NSW Building Compliance
BASIX and Section J both relate to building performance and approval documentation, but they apply to different parts of the Australian building compliance system.
BASIX is the NSW sustainability assessment pathway for residential development. Section J forms part of the National Construction Code and applies to energy efficiency requirements for relevant commercial and other non-residential buildings.
A standard NSW house will generally require BASIX rather than Section J. A commercial building will generally require Section J rather than BASIX. A mixed-use development may require both, with different compliance pathways applying to different parts of the building.
The correct answer depends on the project location, building classification, proposed use, approval pathway and whether the development contains both residential and non-residential areas.
In Brief
BASIX is used for many residential developments in New South Wales and considers water, energy use and thermal performance. Section J addresses energy efficiency requirements for relevant commercial and non-residential buildings under the National Construction Code. Mixed-use developments may require both pathways.
BASIX stands for Building Sustainability Index. It is a NSW assessment and certification pathway used for residential development.
The assessment considers how a residential project is expected to perform in relation to:
The completed BASIX Certificate records the commitments that need to be incorporated into the project documentation and delivered as part of the approved development.
A complete explanation of the pathway, documentation and assessment process is available in the BASIX Knowledge Hub.
BASIX is commonly relevant to residential development in New South Wales.
This may include:
The specific requirements depend on the project type, proposed work and approval pathway. Where thermal performance modelling forms part of the residential assessment, BASIX may also work alongside a NatHERS assessment.
Section J is the part of the National Construction Code that addresses energy efficiency requirements for relevant commercial and other non-residential buildings.
Unlike BASIX, Section J is not limited to New South Wales. It sits within the national building compliance framework and applies according to the relevant NCC edition, building classification, project scope and jurisdictional requirements.
A Section J Report may address requirements relating to:
The Section J Knowledge Hub explains the broader compliance pathway, required documentation and the relationship between prescriptive and performance-based assessment methods.
Section J is commonly relevant to commercial and non-residential building work that needs to demonstrate energy efficiency compliance under the NCC.
Projects may include:
The building classification and scope of work should be confirmed before the assessment is commissioned. A building may appear residential or commercial from its design while being classified differently under the NCC.
| Topic | BASIX | Section J |
|---|---|---|
| Primary project type | NSW residential development | Relevant commercial and non-residential buildings |
| Geographic framework | New South Wales | National Construction Code, subject to jurisdictional adoption |
| Primary assessment territory | Residential water, energy use and thermal performance | Commercial building energy efficiency |
| Typical output | BASIX Certificate and recorded commitments | Section J Report or other NCC compliance documentation |
| Typical buildings | Houses, townhouses, apartments and residential alterations | Offices, shops, warehouses, schools, hotels and other non-residential buildings |
| Can both apply? | Yes, to the residential portion of a mixed-use development | Yes, to the commercial or non-residential portion of the same development |
Yes. A mixed-use development may require BASIX for its residential components and Section J compliance for its commercial or non-residential components.
For example, a development containing apartments above ground-floor retail premises may require:
The design team may need to separate the assessment areas according to their building classifications and uses. A single BASIX Certificate should not be assumed to address the commercial portion of the development, and a Section J Report should not be assumed to replace the residential BASIX requirements.
Early review can establish which areas follow the BASIX pathway and which areas need to be considered under Section J.
The size of an apartment building does not automatically make it a Section J project.
The residential dwelling component of a NSW apartment development generally follows the applicable residential compliance pathway. This commonly includes BASIX and may also include NatHERS thermal performance modelling.
However, the same development may contain separately classified spaces such as:
Those areas may require separate Section J assessment. Residential dwellings, common areas and commercial tenancies should therefore be reviewed according to their classification and use rather than being treated as one uniform assessment area.
Accommodation projects can be more difficult to categorise than standard houses or commercial offices.
The applicable pathway depends on the building classification, intended use, project description and approval documentation. Some accommodation projects may follow residential requirements, while others may need to demonstrate commercial energy efficiency compliance under Section J.
Where a development is not a standard dwelling, the classification should be confirmed before commissioning the assessment. This can prevent the project team from ordering the wrong report or discovering missing documentation later in the approval process.
The two pathways are often confused because they can address similar building elements.
Both may involve:
Both may also be required during the preparation of Development Application, Complying Development Certificate, Construction Certificate or building approval documentation.
The overlap in design inputs does not make the pathways interchangeable. BASIX remains a NSW residential sustainability pathway, while Section J remains part of the NCC commercial and non-residential energy efficiency framework.
No. Section J is the broader commercial energy efficiency framework. JV3 is one possible performance-based pathway within that framework.
Many commercial projects can demonstrate compliance by following the relevant Deemed-to-Satisfy provisions directly. A JV3 assessment may be considered where a modelling-based Performance Solution is more appropriate for the proposed design.
The choice between DTS and JV3 belongs to the commercial Section J pathway and does not change whether the residential parts of a NSW development require BASIX.
Start with the project location, building classification and proposed use.
The drawings, planning description, class of building and approval requirements will usually provide the information needed to establish whether the project requires BASIX, Section J or both.
The project does not need to be fully documented before an initial review can occur.
Useful starting information may include:
Early review is particularly useful for mixed-use, multi-residential, accommodation and adaptive-reuse projects, where the compliance boundaries may not be immediately obvious.
Certified Energy prepares BASIX Certificates and assessments for NSW residential development and Section J Reports for relevant commercial and non-residential buildings.
Where the correct pathway is unclear, our team can review the available documents and identify whether the project is likely to require:
You do not need to determine the complete compliance pathway before sending the project documents. An early review can help establish the correct assessment scope before the design and approval process progresses further.
BASIX is the NSW residential sustainability assessment pathway and considers water, energy use and thermal performance. Section J forms part of the National Construction Code and addresses energy efficiency requirements for relevant commercial and non-residential buildings.
A standard residential house in New South Wales will generally follow the BASIX pathway rather than Section J. The exact assessment requirements depend on the project type and scope.
Yes. BASIX may apply to the residential portion of a mixed-use development, while Section J may apply to retail, office or other non-residential components.
The residential dwelling component of a NSW apartment project generally follows the applicable residential pathway, which commonly includes BASIX and may include NatHERS. Commercial or separately classified areas may require Section J assessment.
No. BASIX and Section J belong to different compliance frameworks. A BASIX Certificate does not replace Section J documentation for commercial parts of a project, and a Section J Report does not replace BASIX where BASIX applies.
No. Section J is the broader commercial energy efficiency framework. JV3 is a modelling-based Performance Solution pathway that may be used for some commercial projects.
Review the project location, building classification, intended use and approval pathway. Where the development is mixed-use or the classification is unclear, the project documents should be reviewed before the assessment scope is confirmed.
Project Review
Send the available project documents to Certified Energy. Our team can review whether the development is likely to require BASIX, Section J or a combination of both.
Request a Project Review