Cheapest way to heat a large room.

BUFF

Happy_Sloth said:

 the radiator which even though it's about 15ft long isn't quite upto the job on it's own.  

Dimensions/design & how old? Where located? May be a good opportunity to update to a more efficient radiator that takes up less wall. 
I had a similar situation with my north-facing main room albeit possibly not quite as large as yours. Had a large single radiator on the back wall but you could feel the temperature gradient across the room to the bay window at the front. Stuck a small radiator into the bay as an addition & it seems to have worked nicely.

markin

The moldings can be copied if you have the budget, i don't know the cost of that. You could also go for underfloor heating clipped to the under side. Tanking and insulating the cellar would also solve the cold floor.

chris1973

Invite yourselves around to the homes of your guests on some of those Saturdays!.