...tropical places like Maryland, S. Carolina, Louisiana and a few others, which rival Calcutta and Central Africa for unbearable heat and humidity.
Thanks, Bob: Cap'n Kiwi didn't believe me when I warned him about the Eastern half of the U.S.

You are right when you say that most houses here have central heating; I feel obligated to point out, however, that there are areas where people still live in, essentially, shacks. One stove for heat (assuming they can get any fuel for it), and of course no A/C. We, the richest country in the world, still allow people to live like this. Shame on us.