BASIX Certificate
NSW BASIX certificates for new dwellings, alterations, additions and granny flats - covering energy, thermal comfort and water, ready for DA, CDC or your construction certificate.
BASIX (the Building Sustainability Index) is mandatory for residential development in New South Wales. Every BASIX Certificate must demonstrate that your project meets the state’s targets for energy, thermal comfort and water. We prepare your certificate, optimise the commitments so they are practical to build, and make sure the documentation aligns with your plans so there are no surprises at certification.
What BASIX assesses
BASIX scores three areas: energy (greenhouse gas reduction via efficient fixtures, appliances and design), thermal comfort (usually demonstrated through a NatHERS assessment), and water (reduced potable water use through fittings, rainwater tanks and landscaping).
Which projects need BASIX
You need a BASIX Certificate for new homes, dual occupancies, townhouses and apartments, swimming pools and spas over 40,000 litres, and most alterations and additions with an estimated cost at or above the relevant threshold. It applies whether you lodge through a DA or the CDC (complying development) pathway.
What’s included
- BASIX Certificate covering energy, thermal comfort & water
- Coordination with your NatHERS thermal assessment
- Commitments optimised to be practical and low-cost to build
- Certificate referenced correctly to your plans
- Guidance on the fixtures & specifications required on site
- Support if your certifier raises queries
Prepared through the NSW Planning Portal BASIX tool under the Environmental Planning and Assessment Act 1979 and the State Environmental Planning Policy (Sustainable Buildings) 2022.
The process
How it works
Send your plans & details
Provide plans plus site, landscaping and fixture information.
We optimise commitments
We balance the energy, water and thermal targets to the lowest-cost compliant outcome.
Review together
We confirm the commitments suit your build and budget.
Certificate issued
You receive a lodgement-ready BASIX Certificate in 3-4 days.
FAQ
BASIX Certificate - your questions answered
Yes. A BASIX Certificate is required for virtually all residential development in NSW, including new dwellings, additions over the cost threshold, and pools over 40,000 litres - for both DA and CDC pathways.
Price depends on the dwelling type and complexity. Single dwellings are quoted at a flat fee; multi-dwelling and mixed-use projects are quoted per project. Send your plans for a fast, fixed quote.
Often, yes. The thermal comfort part of BASIX is most reliably met with a NatHERS assessment, which we can prepare at the same time so the documents are fully aligned.
A BASIX Certificate is valid for 3 months from issue for lodgement purposes. If your application isn’t lodged in time, the certificate can be re-issued.
Yes. If the design or fixtures change we update the certificate so it continues to match what is being built.
Ready to get started?
Send us your plans and we’ll return approval-ready documentation in 3-4 days - with 24-hour express available.