It's worth noting that temperature control is only half the equation. In places like Houston, A/C plays a big part in controlling indoor humidity as well(for both comfort purposes and to prevent mildew from growing all over everything).
There's other (read: more efficient) ways to control humidity than using an A/C. Including making buildings more "airtight" so the dampness doesn't leak into the house (as long as you don't open doors/windows too much, of couse).
