This is a bit away from the "sweet spot," but it's still an acceptable answer. We certainly don't need to cool an entire building when it really isn't all that hot. However, the key to surviving a hot summer lies in acclimating oneself to the warmer temperatures. Going in and out of an air-conditioned room may work against that goal. In any case, we do need to limit our use of air conditioning in accord with the goal of good stewardship of God's gifts. Most of all, we need to remember that air conditioning is a luxury and not normally a necessity.