Australian Assessment Pathways
NatHERS, BASIX and BESS can all appear within Australian building projects, but they apply in different jurisdictions, answer different assessment questions and produce different forms of documentation.
The three names are often grouped together because each can influence the design and documentation of a residential development. That does not make them interchangeable. NatHERS is a residential energy-rating framework. BASIX is a New South Wales residential sustainability requirement. BESS is a Victorian planning-stage sustainable design assessment.
The correct starting point is usually the project location, building type and approval pathway. A house in New South Wales may need BASIX together with NatHERS modelling. A Victorian apartment development may need BESS at planning stage and NatHERS as a separate residential energy assessment. A Victorian commercial development may require BESS but would not use NatHERS.
This guide compares the role of each framework without replacing the detailed requirements of the individual pathways. For project-specific guidance, review the relevant council, planning authority and building approval requirements.
In Brief
What Is the Main Difference?
Residential Energy Rating
NatHERS
Assesses and rates the expected energy performance of residential dwellings.
NSW Residential Requirement
BASIX
Assesses water, energy and thermal performance for applicable residential development in New South Wales.
Victorian Planning Assessment
BESS
Assesses sustainable design measures for development proposals at the Victorian planning permit stage.
A project may require more than one of these pathways because a planning assessment, state sustainability certificate and residential energy rating can perform separate roles.
Assessment Context
Why Are NatHERS, BASIX and BESS Often Confused?
All three frameworks can affect residential design decisions and may refer to matters such as building fabric, glazing, energy use or environmental performance. They can also appear during overlapping stages of project documentation.
The important distinction is that they do not hold the same regulatory or technical territory. NatHERS provides energy-performance ratings for homes. BASIX is embedded within the NSW residential planning and approval system. BESS supports the assessment of sustainable design within Victorian planning.
Confusion usually occurs when the name of an assessment is treated as a complete description of the project’s sustainability obligations. In practice, the approval authority may require several coordinated documents, each addressing a different part of the proposed development.
Project Starting Point
Which Assessment Should You Check First?
Confirm the project location. BASIX applies within New South Wales, while BESS belongs to the Victorian planning context. NatHERS is a national residential rating framework.
Identify the building type. NatHERS applies to residential dwellings. BASIX applies to eligible NSW residential development. BESS Buildings can also apply to commercial, industrial and mixed-use proposals.
Check the approval stage. BESS is purpose-built for Victorian planning permit assessment. BASIX forms part of the NSW residential approval pathway. NatHERS may support building compliance or another assessment.
Review the required output. The project may need a NatHERS certificate, BASIX Certificate, BESS report or a combination of these documents.
Residential Energy Performance
What Is NatHERS?
NatHERS stands for the Nationwide House Energy Rating Scheme. It provides a nationally consistent framework for assessing the energy performance of residential dwellings.
The thermal assessment produces a rating from 0 to 10 stars based on the predicted heating and cooling energy needed to maintain comfortable internal conditions. The modelling considers the local climate together with the dwelling’s form, orientation, construction, insulation, glazing and shading.
NatHERS can also include a separate Whole of Home rating out of 100. This assessment considers the energy used by major appliances and services, together with energy generated or stored onsite.
What Does NatHERS Not Replace?
A NatHERS rating is not a complete state planning approval or broad sustainability assessment. It evaluates residential energy performance within its defined scope.
In New South Wales, NatHERS modelling may be used to support the thermal-performance component of BASIX, but the BASIX Certificate remains a separate project requirement. In Victoria, NatHERS results may support particular BESS credits or building compliance documentation, but the NatHERS certificate does not replace the BESS report.
The separate Whole of Home assessment should also not be confused with the thermal star rating. The two ratings examine different aspects of residential energy performance.
New South Wales Residential Sustainability
What Is BASIX?
BASIX stands for Building Sustainability Index. It is a New South Wales sustainability assessment framework for residential development.
The BASIX assessment addresses water efficiency, energy use and thermal performance. Project information and selected commitments are entered into the BASIX tool, and the resulting BASIX Certificate records the measures required for the proposed development.
Depending on the residential project and selected pathway, NatHERS modelling may be used to demonstrate thermal performance. BASIX remains broader than the NatHERS thermal rating because it also assesses water and energy commitments within the NSW approval context.
Is BASIX the NSW Version of BESS?
Not exactly. BASIX and BESS both consider more than one sustainability topic, but they sit within different planning systems, apply to different project types and produce different assessment outputs.
BASIX is a NSW requirement focused on residential development. BESS is a Victorian local-government assessment framework that can apply to residential, commercial, industrial and mixed-use buildings, together with a separate pathway for eligible residential subdivision applications.
The frameworks should therefore be understood through their own jurisdiction and approval pathway rather than treated as direct state equivalents.
Victorian Planning Assessment
What Is BESS?
BESS stands for Built Environment Sustainability Scorecard. It is an online assessment framework created by Victorian local governments to support sustainable design assessment at the planning permit stage.
