On Sat, 14 Apr 2012 12:38:06 +0100, "Dave Plowman (News)"
wrote:

In article ,
wrote:
They were a feature of every kitchen I knew as a kid.

And people just took it for granted that windows would run with
condensation and the only reason mould didn't grow in the corners of
every room was the draught whistling through the house.

Cooking in that kitchen would also produce vast quantities of water
vapour. Then as now. If you don't ventilate for that you'll get
condensation.

Yes, but the majority of inhabitants of said houses were just ignorant
of the basic principles of that. Most still are, of course, but many
more than before have some sort of clue.