What an air conditioner costs to run in 2026

How much does it cost to run an air conditioner per hour?

The number on the box is cooling capacity, not power draw. A 7.1 kW split moves 7.1 kW of heat. It does that using a fraction of the electricity, because it is a heat pump. The federal energy.gov.au guide puts reverse cycle air conditioners on the Australian market at 300% to 600% efficient, which means every kilowatt of electricity moves three to six kilowatts of heat.

So the working is two steps. Divide the capacity by the efficiency to get the electricity drawn at full output. Then allow for the fact that an inverter throttles back once the room is at temperature. Our running cost calculator assumes a typical modern inverter at 4 kW of cooling per kW of electricity, running at an average of 65% of its rated output across an hour. Multiply the result by your electricity rate.

Worked example: a 7.1 kW split. 7.1 ÷ 4 × 0.65 = about 1.15 kW drawn in an average hour. At 33 cents per kWh that is about 38 cents an hour.

What electricity rate should I use? 2026–27 default offer prices

Your own bill is the right number. It shows your usage rate in cents per kWh, and if you are on time-of-use it shows a separate peak rate. If you do not have a bill handy, the regulated default offers are a fair ceiling. Most market offers come in below them.

The peak column matters more than people think. Air conditioning is an afternoon and early evening load, and most time-of-use peaks run from late afternoon to 9 pm. If you are on time-of-use, the same hour of cooling can cost nearly twice as much at 6 pm as it does at 1 pm.

How much does it cost to run a 7kW split system per hour?

About 32 to 48 cents in an average running hour at 2026 flat rates of 28 to 42 cents per kWh. On time-of-use in the evening peak it can reach about 69 cents.

Flat out on a 40 degree afternoon, a 7 kW class unit draws roughly a quarter to a third of its capacity, around 1.8 to 2.4 kW. At 28 to 42 cents that is about 50 cents to $1 an hour for the first hour or so while it pulls the room down. Then the inverter backs off.

Over a day it adds up to a few dollars, not tens. Six hours on a hot afternoon at 33 cents is about $2.30. Ninety days of that over summer is about $205. If those numbers look high for your house, the fix is usually the house: shade the west glass, seal the gaps, check the ceiling insulation. If the unit itself is old or struggling, get up to three local quotes for a modern inverter and compare the running cost.

Ducted air conditioning running costs

A 14 kW whole-home ducted system costs about 64 to 96 cents in an average running hour with every zone open, at 28 to 42 cents per kWh. That is two to three living-room splits' worth.

Ducted is less efficient per unit of cooling than wall splits. energy.gov.au says so plainly: ducted systems use a larger fan and lose energy through the ductwork, which makes them more expensive to run. They are still cheaper to run than gas ducted heating, which is why Victoria pays people to switch. See the Victorian rebate page for that.

Zoning is what closes the gap. With the bedrooms shut off in the afternoon, the system only has to meet the living-zone load and the inverter throttles down to suit. Run one or two zones and the hourly cost lands much closer to a big split. Run the whole house for the dog and it does not.

• Ask for at least a living zone and a bedroom zone. Four zones is common for a four bedroom home.
• Ask where the thermostat or return-air sensor goes. A hallway sensor reads the hallway.
• Ask for the duct insulation rating on the quote. Uninsulated or crushed ducts in a 60 degree roof waste the cooling before it reaches the room.

Which is cheaper to run, ducted or split? Per room, a split is cheaper. For a whole house that you actually use all of, a well-zoned ducted system is competitive with four or five splits, and it is quieter inside. Our ducted cost guide covers the buying side, or get a local ducted quote with a zone plan.

Is it cheaper to run AC all day or turn it on and off?

If you are home, leave it running at a sensible temperature. If you are out for more than a few hours, turn it off or set a timer to start it half an hour before you get back.

The "leave it on all day" advice comes from a real effect. An inverter is most efficient at a steady low speed, and it takes a burst of power to pull a hot room down. But a burst of pull-down is still cheaper than eight hours of holding a cool empty house against a 38 degree day. The unit does not care whether anyone is in the room.

The exception is time-of-use. If your peak starts at 3 or 4 pm, cooling the house in the early afternoon on cheaper power and then letting it coast through the peak can beat switching on at 5 pm into the dearest rate of the day. The same logic applies to solar, below.

