Moved house. Anyone know what this is?

[Springchickenonion]

Hi all.
We have moved house and this is in the ceiling for a few rooms upstairs.

I'm assuming some sort of vent. The dial moves and the metal flap inside moved but it's very old and I can't see that it leads to anything.

Any ideas?

My friend had one in her 60s house it was a grid where warm air came out

Vent and the dial opens / shuts it?

Hers was on side wall though not on ceiling

Yes looks like at some time it had a central hot air heating system. Some of estates round here were fitted with this kind of heating

We had vents like that in our house in the 70s. It's where the hot air blew out for the weird hot air heating system.

Ahh OK. Thank you everyone! Mystery solved!

Another vote for warm air vent.

I lived in a house in the 60s with this system, it wasn't very efficient, and the loud clanking of the fan woke the whole household up in the mornings!

You could have AC routed through that

My grandad had these around his 1960's house where it was essentially the heating system. Don't have radiators etc? Could be old remenents

Sometimes can also be air vents for non heated ventilation.
Aunt has an older version of them in her flat and sealed them up, leading to damp on the inside of an outside wall.