[NeedMoreTea]

Forced air was very briefly in in the UK. For a few - maybe as few as five - years around the early or mid 60s forced air was fairly commonly seen in new build houses and the type of small blocks that have 6 or 8 flats. By the seventies no one was putting them in new builds any more, and people were already ripping them out - or sealing up the vents - to go back to just a fire - though without a chimney it would have to be electric or gas, or to put in central heating or storage heat.

You will never find one of those houses still using it. Doesn't matter who built the house, where, when, what make of components or which fuel. Usually electric, but there were quite a few gas. Effectively all have been ripped out now. You might find evidence of ducting when rewiring.

[misnome]

We lived in a house with this under-floor-air system until we moved last year. We inherited it from my mother-in-law a few years previously. She didn't really think of maintenance, and so turns out it was using the original gas heater system.

This was quickly condemned when we got it inspected - it had a crack in the heat exchanger and - these things were apparently only designed to last 25 years. Lasting 50 was pretty impressive/dangerous.

You can get replacement heaters for them, but it's pretty niche, needs to be imported from Europe, and because of the age normally involves dealing with asbestos insulation. It's also apparently virtually impossible to get the venting cleaned, as it's embedded in the flooring (under concrete for the group floor). (Edit: And this caused real problems for Asthma sufferers)

While it worked though it was pretty good, it heated rooms extremely quickly.

[NeedMoreTea]

I'm really surprised - and a little impressed - that one hung on that long. :)

From various encounters over the decades they all seemed to come with feint smell of burnt dust or just dust. By the eighties it was usual to see a radiator in front of or above the old vents, or the vents simply boarded or painted shut.

No idea why it was so comprehensively and quickly rejected despite that brief popularity. Maybe the impossibility of proper cleaning or expense? Though I wonder what they do for cleaning in the US. It's the only approach that hasn't managed to keep some spot in the market even after large declines - like storage heaters or, more surprisingly, even coal have.