I think that in part, the American reputation for overheating is city folk who aren't accustomed to the idea that there's a natural ebb and flow to nature.  (A time when things turn green, it gets warm. A time when things die, and it gets cold.  To everything turn, turn, turn.  There is a season. Etc.)

This is a big factor, I think.  The younger generations (of which I am still a member, despite my age) have been brought up to pretend that seasons don't exist.  Hot outside?  AC.  Cold?  Heat.  No vegetables in winter?  Fly them in from Chile.  Everything is supposed to be just as comfortable at all times, and no adjustments should be made to the weather at all.

For whatever reason, the majority of new English teachers in my small Japanese city have been from California.  Year after year, a group of young women arrive who believe that it is a birthright to wear flip-flops all year long, and have no proper winter clothing, and no understanding of home heating.  But instead of adjusting to the situation after the first cold snap, they go into winter denial.  They keep doing things the way they always did, keep wearing their same, grossly inadequate clothes, and whatever, because they cannot bring themselves to believe that winter is really cold, and that you have to adapt your behavior to the world around you on occasion.  "Sure, I'm freezing to death, but it will only be for another few months."

The second year, they usually come around.  Or they go home.

It will be a horrible, horrible shock for such people should a real energy crisis demand that the seasons be recognized.