The formula
For each line item we multiply a quantity by a national unit cost, then apply a quality-grade factor. A regional labour multiplier is applied to the labour portion only; materials are priced nationally. We show the itemised result as a ±22% range.
National unit costs
| Line item | National unit cost | Source |
|---|---|---|
| Outdoor condenser unit | $2,700.00 / m² | hipages.com.au (source for Outdoor condenser unit) |
| Indoor heating unit | $2,000.00 / m² | hipages.com.au (source for Indoor heating unit) |
| Indoor coil / fan-coil unit | $2,250.00 / m² | hipages.com.au (source for Indoor coil / fan-coil unit) |
| Refrigerant lineset & connections | $900.00 / m² | hipages.com.au (source for Refrigerant lineset & connections) |
| Split system (outdoor + indoor heads) | $2,900.00 / m² | hipages.com.au (source for Split system (outdoor + indoor heads)) |
| Ductwork replacement | $30.00 / m² | hipages.com.au (source for Ductwork replacement) |
| Installation labour | $2,200.00 / m² | hipages.com.au (source for Installation labour) |
| Permit, disposal & commissioning | $900.00 / m² | hipages.com.au (source for Permit, disposal & commissioning) |
Regional labour multipliers
Each state's labour multiplier is its private-sector all-industry full-time adult ordinary-time weekly earnings relative to the national private-sector mean, from ABS Average Weekly Earnings (November 2025, Table 14, by state) — used as a proxy for HVAC-mechanic labour because Australia publishes no refrigeration & air-conditioning mechanic (ANZSCO 342111) by-state earnings series in public form, and the private-sector cut strips out the public-service distortion that inflates all-industry figures in the ACT. Multipliers are bounded to a sane range and applied to the labour share of each line item, so materials stay nationally priced while labour tracks local wages.
Data vintage and limitations
Compiled June 2026 from public cost aggregators and government wage data. These are derived estimates, not live contractor quotes. Local prices vary with project complexity, access, and material availability; always confirm with a licensed contractor before budgeting.