Nichola, it is interesting to see that mine are not the only aircon units connected directly to the mains. When I bought the place, I went around finding out which units, sockets etc were associated with which circuit breakers so that I could isolate appliances if necessary. When away, I switch off all my breakers. If I am going out for the day, I make sure that the automatic settings on the aircon are such that they won't come on ( for example , in summer, I set the units to heat to 21 degrees; as the temperature never drops below that, they never come on automatically).