I worked for Energex over a decade ago, in Qld. I used to take a lot of calls involving people's bills increasing or being higher than they thought they should be, that was when the price per kWh didn't change so often. So back then it was things like extra freezers and fridges, dryer use amongst other things.

I am lucky in the past few years I have saved up and paid cash for a new fridge-freezer and new air conditioner, so both of those are very efficient ones. I have a larger capacity fridge which runs at half the cost of my old one; and my air conditioner in my unit is a 3.5kw inverter, so it slowly ramps the power up and down as required. I also run the air con at higher temperatures and dress for that. So on a very humid 35 degree Brisbane day, I might run the air con at 26-28 degrees and just keep that room closed.