BASIX (the Building Sustainability Index) is a NSW Government sustainability assessment that applies to residential building work. It’s part of the NSW planning/approval process and is intended to make new and altered homes use less water and energy, produce fewer greenhouse emissions, and be more thermally comfortable.
BASIX was introduced in 2004, ahead of any sustainability requirements in the BCA, as such NSW has a variation in the BCA for BASIX to apply rather than most parts of BCA Part H6. Reference Building and Whole of Home assessment pathways are not permitted in NSW.
How does it help or What does it do?
- Water: reduces potable water use (e.g., water‑efficient fixtures, rainwater tanks, landscape/irrigation choices).
- Thermal performance / comfort: improves the building envelope and design so the home needs less artificial heating/cooling (e.g., insulation, glazing, shading, orientation).
- Energy: reduces energy use and emissions (e.g., lighting efficiency, hot water systems, heating/cooling, ventilation).
- Materials Index: reports the buildings upfront embodied energy emissions.
The Thermal Comfort section;
- can use the DIY assessment tool, limited in its approach as it can specify the minimum insulation levels according to the BCA and then use glazing to achieve compliance, usually results in building costs higher than the NatHERS pathway
- with Alts & Adds can currently only use the DIY tool
- for new dwellings, refer to a NatHERS Certificate for a more tailored or design specific response which usually results in lower building costs offsetting the cost of the NatHERS Certificate many times over.
A Basix Certificate is required at DA stage for a residential project. BASIX doesn’t use class of building but typically a Class 1, 2 or 4 building requires a certificate when;
- Building a new dwelling (Home, Townhouse, Villa, Granny Flat or Secondary dwelling)
- Carrying out alterations or additions (renovation or reno) to an existing house or apartment, valued over $50,000
- Adding a pool to an existing dwelling, over 40,000 litres
- Building new Class 2 apartments (as simple as shop top housing or as complex as 400 units or apartments)
We were part of the BASIX steering committee prior to the implementation in 2004 and have been doing Basix Certificates for builders, designers, architects and home owners ever since.
So if you would like a licensed builder who is an accredited assessor with 20 plus years of BASIX experience, knowing the real world details on how to how to comply, please “Contact Us”.
Whoever you choose to provide your BASIX Certificate make sure they know what they are doing (ask them a few questions), the amount of times we have been asked to comment on a certificate and see the roof area of two downpipes connected to a 20,000 litre rain water tank or products that are high cost or rarely used specified – Dumb stuff.