist practitioners to further understand the method and provide detail on the correct use of the method.

NCC 2019 changes

The reference building method was amended as part of the NCC 2019 changes to address concerns that there were instances where the reference building method was not being used as intended.

The changes to the method now includes prescriptive inputs or parameters that need to be used in applying the method and clarify that NatHERS energy efficiency rating tools used for 6-stasr assessments (BERs Pro, Accurate and FirstRate5) are not to be used when using the reference building method. The ABCB video provides information on those changes.

Transitional arrangements

Whilst the majority of the changes to NCC 2019 took effect in most states from 1 May 2019, the energy efficiency provisions, including the changes to the reference building method, have been subject to additional transitional time and will take effect from 1 May 2020.

Given the nature of the changes to the reference building method have been made to address concerns about the application of the method, HIA would encourage practitioners who use this method to note the changes incorporated in NCC 2019 as part of applying the method as soon as possible to ensure designs being considered between now and 1 May will still be permitted.

HIA would also encourage practitioners to discuss these and other NCC 2019 energy efficiency changes with your relevant energy assessor as part of future building designs.

About the Verification Using a Reference Building method - V2.6.2.2

By way of further background, the reference building method is included in NCC Volume Two at V2.6.2.2, and is a method that can be used to comply with the energy efficiency requirements as an alternative to using the NCC elemental provisions or the NatHERS energy/star rating method (using Accurate, First Rate 5 or BERS Pro).

V2.6.2.2 is a comparative approach that assesses the heating load and/or cooling load of the proposed building (typically measured in MJ/m2 annum) and compares it to the heating load and/or cooling load of that house’s design had it been built to the Deemed-to-Satisfy Provisions of Parts 3.12.1 to 3.12.4.

Similar to the star rating method, V2.6.2.2 requires the use of software/modelling tools for the energy assessment of the building.

A key aspect of the method is that it provides flexibility in meeting the NCC energy efficiency provisions as it allows trading between different elements of the building fabric to achieve the required heating load and/or cooling loads.

For example the method could allow for a design that incorporates a feature window on the front façade of a dwelling but its performance may be lower than required of windows for the house generally. The method could facilitate the use of that window by increasing the insulation in the walls or similar to provide a comparative level of energy efficiency performance overall.

Further information

HIA has produced a number of relevant information sheets that provide further information on the NCC 2019 changes and on the NCC energy efficiency provisions more broadly. These include:

  • Information on the NCC 2019 Changes here
  • NCC energy efficiency compliance paths here
  • Information on the Reference building method here

The ABCB video can be viewed here and the ABCB have also produced an updated Information Handbook on energy efficiency for NCC Volume Two that provides a worked example of applying the reference building method and can be accessed here

For further clarification and information on these matters HIA members can contact HIA on 1300 650 620 or technical@hia.com.au