At night, sleep mode is the cheap win. It lets the set temperature drift up a degree or two after you fall asleep and caps the fan. Overnight rates on time-of-use are usually the lowest of the day as well. For the settings themselves see the best temperature for your air conditioner.

Running your air conditioner on solar

Running the aircon while your panels are producing is the cheapest cooling you will get. Every kWh the unit uses from your own roof is a kWh you did not buy at 28 to 42 cents, and feed-in tariffs for exported solar are usually a small fraction of that.

A 3.5 kW split drawing about 0.6 kW in a typical hour is well inside what a normal household solar system makes on a summer afternoon. A 7.1 kW unit at 1.2 kW usually is too. Whole-home ducted at 2 to 3.5 kW can eat most of a small system's output, which is another argument for zoning.

The practical move is to pre-cool. Switch on around midday while the sun is high, get the house to temperature, and let the thermal mass carry you into the late afternoon when solar output drops and peak rates start.

Something new for 2026–27: in NSW, south-east Queensland and South Australia, retailers must offer a Solar Sharer default tariff with a three-hour free-usage window, 11 am to 2 pm in NSW and south-east Queensland and 12 pm to 3 pm in SA, capped at 24 kWh. For a household that can pre-cool in that window it is worth a look, though its peak rates are higher than the standard time-of-use offer, so check your whole usage pattern first.

What is the most energy efficient air conditioner? Star ratings explained

The most energy efficient type for most homes is a wall-mounted inverter split, sized correctly, with a high star rating for your climate zone. Ducted systems are less efficient per unit of cooling, and portable units are the worst of all. energy.gov.au notes that portable air conditioners carry a zero-star rating.

Non-ducted air conditioners sold in Australia carry the Zoned Energy Rating Label. It gives a star rating from 1 to 10 for three climate zones (hot, average and cold), separately for cooling and heating, plus the estimated annual energy use in kWh for each zone. Use the stars for your zone, not the best number on the label. A unit can be excellent at cooling in the hot zone and ordinary at heating in the cold one.

To turn a label into dollars, the Energy Rating site gives the formula: annual kWh on the label × your rate. If one 7 kW model's label shows 300 kWh a year less than another for your zone, at 33 cents that is about $100 a year, or about $1,000 over a 10 year life. That is often more than the price difference. Brand still matters for service and parts; see the brand guides and our best split systems page. An installer quoting two models can show you both labels, so get up to three local quotes and ask.

Reverse cycle heating costs, and why it beats a plug-in heater

Heating is where reverse cycle quietly wins. A plug-in electric heater turns one kWh of electricity into one kWh of heat. A reverse cycle unit at 300% to 600% efficiency turns that same kWh into three to six. That is why the calculator says reverse cycle typically costs about a third of what a plug-in heater does for the same warmth.

Using the calculator's method, a 3.5 kW split heating a lounge for six hours a day at 33 cents costs about $1.13 a day, or roughly $113 over a 100 day winter. The same room on a 2.4 kW fan heater running flat out is closer to $4.75 a day. In the cold climate zone, where the label assumes 2,660 heating hours a year, the heating stars on the label matter more than the cooling ones.

How to cut your air conditioning running costs

• Set 25 to 27°C for cooling and 18 to 20°C for heating, the ranges energy.gov.au recommends. Each extra degree adds 5 to 10% to the energy used.
• Close doors to rooms you are not cooling. A split sized for 30 m² will struggle with 60.
• Shade west-facing glass from outside. External blinds or awnings stop heat before it gets in; internal curtains only slow it.
• Clean the indoor filters every few weeks in summer. A clogged filter makes the fan and compressor work harder for the same result.
• Use a ceiling or pedestal fan with the aircon. energy.gov.au puts a fan at around 2 to 3 cents an hour, and moving air lets you set the aircon a degree or two warmer.
• Get the size right. An oversized unit short-cycles; an undersized one runs flat out. The size calculator takes a minute.

If your running costs are high and the unit is old, the numbers on a new efficient unit, plus any state discount, can make replacement pay. Check the rebate on your postcode and compare three licensed installers' prices.