How to use it
Find the input power
It's in the manual or the specifications, in kW. Use input power, not capacity: Mitsubishi Electric says capacity is what the unit delivers, while input power is what it draws from the supply.
Enter your hours
A typical day for you. If you use the unit both ways, run it once for summer and once for winter.
Add your rate, if you want to
Your bill shows it in cents per kilowatt hour. Without it you'll still see the kilowatt hours.
The method behind it
It's the RAA's method: input power in kW times your rate gives an hourly figure, and multiplying by your hours gives the total. The RAA notes this assumes the unit is drawing its maximum the whole time.
Real use is lower. The RAA says a unit switching on and off to hold the temperature uses less on average, and the Energy Rating calculator says air conditioners may run at less than rated capacity. Read the answer as the top of the range.
What changes your real number
The thermostat. The Australian Government's Energy Rating calculator suggests 18 to 20 degrees in winter and 25 to 27 in summer, and says each degree beyond that could add 10% to your electricity bill.
The filters. Daikin says swapping a blocked filter for a clean one can lower energy use by anywhere from 5% to 15%.
The house. CHOICE says a split in a well-insulated, well-sealed house can hold a comfortable temperature at very low power.
What we'd do
Our take
Run it with your own rate and an honest number of hours, then compare two models of the same capacity using their input power. That gap is the part the model choice controls. For comparing models before you buy, the government's Energy Rating calculator also takes your tariff and fills in your climate from your postcode.