BASIX at Occupation Certificate Stage

BASIX remains important at occupation certificate stage because the project needs to be built in accordance with the commitments shown on the BASIX Certificate. The certificate is not only a planning document. It follows the project through approval, construction and final certification.

NSW Planning explains that the BASIX Certificate must be attached to the occupation certificate application. The certifying authority will only issue a final occupation certificate when satisfied that the project has been built as described on the BASIX Certificate. Following the final inspection and before issuing a final occupation certificate, the certifying authority is also required to issue a BASIX completion receipt. NSW Planning Portal

What is the occupation certificate stage?

The occupation certificate stage is the final step in the formal NSW approval and construction process for many projects. NSW Planning describes the final occupation certificate as the last step in the formal DA and construction process. It confirms that the building is suitable for occupation, subject to the relevant approvals and requirements. NSW Planning

For projects with a BASIX Certificate, this stage includes checking that the required sustainability commitments have been delivered. This is why BASIX should be tracked during construction, not only prepared at the beginning of the approval process.

Why BASIX matters before final occupation

A BASIX Certificate lists commitments for water, energy and thermal performance. These commitments may include physical building elements, fixtures, systems and equipment. If those items are not installed or do not match the certificate, the certifier may need more information before issuing the occupation certificate.

This is especially important because some BASIX commitments are easy to overlook during construction. A hot water system may be substituted, a rainwater tank may be moved, solar panels may be reduced, insulation may differ from the specification or window products may be changed during procurement. These changes can affect BASIX compliance at the final stage.

What is a BASIX completion receipt?

A BASIX completion receipt is part of the final BASIX completion process. NSW Planning states that following the final inspection and before issuing a final occupation certificate, the certifying authority is required to issue a BASIX completion receipt. This receipt records that the BASIX completion step has been completed before final occupation is issued. NSW Planning Portal

For project teams, this reinforces the importance of keeping BASIX documentation, product selections, installation evidence and final plans organised. The certifier needs to be able to confirm that the building matches the commitments before completing the final certification process.

What BASIX commitments may be checked?

The exact checks depend on the project and the commitments listed on the BASIX Certificate. Some commitments are visible on site, while others may need product information, installation evidence, specifications, certificates or drawings to confirm.

Common BASIX commitments that may be checked include:

• Rainwater tank size, location and connected uses.
• Water efficient fixtures and fittings.
• Hot water system type and energy source.
• Solar PV system size and installation, where committed.
• Heating, cooling and ventilation systems.
• Window frame, glass type, U value and SHGC commitments.
• Wall, roof, ceiling and floor insulation.
• Shading devices, eaves, awnings or external shading.
• Pool or spa volume, cover, heating, pump and top-up commitments.

Common BASIX problems at occupation certificate stage

BASIX problems at occupation certificate stage often happen because decisions changed during construction but the certificate was not reviewed. These issues can become stressful because they are discovered late, when the owner, builder or developer is trying to complete the project and obtain final certification.

Common issues include:

• The installed hot water system differs from the BASIX Certificate.
• Rainwater tank size, location or connected uses changed.
• Solar PV system size was reduced or not installed.
• Window products do not match the glazing performance commitments.
• Insulation levels were changed during construction.
• Pool or spa equipment differs from the certificate.
• BASIX commitments are not supported by documentation or evidence.
• The project was built from revised plans that were not checked against BASIX.

What happens if the building does not match BASIX?

If the completed building does not match the BASIX Certificate, the certifying authority may require the issue to be resolved before issuing the final occupation certificate. This may involve providing evidence, correcting documentation, undertaking rectification work or amending the BASIX Certificate if the change can still meet the required targets.

Not every difference will have the same consequence. Some changes may be minor and easy to clarify. Others may affect the BASIX targets, NatHERS result or physical commitments on the certificate. The earlier these differences are identified, the easier they are usually to resolve.

How to avoid BASIX issues before occupation certificate

The best way to avoid occupation certificate delays is to track BASIX commitments during construction. The builder, designer, client and certifier should all understand which commitments must be delivered and which product substitutions should be checked before installation.

• Keep the BASIX Certificate with the approved plans and construction documents.
• Check product substitutions before ordering or installation.
• Confirm glazing products match the certificate requirements.
• Record insulation installation and product details.
• Confirm rainwater tank size, connections and location.
• Confirm hot water, heating, cooling and ventilation systems.
• Confirm solar PV, pool and spa commitments where relevant.
• Ask for a BASIX review if anything changes during construction.

When should BASIX be reviewed during construction?

BASIX should be reviewed whenever a construction change affects water, energy or thermal performance. It is better to check before installing a different product than to discover the mismatch at final certification. This is especially important for glazing, insulation, hot water, solar, rainwater, heating, cooling, ventilation, pools and spas.

A mid-construction BASIX check can be useful if the project has changed from the approved drawings, if the builder has proposed substitutions or if there is uncertainty about whether a commitment can still be delivered as originally specified.

How Certified Energy can help

Certified Energy can review BASIX Certificates against completed or near completed NSW residential projects where commitments have changed during construction. Our team can help identify whether the certificate still matches the project, whether evidence may be needed and whether an amendment should be considered before occupation certificate stage.

This is especially useful where hot water systems, glazing, insulation, rainwater tanks, solar panels, heating and cooling systems, ventilation, pools or spas have changed since the original BASIX Certificate was issued.

Related resources

• Complete Guide to BASIX Certificates in NSW
• BASIX Certificate Service
• BASIX at Construction Certificate Stage
• Does My BASIX Certificate Need to Match My Plans?
• Can a BASIX Certificate Be Amended?

Frequently asked questions

Is BASIX checked at occupation certificate stage?

Yes. At occupation certificate stage, the BASIX Certificate must be attached to the application and the certifying authority needs to be satisfied that the project has been built as described on the BASIX Certificate.

What is a BASIX completion receipt?

A BASIX completion receipt is issued by the certifying authority following the final inspection and before issuing a final occupation certificate. It confirms that the BASIX completion process has been recorded.

What BASIX items are checked before occupation certificate?

BASIX items that may be checked include insulation, glazing, rainwater tanks, hot water systems, solar panels, water fixtures, heating, cooling, ventilation, pools, spas and any other commitments listed on the BASIX Certificate.

What happens if the building does not match the BASIX Certificate?

If the building does not match the BASIX Certificate, the certifying authority may require clarification, evidence, rectification work or an amended BASIX Certificate before issuing the final occupation certificate.