We live in GA. I have to preface my numbers with: my husband is a cold man, and I'm a skinflint. Also, I'm hot-natured, and prefer to sleep in a room cold enough to hang meat in. 74 in the summer is as low as I will go, wallet-wise, and my husband doesn't freeze. We have a programmable thermostat but over the summer I experimented with keeping it at 74 24 hours a day and it saved money. Color me surprised. In the winter I can only go down to 64 without my husband turning into a popsicle.