BASIX can be required whether a residential project in NSW is submitted through a Development Application or a Complying Development Certificate pathway. The certificate itself still addresses water, energy use and thermal performance, but the approval pathway changes who reviews the application, how the documents are lodged and how quickly the project may need to be ready for assessment.
The most important practical point is that the BASIX Certificate should match the plans and specifications submitted with the approval documents. Whether the project is going through council as a DA or through a certifier as a CDC, the BASIX commitments need to be clear, accurate and coordinated with the design before lodgement.
BASIX does not become a different assessment simply because the project is lodged as a DA or CDC. It still covers water, energy and thermal performance. What changes is the approval pathway, the lodgement process and the need to coordinate the certificate with either the council application package or the certifier’s CDC documentation.
A Development Application, often called a DA, is an approval pathway where the proposed development is assessed by council or the relevant consent authority. This pathway is commonly used when a project needs merit assessment, does not fit a fast-track code pathway or requires broader planning review before consent can be granted.
For residential development that requires BASIX, the BASIX Certificate is usually prepared as part of the DA documentation package. The certificate helps demonstrate that the proposed dwelling, alteration, addition or residential development addresses the required sustainability commitments for water, energy use and thermal performance.
A Complying Development Certificate, often called a CDC, is a fast-track approval pathway for development that meets specific planning and building standards. In NSW, complying development is a combined planning and construction approval for straightforward development that can be determined by council or an accredited certifier.
Because a CDC is intended to move quickly when the project meets the required standards, the documentation needs to be well prepared before lodgement. If BASIX is required for the residential project, the certificate should be ready and consistent with the plans submitted to the certifier.
The core BASIX assessment does not change simply because the project is lodged through a DA or CDC. BASIX still reviews water, energy and thermal performance. The project may still need to account for fixtures, hot water, heating and cooling, ventilation, rainwater tanks, glazing, insulation, shading, solar panels and other commitments depending on the scope.
What changes is the approval context. For a DA, the certificate supports the development application package. For a CDC, the certificate supports the certifier’s review of a project that must meet the relevant complying development standards. In both cases, the BASIX Certificate should be prepared before lodgement and should match the submitted drawings and specifications.
The approval pathway matters because it affects the project timeline and the level of documentation readiness needed before lodgement. A CDC is often more time sensitive because it is designed as a faster pathway for straightforward development. If the BASIX Certificate is incomplete, inconsistent or delayed, it may hold up the CDC application.
A DA may allow more time for assessment, but BASIX still needs to be accurate when submitted. If the BASIX commitments do not align with the plans, council, the certifier or the project team may need clarification later. This can create avoidable rework, especially if the design changes after lodgement.
For DA projects, BASIX is generally part of the planning submission. The certificate should reflect the design shown in the architectural drawings and any supporting specifications. This includes the dwelling layout, glazing, floor areas, water commitments, energy systems and thermal comfort assumptions used in the assessment.
DA projects may need BASIX coordination where there are:
For CDC projects, BASIX can be especially important to coordinate early because the application relies on the project meeting set standards. The certifier needs documentation that demonstrates the project is ready for assessment. If the BASIX Certificate is missing, outdated or inconsistent with the plans, the CDC process can be delayed.
CDC projects often benefit from having BASIX prepared after the plans are sufficiently developed but before the application is submitted. This gives the project team a chance to resolve glazing, insulation, rainwater, hot water, solar or thermal comfort issues before they become a certification problem.
Whether the project is going through DA or CDC, the assessor usually needs clear project information before preparing the BASIX Certificate. The most important documents are the current architectural drawings, including the site plan, floor plans, elevations, sections and any available window or construction details.
Useful BASIX documents and details include:
Yes, BASIX can delay lodgement if it is not started early enough or if the required documents are incomplete. The most common delays happen when the plans are still changing, the window details are unclear, the construction assumptions are missing or the project does not initially meet the required thermal comfort outcome.
For CDC projects, this can be particularly frustrating because the pathway is designed to move quickly. For DA projects, the delay may appear less urgent at first, but unresolved BASIX issues can still create rework before lodgement or during later approval stages.
Sometimes a project starts as a possible CDC and later moves to a DA pathway because it does not meet the relevant complying development standards. In that situation, the BASIX Certificate may still be useful, but it should be checked against the final lodgement drawings and the selected approval pathway before submission.
If the design has changed during the pathway review, the BASIX Certificate may need to be updated. Changes to floor area, layout, glazing, roof form, insulation, hot water, rainwater, solar, pool or spa details can all affect the certificate and should be reviewed before the application is lodged.
The safest approach is to prepare BASIX once the plans are developed enough for assessment, but before the project is under pressure to lodge. This gives the designer, client and assessor time to resolve issues before they affect the DA or CDC timeline.
Certified Energy prepares BASIX Certificates for NSW residential projects going through both Development Application and Complying Development Certificate pathways. Our team can review your available plans, confirm the likely BASIX scope and coordinate the certificate with any NatHERS thermal comfort modelling required for the project.
We can also help identify likely documentation gaps before lodgement, including missing glazing details, unclear insulation assumptions, unresolved hot water systems, rainwater tank information or design changes that may affect the BASIX outcome.
Send your available plans to Certified Energy and our team can review the project scope, approval pathway and likely BASIX requirements.
Request a QuoteA BASIX Certificate is commonly required for eligible NSW residential projects submitted through either a Development Application or a Complying Development Certificate pathway. The certificate should be prepared before lodgement and should match the plans and specifications submitted with the application.
The BASIX assessment itself still addresses water, energy and thermal performance. The main difference is the approval pathway. A DA is assessed through council, while a CDC is a fast-track combined planning and construction approval for straightforward development that meets set standards.
For residential CDC projects that require BASIX, the certificate should be obtained before the CDC application is lodged so it can form part of the required documentation reviewed by the certifier.
Yes. BASIX can delay lodgement if the certificate is missing, the plans are incomplete, the thermal comfort pathway is unresolved or the BASIX commitments do not match the application drawings and specifications.