Many climates require it. May through August in Atlanta it doesn't really make sense to turn the AC off while out of the house (down a few degrees, sure - but

Many climates require it. May through August in Atlanta it doesn't really make sense to turn the AC off while out of the house (down a few degrees, sure - but not off). You're going to either pay for the ac to run normal cycles while you're out, or you're going to pay for the ac to run full blast for an hour at 6pm when you get home to bring the temp from 90+ back down to ~78 (which is still in the peak power rate times for GA power - 2pm to 7pm). The house heats up more and more until it reaches temp equality with the outside. If reaching equilibrium takes longer than you're out of the house... you save basically nothing by turning the system off. It's going to either pump the heat out slowly over the day, or all at once when you get home, and there just isn't much savings to be had. That's not even talking about the condensation and expansion/contraction issues that will damage your home.