Calculate cooling running costs

Last updated: 9 July 2021

The tables below compare approximate annual running costs for various types of cooling systems for a range of room sizes.

* Approximate energy costs per year, rounded to nearest $5. Based an average existing (pre-2005) 2 Star house in a Melbourne climate, cooling all day on the weekend, and in the morning (midnight to 8am) and evenings (5pm to midnight) on weekdays when internal temperatures are high. Based on an electricity tariff of 31.9c/kWh. This is based on a typical Melbourne peak tariff, but does not include any pay on time discount. Note that the evaporative coolers will also use water, and the cost of the water is not included in this table. Actual costs for your house will depend on the area cooled, how long you run the cooling for, your thermostat settings, how well insulated and shaded the house is, your energy tariffs and your local climate. To estimate the running cost for a cold climate (e.g. Ballarat) multiply these figures by 0.85, and for a warm climate (e.g. Mildura) multiply these figures by 3.2. To estimate the running cost for a 5 Star house located in Melbourne, multiply these figures by 0.95, and for a 6 Star house multiply these figures by 0.85.

** GHG = Greenhouse Gas coefficient used is 1.18 kilograms of carbon dioxide equivalent emissions per kilowatt hour.

*** The figures for "zoned" operation assume that cooling in the bedroom areas is switched off during the day (8am to 5pm) and is only operated in the living rooms from 6am to 10pm when the house is occupied, e.g. on the weekends. On workdays, it is assumed that the cooling in the living rooms is only operated from 6am to 8am in the morning and from 5pm to 11pm at night. Other zoning arrangements are possible, and would change the saving achieved by zoning.

Room/space cooling

Small room (12 square metres)

Cooler type Energy star rating Annual energy cost* Annual GHG emissions (kg)**
Portable or ceiling fan N/A $5 15
Portable evaporative cooler N/A $5 20
Split system air conditioner 2.5 stars $35 160
Split system air conditioner 6 stars $10 45

Medium room (30 square metres)

Cooler type Energy star rating Annual energy cost* Annual GHG emissions (kg)**
Portable or ceiling fan N/A $10 35
Split system air conditioner 2.5 stars $50 230
Split system air conditioner 5 stars $20 95

Large area (60 square metres)

Cooler type Energy star rating Annual energy cost* Annual GHG emissions (kg)**
Portable or ceiling fan N/A $15 70
Split system air conditioner 2 stars $75 355
Split system air conditioner 3.5 stars $45 210

Central cooling

Small house (100 square metres)

Cooler type Energy star rating Annual energy cost* Annual GHG emissions (kg)**
Ducted refrigerative air conditioning – not zoned 1.5 stars $195 925
Ducted refrigerative air conditioning – not zoned 3.5 stars $80 380
Ducted refrigerative air conditioning – zoned*** 1.5 stars $180 870
Ducted refrigerative air conditioning – zoned*** 3.5 stars $70 335
Ducted evaporative cooling Standard $45 205
Ducted evaporative cooling Inverter $35 170
Ceiling fans N/A $25 115

Medium house (160 square metres)

Cooler type Energy star rating Annual energy cost* Annual GHG emissions (kg)**
Ducted refrigerative air conditioning – not zoned 1.5 stars $255 1210
Ducted refrigerative air conditioning – not zoned 3.5 stars $125 595
Ducted refrigerative air conditioning – zoned*** 1.5 stars $235 1120
Ducted refrigerative air conditioning – zoned*** 3.5 stars $110 525
Ducted evaporative cooling Standard $65 295
Ducted evaporative cooling Inverter $50 235
Ceiling fans N/A $40 180

Large house (220 square metres)

Cooler type Energy star rating Annual energy cost* Annual GHG emissions (kg)**
Ducted refrigerative air conditioning – not zoned 1.5 stars $315 1495
Ducted refrigerative air conditioning – not zoned 3.5 stars $170 805
Ducted refrigerative air conditioning – zoned*** 1.5 stars $285 1370
Ducted refrigerative air conditioning – zoned*** 3.5 stars $150 710
Ducted evaporative cooling Standard $80 385
Ducted evaporative cooling Inverter $65 305
Ceiling fans N/A $55 250

Use your cooling system efficiently

Remember, regardless of the type of air conditioner you have, you can reduce your cooling costs and still be comfortable if you operate and maintain your cooling system wisely.

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