The cost of a BASIX Certificate in New South Wales has two separate components: the official NSW Planning Portal fee and the professional fee for preparing the assessment.
The official portal fee is currently $5 per BASIX Certificate application. The professional assessment fee is separate and depends on the residential project type, number of dwellings, thermal-performance pathway, quality of the plans and level of design coordination required.
A straightforward alteration may require a different scope from a custom home, dual occupancy or townhouse development. Where NatHERS thermal simulation is required, the modelling and assessor documentation also form part of the professional scope rather than the $5 portal charge.
In Brief
The NSW Planning Portal currently charges $5 for a BASIX Certificate application. This is not the total cost of obtaining professionally prepared BASIX documentation.
A professional fee may also apply for reviewing the plans, completing the water and energy inputs, coordinating thermal performance, preparing any required NatHERS assessment, resolving design issues and generating documentation that aligns with the approval drawings. Because that work varies substantially between projects, an accurate fee normally requires a review of the available plans.
| Cost Component | Pricing Basis | What It Covers |
|---|---|---|
| NSW Planning Portal fee | Currently $5 | The government portal charge for a BASIX Certificate application. This fee may change and should be confirmed against the current NSW Planning Portal schedule. |
| Professional BASIX assessment | Project-specific | Plan review, assessment inputs, project coordination, target checking and preparation of the BASIX Certificate. |
| NatHERS thermal simulation | Where required | Thermal modelling of the dwelling, design review and preparation of the NatHERS Assessor Certificate by an accredited assessor. |
| Multiple dwellings | Based on project scope | Additional dwellings, orientations, dwelling types, shared systems and repeated or unique thermal models. |
| Revisions | Depends on the change | Updates required after changes to glazing, geometry, construction, insulation, water measures or energy systems. |
Important Distinction
The NSW Planning Portal fee pays for the BASIX Certificate application within the government system. It does not pay for an assessor or consultant to interpret the plans, prepare the assessment, undertake NatHERS modelling, resolve design issues or coordinate the commitments with the approval documentation.
A professional BASIX fee reflects the work required to translate the proposed residential design into a coordinated BASIX assessment. The exact inclusions should be confirmed in the consultant’s quote.
Depending on the project, the professional scope may include:
Some quotes include thermal modelling, while others separate BASIX and NatHERS into different line items. The scope should clearly state what documentation will be provided and how many rounds of design review or revision are included.
BASIX is not one identical task for every residential development. The amount of work depends on the project being assessed and how clearly that project has been documented.
Project Type
A new dwelling, alteration, addition, secondary dwelling, dual occupancy and multi-dwelling development can each require a different assessment scope.
Thermal Method
A project requiring NatHERS simulation involves detailed thermal modelling and accredited assessor documentation beyond the standard portal application.
Design Complexity
Complex floor plans, split levels, large glazed areas, multiple orientations and unusual construction systems can require more modelling and coordination.
Number of Dwellings
Additional dwellings may introduce different orientations, floor plans, glazing arrangements, services and separate thermal models.
Documentation
Clear, coordinated plans can be assessed more efficiently than drawings with missing dimensions, conflicting schedules or unresolved construction selections.
Design Changes
Changes made after modelling or certificate issue may require parts of the assessment and its supporting documentation to be repeated.
The project type is one of the first factors considered when preparing a BASIX quote. It indicates how much of the development needs to be documented and whether one or multiple dwellings are involved.
Pricing depends on the scope of the proposed work, the clarity of the existing and proposed drawings and the extent to which retained building elements affect the assessment.
A compact secondary dwelling may still require complete water, energy and thermal-performance information. Site relationships and shared or separate services may also need clarification.
A new home generally requires the complete envelope, glazing, water measures and energy systems to be assessed. Custom geometry or high-performance design requirements can increase the review scope.
Two dwellings may require separate design inputs or thermal models, particularly where their orientation, geometry, glazing or construction differs.
Pricing reflects the number of dwellings, repeated and non-repeated layouts, different orientations, shared services, common areas and the number of individual models or certificates required.
Where NatHERS thermal simulation is required, the assessor creates a digital thermal model of the proposed dwelling. This is a separate technical task from completing the water and energy sections of the BASIX application.
The modelling scope may be influenced by:
The consultant’s quote should indicate whether NatHERS modelling is included, whether the assessor certificate is included and what happens if the design changes after the first model has been completed.
Who can perform a NatHERS assessment? →
Complete and coordinated plans do not change the technical requirements of the project, but they can reduce avoidable clarification and revision work.
Before requesting a final assessment, it helps to confirm:
An assessment can often begin before every product is selected, but unresolved items may need to be confirmed before the final Certificate is issued.
Whether a revision attracts an additional professional fee depends on the consultant’s agreed scope and the extent of the change.
Changes that may require the assessment to be reviewed include:
A minor clarification may require little work. A substantial redesign can require the thermal model, BASIX inputs, commitments and supporting documentation to be updated.
A BASIX quote should be read alongside the wider costs of obtaining development approval. Unless expressly included, a professional BASIX fee does not generally cover:
Comparing quotes is easier when each consultant clearly identifies the included assessments, certificates, revisions and coordination services rather than presenting one figure without a defined scope.
Project
Plans
Specifications
Frequently Asked Questions
The NSW Planning Portal currently lists a $5 fee for a BASIX Certificate application. This government charge is separate from any professional consultant or NatHERS assessment fee. Portal fees may change, so the current schedule should be checked before lodgement.
The $5 amount is only the NSW Planning Portal fee. Where a consultant prepares the assessment, a separate professional fee applies for reviewing the project, completing the assessment and issuing coordinated documentation.
This depends on the quote. Where NatHERS simulation is required, the proposal should state whether thermal modelling, design review and the NatHERS Assessor Certificate are included or priced separately.
A dual occupancy contains two dwellings and may require separate data, thermal models and design coordination. The scope also depends on whether the dwellings share the same layout, orientation, construction and services.
A preliminary quote can often be prepared from developed concept or approval drawings. The quote may need to be reviewed if the final design, dwelling count or assessment pathway changes substantially.
Some quotes include a defined amount of revision work. Further fees may apply where issued documents need to be updated following substantial changes to the design, glazing, construction or building systems.
Quotes should be compared by scope as well as price. Check whether NatHERS modelling, assessor certificates, design review, revisions, plan coordination and final documentation are included before comparing the total fee.
Related Knowledge
BASIX Certificates and NSW Submission Services →
What Does a BASIX Consultant Do in NSW? →
Fee note: Government charges and professional service fees can change. The $5 NSW Planning Portal BASIX application fee stated in this article was current at the time of review. Confirm current government fees and the project-specific consultant scope before proceeding.
Last reviewed: July 2026.
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