RE: The Car and Arctic Monkeys for week 74 of ttt

Well, that is why you have a problem. The idea is that stepoints keep a building between two temperatures and it switches on and off as needed.

If you ask for 21C then it cools(or heats) down till it gets to 21C and then rests. If your windows are closed and you have curtains this will last longer. The moment the temperature inside measures 22C or 20C, the AC should switch on and cool or heat as needed again.