How much does it cost to run a split system air conditioner per hour?

A small-to-medium reverse-cycle split typically draws 0.5 to 2.5 kW once it is maintaining temperature. At around 35c/kWh that is roughly 18 to 88 cents an hour, depending on the size of the unit and how hard it is working.

Is ducted air conditioning much more expensive to run than a split?

Usually yes, because ducted systems cool the whole house at once and can draw 4 to 7 kW, or around $1.40 to $2.45 an hour at 35c/kWh. Zoning the system so you only cool occupied rooms narrows the gap considerably.

What temperature should I set for the cheapest cooling?

Around 24 to 26°C is the efficient range for cooling in Australia. Every degree cooler you set the thermostat makes the compressor run harder and longer, so a modest setting with a ceiling fan is the cheapest way to stay comfortable.

Is it cheaper to leave the air conditioner on all day or turn it on when needed?

For most homes it is cheaper to cool only when you are there and need it, especially in a well-sealed room. Leaving a unit running in an empty, poorly insulated house wastes energy holding a temperature no one is using.

Can switching energy plans reduce my air conditioning costs?

It can, because the running cost is your usage multiplied by your rate. If you are on an overpriced plan, every hour of cooling costs more than it should. Comparing your real usage across available plans, as EnergySorted does, shows whether a better rate is available.

Cost to run an air conditioner in Australia

What it really costs to run a split or ducted air conditioner per hour and per season in Australia — and practical ways to bring the running cost down.

The quick numbers: per hour and per season

Air conditioning is one of the biggest swings in an Australian power bill, and the running cost comes down to two things: how much electricity the unit draws, and what you pay per kilowatt-hour. Most homes pay somewhere around 30 to 40 cents per kWh on a general-usage tariff, and that is the number that turns power draw into dollars.

A typical reverse-cycle split system cooling a bedroom or small living area draws around 0.5 to 1.5 kW once it settles into maintaining a temperature. At 35c/kWh that is roughly 18 to 53 cents an hour. A larger living-area split of 1.0 to 2.5 kW lands closer to 35 to 88 cents an hour, and a ducted system cooling the whole house can pull 4 to 7 kW, which is around $1.40 to $2.45 an hour while it works hard.

Over a season those hourly figures add up fast. Run a living-room split four hours a night across a hot summer and you are looking at a modest addition to the bill; run ducted air across the whole house for eight hours a day through a heatwave fortnight and it can dominate a quarterly bill on its own. The lesson is that the size of the space you cool matters more than almost anything else.

What actually drives the cost

The headline capacity on the box (say 7kW cooling) is the heat the unit moves, not the electricity it uses. Reverse-cycle systems are heat pumps, so they deliver several units of cooling for each unit of electricity — that efficiency is measured by the star rating and the seasonal energy efficiency numbers on the label. A higher-star unit doing the same job costs meaningfully less to run.

Beyond the unit itself, the biggest levers are the temperature you set, how well the room is sealed and shaded, and whether you are cooling one room or the whole house. Every degree cooler you set the thermostat in summer makes the compressor work harder for longer. Around 24 to 26°C is the sweet spot most efficiency bodies recommend for cooling.

Cycling matters too. A system that is grossly oversized for a small room short-cycles and never runs efficiently, while an undersized unit runs flat out and still struggles. Matching capacity to the space is what keeps running costs sane.

Seasonal notes

Reverse-cycle air conditioners both cool in summer and heat in winter, and for many homes they are the cheapest way to heat as well — a good heat pump delivers roughly three units of warmth per unit of electricity, which usually beats electric resistance heaters and often beats gas. If you own a reverse-cycle unit, using it for winter heating instead of a plug-in heater is one of the easiest savings available.

Humidity changes the picture in the tropics and along the coast. In humid weather the system spends energy removing moisture as well as heat, so the same set temperature costs more to hold in Brisbane or Darwin than in dry-heat Adelaide. Ceiling fans let you sit comfortably a couple of degrees warmer, which trims the compressor load without any loss of comfort.

How to cut the running cost

Set cooling to 24-26°C rather than chasing a cold house — each degree lower adds noticeably to the bill.
Cool only the rooms you are using; close doors and shut vents to unused rooms on a ducted system.
Run ceiling fans alongside the aircon so you stay comfortable at a warmer setting.
Seal draughts and close blinds against afternoon sun so the unit is not fighting heat gain.
Clean or replace filters each season — a clogged filter makes the system work harder for the same result.
If you are on a time-of-use tariff, pre-cool the house late in the off-peak window rather than through the expensive evening peak.

Where EnergySorted fits

Knowing your air conditioner costs 50 cents an hour only helps if the rate underneath it is fair. Two homes running the same unit for the same hours can pay very different amounts simply because one is on a stale, overpriced plan. EnergySorted costs your actual usage against more than 16,000 plans, with no retailer commissions clouding the ranking, so you can see whether your tariff is the reason summer bills sting.

The Bill Health Score tracks whether your plan is still competitive over time, and if you run heavy cooling in the evenings it can flag whether a time-of-use or off-peak tariff would suit your pattern better than a flat rate. For a roughly $39 a year subscription, that is usually recovered in a single quarter of a hot summer.

General information only, current at the time of writing — not financial advice. Rebate schemes and rules change; always confirm details with your retailer or state government energy site.