How do I find the BASIX certificate for my house?
Written by a registered architect for Dudils.
Search your address on the BASIX lookup: where the council published the certificate with the development application, we show what it says. Otherwise the copy is with whoever approved the house, the council for a development application or the certifier for a complying development certificate, and the builder should have handed one over with the keys.
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What is a BASIX certificate?
A BASIX certificate is the document that shows a new NSW home meets the state's targets for water use, energy use and thermal comfort. BASIX stands for Building Sustainability Index. Every new house needs one before it is approved, and so do alterations and additions costing $50,000 or more and swimming pools of 40,000 litres or more.
The certificate lists the commitments the builder then has to build in: the insulation, the windows, the hot water system, the rainwater tank, the fixtures and any solar panels. Since 1 October 2023 new homes also report a materials index, an estimate of the emissions embodied in the building materials.
Where is the BASIX certificate for a house kept?
It is kept with the approval it was lodged with. For a development application (DA), the council holds it on the DA file, and many councils publish it on their online DA tracker beside the plans. For a complying development certificate (CDC), the certifier who issued it holds it, and those documents are usually not published. A copy should also be in the owner's handover documents from the builder.
How do I get a copy from the council?
Search the council's online DA tracker for the address and open the documents of the approval for the house. The file is usually titled BASIX Certificate, or Stamped BASIX when the council stamped it with the approval. If the documents are not online, ask the council for access under the Government Information (Public Access) Act 2009, known as a GIPA request. Councils handle these as informal requests or formal applications, and a formal application carries a fee.
Why is there no BASIX certificate for my house?
Usually because the house is older than BASIX, or because the certificate was never published. BASIX began for new houses in Sydney on 1 July 2004 and across the rest of NSW on 1 July 2005, so a house approved before then has none.
A house approved as complying development has a certificate, but the certifier holds it and it is rarely online. Ask the certifier named on the complying development certificate, or the council, which receives a copy of the approval documents.
What does a BASIX certificate tell me about my house?
It tells you what the approved design committed to. That covers the insulation R values for the roof, ceiling, walls and floor, the window frames and glass, the hot water system, the heating and cooling, any solar panels and their size, the rainwater tank and what it is plumbed to, and the star ratings of the showers, toilets and taps. Where the thermal comfort was assessed with NatHERS, the certificate also quotes the heating and cooling loads, and the NatHERS guide explains those.
What else do people ask?
Does a BASIX certificate prove the house was built that way?
No. It records the commitments of the approved design. The certifier must be satisfied the commitments were met before issuing the occupation certificate, but a house can be changed later, so check what is there before you rely on it.
Is a BASIX certificate the same as a NatHERS certificate?
No. NatHERS rates only how much heating and cooling the shell of the house needs. BASIX is the NSW approval requirement that covers water, energy and thermal comfort together, and a NatHERS assessment is one way to pass its thermal comfort part. Many NSW houses have both.
Can I find a BASIX certificate by address for free?
Yes, for the councils we have read. Search the address on the BASIX lookup and we show the certificate's facts and every certificate on file for that home, with a free site report for the block.
Where does this information come from?
This guide explains how BASIX and NatHERS work in general. A certificate records the design that was approved, and your home may differ from it. Nothing on this page replaces advice from your certifier, engineer, lawyer or your own designer.