Central Air Conditioning: Repair or Replace? (2026 cost comparison)
The rule of thumb, from Consumer Reports: don't spend more than 50% of a comparable new unit on fixing the old one. For a central air conditioning, that 50% line is about $4,500–$10,000 AUD — a new unit runs $9,000–$20,000 AUD and typically lasts 9–20 years. If a repair quote lands under that line and the central air conditioning is not yet past its expected life, repair usually wins. Reviewed July 2026.
Repair vs. replace, side by side Estimated
| Cost | Estimated range |
|---|---|
| Typical repair (this central air conditioning, all faults we price) | $132–$7,000 AUD |
| New central air conditioning (unit only) | $9,000–$20,000 AUD |
| The 50% line half a comparable new unit | $4,500–$10,000 AUD |
Repair: min–max of every central air conditioning fault we price (sources on each linked problem page) · New unit: Canstar Blue · Lifespan 9–20 years: Canstar Blue · 50% rule: Quick Air · Reviewed July 2026 · Estimated
Age × repair-cost worksheet Estimated
Find your central air conditioning's age down the side and your repair quote across the top. The cell is the way the 50% rule points — Estimated guidance, not advice.
| Age of unit | Repair < 30% of a new central air conditioningunder $2,700–$6,000 AUD | Repair 30–50%$2,700–$6,000 AUD – $4,500–$10,000 AUD | Repair > 50%over $4,500–$10,000 AUD |
|---|---|---|---|
| Under 7 years first half of typical life | Repair likely | Repair likely | Compare quotes |
| 7–20 years second half, under typical lifespan | Repair likely | Compare quotes | Replace likely |
| Over 20 years at or beyond typical lifespan | Compare quotes | Replace likely | Replace likely |
How this is built: we apply the 50% rule (Quick Air) — spend no more than half a comparable new unit's cost on a repair — with its lifespan corollary (replacement is favored once the unit is past the midpoint of its expected life and the quote tops 50%). Columns are your repair quote as a share of a new central air conditioning ($9,000–$20,000 AUD); the $4,500–$10,000 AUD and $2,700–$6,000 AUD thresholds are just 50% and 30% of that range. Rows use the midpoint of the expected life (about 7 years — halfway through a typical 15-year lifespan) and the top of the sourced 9–20 years range (20 years). Nothing here is a per-unit price or a recommendation — it is a transparent reading of the rule.
The Australian equivalent of this type is ducted refrigerated / ducted reverse-cycle air conditioning. PRICE: new_unit_aud is Canstar Blue's GST-inclusive TOTAL-INSTALLED ('to install in a home') ducted range of $9,000–$20,000, which the same page breaks down by home size (small $9,000–$11,500, medium $12,000–$14,500, large $15,000–$20,000); it is already a supply-and-install figure, so install_delivery_aud is null. LIFESPAN, DISCLOSED LIMITATION: no Australian source found separates ducted from split-system service life — Canstar Blue's figures pool installed air conditioners, and Daikin Australia's warranty deliberately covers one term across the lot ("'5-Year Parts and Labour' warranty applies to all Daikin split, multi-split and ducted air conditioners professionally installed in domestic premises in Australia"). The lifespan range here is therefore the same Australian evidence applied to the ducted type, which is a within-market read-across, NOT a US figure imported into Australia. Treat the ducted lifespan as lower-confidence than the split-system one until a ducted-specific Australian source is found.
One more thing before you replace
A newer central air conditioning can cut energy and water use, which shifts the math on an older unit even when a repair is cheap: ENERGY STAR notes clothes washers over ~10 years and refrigerators over ~15 years are common efficiency-driven replacements.
Energy note: · Reviewed July 2026 · Estimated · Informational only
Price the repair first
Before you decide, get the likely repair figure for the exact fault — each page localizes to your metro:
- Full central air conditioning cost guide
- Not cooling / blowing warm air
- Won't turn on / no power
- Capacitor replacement
- Compressor replacement
- Refrigerant leak repair / recharge
- Frozen evaporator coil
- Clogged condensate drain / leaking water
- Contactor / relay replacement
- Condenser fan motor replacement
- Short cycling (turns on and off)
Estimated ranges — see the methodology for how we build the repair figures and their named sources. This page is informational and is not repair, purchasing, or financial advice.
Reviewed by a Red Seal–certified appliance technician who also holds a Technical Safety BC gas ticket (Gas-C) and an ODS/halocarbon refrigerant ticket (CFC/HCFC/HFC).