[killermonkeys]

It's a difference in approach that is tied to time: suburban American houses were mostly built after forced air central heating, and in that kind of heating insulation is "less" important (the air mass is mixed and heated thoroughly, not the structure). Europeans still use radiators which means insulation is more important (a radiator next to an outside wall is radiating half of its heat toward the outside wall). But fundamentally it seems like a US apathy toward waste more than an improvement.

SF has historically shoddy construction due to the gold rush, mail order housing bought sight unseen, and a mild climate.

If I built a house in the US I would have it designed by a European.