A:Answer If the thermostat is set at 73 and I am warm, I can turn the thermostat to 72 and it kicks on. So I would say 1 degree difference. I have never stood there and watched it but I would assume, based on my experience, that if you have it set to 72 then the AC is going to kick on at 73. It will run the compressor till it reaches 72 then turn the compressor off and it will run the fan for several more mins blowing all the cool air out of the system. Which keeps it cooler and saves money.