How Much Does It Cost to Run Air Conditioning in Western Australia?
Hourly, monthly and yearly cooling costs at WA's 2026–27 electricity prices, by city, unit size and efficiency, in Australian dollars.
By Mark Curant·Updated
Quick answer
At the Home Plan (A1) tariff usage charge of 33.26¢ per kWh, a typical 3.5 kW (12,000 BTU) inverter split system, which uses about 0.70 kWh of electricity an hour, costs about A$0.23 an hour to run, or A$56 for a month at 8 hours a day. Over a year it comes to about A$140 in Perth, and from A$23 in Albany to A$652 in Karratha. In U.S. terms the price is about 23.15¢/kWh, 26% more than the U.S. average.
Per hour
A$0.23
3.5 kW (12,000 BTU) split, uses 0.70 kWh
Per month
A$56
8 hrs/day × 30 days
Per year, Perth
A$140
600 cooling hours (our estimate)
Your numbers in Western Australia
Your AC now (efficiency 3.0)
A$233/yr
A$0.39/hr
New unit (efficiency 5.0)
A$140/yr
A$0.23/hr
You would save
A$93/yr
A$1,118 over 12 years
Efficiency = kW of cooling per kW of electricity over a season (our assumption for a typical new split is 5.0). Hours start at our estimate for Perth and the price at the Synergy (south-west) and Horizon Power (regional), same uniform tariff usage charge; change them for your home and your bill.
Yearly cost by city
How long the AC runs matters as much as the price of power, and that varies hugely across Western Australia. This table is for one 3.5 kW (12,000 BTU, about 1 ton) inverter split system, which uses about 0.70 kWh of electricity for each hour it runs. Hours per year is our estimate of how long it runs at full power in each city's climate. Cost per year is those hours × 0.70 kWh × 33.26¢.
| City | Hours the AC runs per year | Cost per year, 3.5 kW split | Cost per year, portable unit (same hours) |
|---|---|---|---|
| Karratha | 2,800 | A$652 | A$931 |
| Broome | 2,600 | A$605 | A$865 |
| Kalgoorlie | 1,000 | A$233 | A$333 |
| Geraldton | 800 | A$186 | A$266 |
| Perth | 600 | A$140 | A$200 |
| Bunbury | 350 | A$81 | A$116 |
| Albany | 100 | A$23 | A$33 |
Cooling hours are our estimate of full-load hours for each city's climate, for one unit in the main living area. A home cooling several rooms, or with a ducted system, uses more. The portable column assumes a typical unit drawing about 1 kW.
The price used here
What this table shows
- Usage charge: what each kWh costs on the flat (single-rate) tariff under the Home Plan (A1) tariff, July 1, 2026 to June 30, 2027, GST included. This is what running the air conditioner adds to the bill.
- Daily supply charge: a fixed amount for every day of the bill, whether the AC runs or not, so it isn't part of the running costs on this page.
- Cost per hour: one 3.5 kW (12,000 BTU) split running for an hour at full power (0.70 kWh × the usage charge).
| Network | Area covered | Usage charge per kWh | Daily supply charge | Cost per hour of ACone 3.5 kW split |
|---|---|---|---|---|
| Synergy (south-west) and Horizon Power (regional), same uniform tariff | the whole state: Perth and the south-west on Synergy, the Pilbara, Kimberley and other regional towns on Horizon Power | 33.26¢ | A$1.19 a day | A$0.23 |
Cost by unit size
Split systems in Australia are sold by how much cooling they put out, in kW (the BTU size is in brackets). A bigger unit cools a bigger space but uses more electricity. All at a seasonal efficiency of 5.0 (our assumption for a typical new inverter split) and 33.26¢/kWh:
| Unit size (cooling output) | Typical use | Cost per hour of running | Cost per month (8 hours a day) | Cost per year in Perth (600 hours) |
|---|---|---|---|---|
| 2.5 kW (9,000 BTU) | bedroom or study | A$0.17 | A$40 | A$100 |
| 3.5 kW (12,000 BTU) | large bedroom or small living room | A$0.23 | A$56 | A$140 |
| 5 kW (18,000 BTU) | living room | A$0.33 | A$80 | A$200 |
| 7.1 kW (24,000 BTU) | large or open-plan living area | A$0.47 | A$113 | A$283 |
| 14 kW ducted | whole home | A$1.33 | A$319 | A$798 |
| Portable | one room, no installation | A$0.33 | A$80 | A$200 |
The ducted row assumes the whole system runs at full power for the same hours, at an efficiency of 3.5 (ducts lose some cooling). Zoning, or closing off unused rooms, cuts that cost a lot.
