I posted this in the main foru, but realise not everyone ventures there, so I am duplicating it here:
I found this company mentioned on another forum. They sell a sensor to automatically switch off your air con when the room is not being used, ideal for those of us renting out in the summer who have guests that leave the air con on 24/ 7. I have looked into these before, but they had to be wired into the air con unit and it was found that they weren't up to the job. Theses units look to be about the size of a smoke detector and operate by sending a switch off signal to your air con unit, mimicing the signal from your remote control. I have just bought one (be careful of the £8 postage cost!!), to take with me next time I go to Spain to try. They have assured me that if it doesn't work, I can have a refund. I have ordered mine today and they reckon I should have it by Thursday.
I have nothing to do with this company, it is something I thought may be beneficial to others.
Mark