How Much Does a BASIX Certificate Cost?

If you've started calling around for BASIX certificate quotes, you've probably noticed a pattern: nobody publishes a price. You fill in a form, wait for a callback, and hope the number that comes back is reasonable.

We think that's backwards. You're already juggling a builder, an architect and a council timeline — the cost of your BASIX certificate shouldn't be a mystery on top of it. So here's a straight answer: what a BASIX certificate costs, what drives the price up or down, and what's not included.

What does a BASIX certificate actually cost?

Pricing depends mainly on the type of project — a single new build is a different job to a duplex. As a general guide:

These are indicative ranges — think of them as a starting point for budgeting, not a fixed quote. Every project is different, and the only way to get an exact figure is to send through your plans. All prices are ex-GST and exclude any government certificate or lodgement fees where applicable.

What actually changes the price?

BASIX pricing isn't arbitrary — a handful of factors consistently drive the cost up or down:

• 1
  Dwelling type — a straightforward single-storey renovation is a simpler assessment than a new double-storey home with multiple zones, glazing types and water fixtures to model.
• 2
  Floor area — larger homes generally take more time to model accurately, which is reflected in the price.
• 3
  Number of dwellings — duplexes, townhouses and multi-dwelling developments are priced per dwelling, though there's often a modest saving when they're assessed together.
• 4
  Turnaround required — standard turnaround is included in the base price; same-day or urgent requests ahead of a DA deadline can carry a premium.
• 5
  Whether NatHERS is bundled in — if your thermal comfort pathway requires a full NatHERS assessment rather than the BASIX prescriptive pathway, that's an additional (and separate) cost.

What's not included in the price?

Is the cheapest quote actually the best value?

Not always. A BASIX certificate that gets rejected by council, or that's inconsistent with what your builder actually constructs, costs you far more in delays than you saved on the assessor's fee. The things worth checking before you choose on price alone:

Is the assessor accredited? Is the turnaround realistic given your DA deadline? Will they tell you upfront if your design won't meet the targets, or just issue whatever comes out of the tool? A cheap certificate that bounces back from council isn't actually cheap once you factor in the delay to your DA.

How to get an accurate quote fast

The quickest way to get a firm number rather than a range is to send through your architectural drawings — floor plan, elevations, window schedule and site plan. With a complete set of plans, we can usually confirm both the price and the turnaround the same day, and issue the certificate itself within 48 hours.

If your plans aren't finalised yet, that's fine too — a rough sketch and a description of the project (new build, renovation, number of storeys) is usually enough for a ballpark figure while you're still budgeting.

The bottom line

A BASIX certificate for a single dwelling new build typically sits in the $350–$550 range, a house with a granny flat around $550–$750, and a duplex around $900–$1,000 — all ex-GST and before any government fees. The exact number depends on your project's size and complexity, but there's no reason it should stay a secret until you've filled in three forms and waited a week.

At Thermal Nest, we'd rather quote you accurately upfront than surprise you later. Send us your plans and we'll get back to you the same day with a clear price and timeline.