What a more efficient unit saves
Seasonal efficiency is how much cooling a unit delivers for each kW of electricity over a whole season. The higher it is, the less electricity it needs for the same cooling. Yearly cost of one 3.5 kW (12,000 BTU) unit in Perth (600 hours a year):
| Seasonal efficiency | What it's like | Electricity per hour | Cost per year | Saved per year vs an old 3.0 unit |
|---|---|---|---|---|
| 3.0 | old fixed-speed unit (pre-2010s) | 1.17 kWh | A$233 | — |
| 4.0 | older or basic inverter unit | 0.88 kWh | A$175 | A$58 |
| 5.0 | typical new inverter split | 0.70 kWh | A$140 | A$93 |
| 6.0 | efficient model | 0.58 kWh | A$116 | A$116 |
| 7.0 | top models | 0.50 kWh | A$100 | A$133 |
Use the zoned energy rating label
Australian air conditioners carry a zoned energy rating label with separate star ratings, and an estimated yearly energy use, for the hot, average and cold climate zones shown on its map. To compare models, look at the cooling and heating figures for your zone: yearly kWh × 33.26¢ is a quick estimate of that model's running cost.
What to know about electricity prices in Western Australia
Western Australia isn't part of the national electricity market. Households in Perth and the south-west buy from the government-owned retailer Synergy, and the state government sets the residential tariff each year. The same tariff applies in Horizon Power's regional towns, so a kilowatt-hour costs the same in Broome as in Perth, even though supplying it costs far more.
That makes WA the clearest example of climate driving the bill: at the same price, a home in Karratha can spend over four times as much cooling as one in Perth, and almost 30 times as much as one in Albany.
Synergy also offers time-of-use plans (such as Midday Saver) with cheap power in the middle of the day. Running the AC while the sun is up and the house is warming, rather than in the evening peak, suits those plans and homes with rooftop solar.
Cutting the cost
- Set the thermostat to 25–26°C rather than 21°C, and run a ceiling fan with it.
- Close blinds and curtains on sunny windows before the heat builds, especially west-facing ones.
- With rooftop solar, cool the house in the middle of the day and let it coast into the evening peak.
- Cool the rooms you're using, with doors closed, rather than the whole house.
- Clean the indoor unit's filters every few weeks in summer.
- Compare your plan with the default offer: a cheaper market offer saves on every kWh.
How Western Australia compares
SA
41.91¢/kWh
Adelaide · ≈ 29.17¢ US
ACT
36.95¢/kWh
Canberra · ≈ 25.72¢ US
NSW
33.14¢/kWh
Sydney · ≈ 23.06¢ US
NT
31.68¢/kWh
Darwin · ≈ 22.05¢ US
QLD
27.97¢/kWh
Brisbane · ≈ 19.47¢ US
TAS
27.95¢/kWh
Hobart · ≈ 19.46¢ US
VIC
25.96¢/kWh
Melbourne · ≈ 18.07¢ US
Western Australia (Perth): ≈ 23.15¢ US/kWh. U.S. average: 18.31¢/kWh (July 2026). See costs in every U.S. state.
Frequently asked questions
How much does it cost to run air conditioning per hour in Western Australia?
About A$0.23 an hour in Perth for a typical 3.5 kW (12,000 BTU) inverter split system, which uses about 0.70 kWh of electricity an hour, at the 33.26¢/kWh usage charge. A 7.1 kW unit for a large living area costs about A$0.47 an hour, a 14 kW ducted system about A$1.33, and a portable air conditioner about A$0.33.
How much does air conditioning add to a quarterly bill in Western Australia?
Running a 3.5 kW split 8 hours a day uses about 510 kWh over a 91-day quarter, or about A$170 at 33.26¢/kWh. Over a whole year in Perth, at our estimate of 600 cooling hours, it comes to about A$140. The daily supply charge is on the bill whether the AC runs or not.
Is a reverse-cycle split cheaper to run than a portable air conditioner?
Yes, by a wide margin. A portable unit draws about 1 kW and cools less well, partly because its exhaust hose pulls warm outside air back into the room. A 3.5 kW split at a seasonal efficiency of 5.0 draws about 0.70 kW on average while putting out more cooling than a typical portable (about 2.6 kW), so for the same amount of cooling it uses about half the electricity.
How we calculated this
Electricity used (kWh) = cooling capacity (kW) ÷ seasonal efficiency × hours. Cost = kWh × usage charge. Prices: WA Government residential tariff from July 1, 2026, as published by Horizon Power (A2 standard residential, the same rates as Synergy's Home Plan A1). U.S. cents use A$1 = $0.696 (October 2026). Cooling hours are our estimate for each city. To check your own price, look for the usage (or "peak"/"anytime") rate per kWh on your bill.