How much does it cost to run ducted air conditioning in Australia?

Ducted reverse-cycle air conditioning is one of the biggest single lines on a lot of Australian power bills. So what does it actually cost to run — and is upgrading it worth it?

The short answer

A typical ducted reverse-cycle system costs a home about $600–1,200 a year to run. The whole-of-market range is wider — roughly $300 to nearly $2,000 — depending on the size of your home, your climate zone, your tariff and how much you actually use it.

What drives the number

Three things move your running cost more than anything else:

• How much you heat and cool. Running the whole house when you’re only using one room is the most expensive habit there is.
• Whether the system is zoned. A modern inverter system with zone control uses about 30–50% less energy than an older or unzoned one.
• Your tariff. At a typical AU rate of around 36c/kWh, every hour of full-house running adds up fast.

Is it worth replacing for efficiency?

Here’s where we’ll be honest with you. Upgrading an old ducted system to a modern zoned inverter saves roughly $200–500 a year. But a new ducted system costs $8,000–18,000 installed.

That’s a payback of 20 years or more on energy savings alone — longer than the system will likely last. So the verdict is simple:

Don’t replace a working ducted system just to save energy. It won’t pay back. The smart move is to choose a modern, well-zoned inverter system when you’re replacing it anyway — at end of life, when you’re spending the money regardless.

What to do instead (for free)

Before you spend a cent:

• Zone your usage, not just your system — close doors, heat and cool the rooms you’re in.
• Set sensible temperatures — every degree of extra heating or cooling adds cost.
• Service the system — a clogged filter makes it work harder for the same comfort.

These cost nothing and trim the bill today. The big spend only makes sense at replacement.

Figures use the sourced assumptions from the Decode Energy Home Energy Saving Guide (AU 2026 edition). Your numbers will vary with home size, climate and tariff.