Heating tall spaces

Hi, I wonder if anyone has experience/advice in heating tall spaces? My mother has a single story barn conversion with a tall apex roof (maybe 8 m). It is heated with standard double panel convector ‘radiators’.

I feel like (though I haven’t tested it) the heat gradient in the room must be quite marked with the area near the apex of the roof trapping lots of the warm air and there being cooler air near the bottom of the room where all the people are.

Is there any benefit in fitting a ceiling fan or similar to move some of the heated air from the apex of the roof back down towards the inhabited space?

My sister had a small barn that they converted, with a bedroom on top of kitchen & bathroom and full height living room heated by wood burner.
They resorted to a not very pretty length of flexible ducting suspended from near the apex with an extractor fan near the bottom. It did improve things.
Not sure of the practicalities of ensuring no risk of electrocution! Probably had an inline fan fitted above head height where it couldn’t to touched, with more ducting to vent at ground level. I only saw it at the experimental stage.

I haven’t done it myself, but the two recommended technologies are

  • Underfloor heating - so the warmth flows over the occupants.
  • Far Infrared heaters (whcih can be wall or ceiling mounted) to directly warm the occupants, with secondary radiation from the surroundings.

Air recirculation is a good idea, but ideally it should be ducted from the top and gently blown in at floor level rather than just having suspecded fans.

Infrared panels (surface mounted or wire matts plastered into the walls (low voltage DC) or behind plasterboard (AC)), or if your Sister can bear the floor being dug up, the extraction pipe could heat a small set of underfloor channels. A Roman idea…

Conventor radiators should provide sufficient mixing. You will not be talking about a large temperature gradient. Radiative heat transfer will do.

To my knowledge, temperature gradients within rooms are more of an issue of thermal comfort we experience, than the building’s energy efficiency.

@Simon_Hudson I finally remembered where I’d seen the ventilation system that used the cellar… very interesting project, done as part of govt research a while ago and mentioned here

It’s also mentioned in Marion Baeli’s (really good) book