I can't give you hard stats, but in Hungary in the 80s (i.e. socialist times) people were building their own houses in the villages (i.e. with the help from extended family only hiring tradesman when you don't have that trade in family) so there was little reason to cut corners. It also avoided the cookie cutter look of American suburbs. These are brick houses, so they're quite sturdy, and could be modernized by adding external insulation. Most of these houses were built with double glazed windows to begin with, so I was pretty surprised that in Britain or Spain it isn't default.