[pjc50]

I think this is itself a "legacy joke"; I would say it was the 80s-90s when door to door double glazing salesmen were rife. The only real objection was the sheer cost of retrofitting it, plus a bit of stiff upper lip about not caring about being cold.

A friend of mine lives in a single-glazed 13-storey 1960s apartment block. It can be quite drafty. There's no way it will ever be refitted and I'd give it a couple of decades until its demolition.

The UK's housing stock is very old on average and some of it is in very poor condition.