How long would it take the largest room in your house to get from 8C to 15C with regular radiators?

[SpaceNambo]

My room hovers at 8C with this cold. Last night it took about 2.5hrs to get to 15C with the gap under the door wedged with a towel. (I have double glazing). I'm comfortable at 15.

Mines never been that low, but from 14 to 18 it’s about 45 mins

I'd guess no more than an hour after I'd put the heating on. I don't think any part of the house would ever get that much colder than what I think is a comfortable temperature though.

Mine used to take that long because I turned the flow rate on the boiler down. That's fine if your house is well insulated but ours isn't.
Once I realised, and turned the flow back up, it heats up, from 13 to 18 in about 30 mins

I can't get our biggest upstairs room to 15 with just the two radiators, it goes between 11-14°. The big room downstairs with 3 radiators gets toasty very quickly though as it has much lower ceilings.

Winter is really outstaying it's welcome this year 😖