Energy Efficiency
BASIX Explained: What Every NSW Home Builder Must Know
BASIX (Building Sustainability Index) is a NSW-specific planning tool that sets minimum sustainability targets for new homes. Here is the practical version.
The three BASIX metrics
- Water: Reduction in mains water use vs 2004 baseline. Met through low-flow fixtures, rainwater tank.
- Energy: Reduction in greenhouse emissions vs baseline. Met through efficient appliances, solar, electrification.
- Thermal Comfort: NATHERS rating measuring how thermally efficient the home is.
How to comply efficiently
- Good orientation (free, big impact).
- Standard insulation packages (cheap).
- Light coloured roof.
- Cross-ventilation paths in main rooms.
- Ceiling fans throughout.
- Rainwater tank plumbed to toilets and laundry.
- Heat pump hot water rather than electric resistance.
- Solar panels (often required at 7 stars).
What it costs
Building to BASIX adds $4,000 to $12,000 to a build compared to non-compliant baseline. Most of that is recouped in energy and water savings within 10 years.
Designing a new home? Want BASIX considered upfront?
We run BASIX at concept so you know your compliance position before contract.
Frequently Asked Questions
Quick Answers
Three things: water use reduction, energy use reduction, and thermal comfort. Each has a target score the home must meet to be issued a BASIX Certificate.
Related but different. BASIX is the overall NSW sustainability framework. NATHERS is a thermal performance rating used as one input to BASIX. A home gets a BASIX Certificate that includes a NATHERS thermal score.
Every new residential build in NSW above $50,000 needs a BASIX Certificate before the Construction Certificate is issued. No CC without BASIX. No building work without CC.
An accredited BASIX assessor or NATHERS thermal performance assessor. Cost: $700 to $1,500 typical for a residential assessment.
No. BASIX targets are minimums. A builder cannot deliver a home that does not achieve BASIX compliance. Costs are unavoidable; the goal is to hit BASIX cheaply through smart design rather than expensive specification.
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