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Large boarding houses

We have a new streamlined process for completing a BASIX assessment of a large boarding house.

It is no longer mandatory to obtain a BASIX certificate for the erection of a new large boarding house, or alterations to an existing large boarding house, as this development is no longer BASIX development. Specifically, the definition of a BASIX building in the Environmental Planning and Assessment Regulation 2021 excludes a boarding house, hostel or co-living housing that accommodates more than 12 residents, or has a gross floor area exceeding 300 square metres.

The requirements of the National Construction Code, as administered by your consent authority, continue to apply.

If you previously generated a BASIX certificate for a large boarding house and received development consent, and are making revisions to the design, you should check the conditions of consent for your development. If the consent conditions do not state that a BASIX certificate is required, you do not need to obtain a revised BASIX certificate. If the consent conditions state that a BASIX certificate is required, you should seek legal advice and/or discuss with the consent authority.

If you decide to revise an existing BASIX certificate, please follow the instructions below.

We have a new streamlined process for completing a BASIX assessment of a large boarding house, (which includes student accommodation) provided it meets all the criteria below:

  • it is designed to accommodate more than 12 people, or the total floor area exceeds 300 m2
  • at least 80% of the dwellings are less than 35 m2, and
  • it only comprises residential flat buildings.

It is called the Large boarding house thermal comfort method. It is similar to a standard BASIX assessment, except for the following differences:

  • On the ‘Project Type’ tab, under residential flat buildings, you must tick the ‘Project is a large boarding house’ box.
  • In the Thermal Comfort section, you must select ‘Large boarding house’.

So long as the project meets all the eligibility criteria listed above, the Tool will automatically enter values for heating and cooling loads equivalent to the heating and cooling caps in the climate zone of the project.

That is, you do not have assess the thermal comfort of the project as part of the BASIX assessment. Instead, the thermal comfort must be assessed at a later stage (i.e. the construction certificate stage) against the Section J requirements of the National Construction Code (NCC) – Volume 1The BASIX Certificate will contain an additional commitment requiring an assessment against the Section J requirements of the NCC – Volume 1 prior to obtaining a construction certificate.

You must complete all other sections of the BASIX assessment, including passing the Energy and Water sections.

Please also note that the BASIX certificate will not show the heating load and cooling load values because a thermal comfort assessment has not been completed.

Why is there a different process for large boarding houses?

There is a different process because NatHERS accredited software is unsuitable to model the thermal comfort of individual boarding house rooms.

What if my project meets some but not all of the eligibility criteria?

If the boarding house meets the first eligibility criteria, but does not meet the second or third criteria, you should apply for an alternative assessment as a large boarding house. This may be where the project:

  • contains a mix of class 3 boarding house dwellings and larger class 2 apartments, or
  • comprises a large boarding house and a single dwelling house on the same site.

If the development is a small boarding house (i.e. designed to accommodate 12 people or less, and has a total floor area of 300m2 or less), you should complete a BASIX assessment using the single dwelling tool and assess the thermal comfort of the building as a whole.


If you have any questions, please email [email protected] and include ‘BASIX – large boarding house’ in the subject.

Last updated: 16/08/2022