BESS Buildings can apply to houses, townhouses, apartment buildings, commercial developments, industrial developments and mixed-use proposals. A separate BESS Subdivisions pathway is available for residential subdivision applications where lots and supporting infrastructure are assessed before individual buildings are proposed.
The BESS report records the applicable credits, category results, project score and supporting evidence. It may be used to support a council-required Sustainable Design Assessment or Sustainability Management Plan.
What Does a BESS Report Not Replace?
BESS organises and assesses project information against applicable sustainability credits. It does not automatically replace the broader written planning response where a council requires a separate Sustainable Design Assessment or Sustainability Management Plan.
It also does not replace the technical assessments used to substantiate particular credits. A residential project may rely on NatHERS results. Integrated water management credits may rely on separate stormwater modelling. Other credits may require daylight, ventilation, landscape, waste or specialist project evidence.
The BESS report records the relevant commitment or result while the underlying assessment remains a separate technical scope.
Side-by-Side Comparison
NatHERS vs BASIX vs BESS
NatHERS
Where Does It Apply?
A national residential rating framework applied through relevant state, territory, building compliance and voluntary rating pathways.
BASIX
Where Does It Apply?
Applicable residential development within the New South Wales planning and approval system.
BESS
Where Does It Apply?
Victorian planning applications where the relevant council requires BESS or related ESD information.
NatHERS
What Does It Produce?
A thermal star rating and, where applicable, a separate Whole of Home energy-performance rating.
BASIX
What Does It Produce?
A BASIX Certificate recording the applicable project inputs, targets and residential sustainability commitments.
BESS
What Does It Produce?
A BESS report showing applicable credits, evidence requirements, category results and the overall project score.
Combined Requirements
Can One Project Need More Than One Assessment?
Yes. These frameworks are not always alternatives. They can sit alongside one another because they assess different aspects of the project.
A New House in New South Wales
The project may require a BASIX Certificate, with NatHERS modelling used to demonstrate the dwelling’s thermal performance. BASIX remains the broader NSW residential sustainability pathway.
A Victorian Apartment Development
The planning application may require BESS and separate written ESD documentation. NatHERS may also be needed for the apartments and may provide evidence for relevant BESS credits.
A Victorian Commercial Development
BESS may apply during planning where required by council. NatHERS would not apply because it is a residential rating framework, while BASIX would not apply because the project is outside New South Wales.
A Mixed-Use Victorian Development
BESS may assess the broader development at planning stage, while NatHERS may separately apply to the residential dwellings within the mixed-use project.
Project Coordination
Why Should the Assessment Pathway Be Confirmed Early?
Each pathway relies on project information that may need to be reflected in the drawings, schedules and specifications. When the required assessments are identified late, the project team may discover that key information is missing or that design assumptions are inconsistent across documents.
Early review can clarify which framework owns each requirement. NatHERS should address residential energy performance. BASIX should coordinate the applicable NSW residential sustainability commitments. BESS should record the planning-stage credits and evidence relevant to the Victorian proposal.
Keeping these functions separate reduces duplicated reporting and helps ensure that the final assessment outputs correspond with the same design revision.
Frequently Asked Questions
NatHERS, BASIX and BESS FAQs
Is NatHERS the same as BASIX?
No. NatHERS is a residential energy-rating framework. BASIX is a NSW residential sustainability assessment covering water, energy and thermal performance. NatHERS modelling may form part of the BASIX thermal-performance pathway.
Is BESS the Victorian equivalent of BASIX?
No. Both frameworks consider multiple sustainability topics, but BASIX is a NSW residential requirement and BESS is a Victorian planning-stage assessment that can also apply to non-residential and mixed-use development.
Can a NSW project need both BASIX and NatHERS?
Yes. BASIX may be the broader NSW residential requirement, while NatHERS modelling is used to assess the thermal performance of the dwelling or dwellings.
Can a Victorian project need both BESS and NatHERS?
Yes. BESS may be required for the Victorian planning submission, while NatHERS separately assesses residential energy performance and may support relevant BESS evidence.
Does BESS only apply to residential projects?
No. BESS Buildings can apply to houses, townhouses, apartments, commercial buildings, industrial developments and mixed-use proposals. A separate BESS Subdivisions pathway is available for residential subdivision applications.
Does a BESS report replace NatHERS?
No. BESS may record or rely on NatHERS results for applicable residential credits, but it does not perform the NatHERS thermal or Whole of Home assessment.
How do I confirm which assessment applies?
Start with the project location, building type, approval pathway and any council or certifier requirements. These factors establish whether NatHERS, BASIX, BESS or a combination of assessments is likely to be required.
Related Knowledge
Explore Each Assessment Pathway
Assessment Pathway Review
Not Sure Which Assessment Your Project Requires?
Send the available plans, project location and approval information for an initial review. Certified Energy can help clarify whether NatHERS, BASIX, BESS or a combination of assessment pathways is likely to apply.
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