I do like a cooler environment for sleeping, i.e. 65 F. For the day, I'm more into 70 F, but I probably could manage around 68 if I had to. In summer the thermostat is set at 78 degrees before the a.c. will turn on. What I find strange is when some people to have the a.c. set at a colder temp in summer than they have the heat in winter.