If you are just relocating a house, then you don’t need a BASIX certificate.
If you carry out alterations and additions to the house after relocation or to make it suit the new site, then you would need a BASIX certificate for the alterations.
But if you just place it on the site as is, then you don’t need BASIX.
We base this on Planning Circular PS 21-016 issued by the Dept of Planning.
The circular is mostly about houses designed to be transportable but at the bottom of p3 it mentions the relocation of BASIX affected buildings. See the extract below. It’s dated Dec 2021 so is current.
Relocation of BASIX-affected buildings
When a BASIX-affected building is moved from one site to another site it is exempt from the requirement for a BASIX certificate.
We would always suggest checking with your certifier or Council to ensure they agree with this interpretation in your particular situation.
A further note to be added, which may be relevant in this situation, is that BASIX only applies if the estimate cost of the development is $50,000 or more.
A copy of Planning Circular PS 21-016 can be found via the link below.
Also note the definition of a BASIX development in the regulations. Refer to this link: https://legislation.nsw.gov.au/view/html/inforce/current/sl-2021-0759#dict