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Thermal Performance

Simulation method


The Simulation method allows for a wider selection of building materials, shading devices and insulation, often reducing the need for improved glazing and other added building costs.

In the Simulation method, you will need to:

To pass the thermal performance section using this method, the heating and cooling loads must be below the maximum loads (as calculated by BASIX based on your climate zone).

The Simulation method is not available for alterations and additions except in special circumstances. Please refer to the guide on using Simulation for alterations and additions.

Thermal performance protocol

The BASIX thermal performance protocol applies to the Simulation method of thermal performance assessment. It establishes requirements for:

  • accreditation of organisations that may accredit assessors to conduct simulations, and the accreditation of assessors by such organisations
  • software that can be used by accredited assessors to conduct simulations
  • how simulations are to be conducted by accredited assessors.

The BASIX thermal performance protocol refers extensively to the requirements in the NatHERS technical notes. It also establishes the hierarchy of interpreting the requirements in conjunction with the NatHERS technical notes. Where there are differences between the protocol and the NatHERS technical notes, protocol requirements prevail.

View the current thermal performance protocol (dated 07/06/2024)

If your project is eligible to meet the pre-1 October 2023 standards, the BASIX thermal comfort protocol (dated 27/11/2020) applies.

Last updated: 21/06/2024