"Martin" wrote in message
...
I can't quite get my head round trying to stop a fire from putting
heat
into a room.
heat into room is a good thing 
Very hot chimneys such that the wallpaper and/or paint peels away into
a
horrible sight is a bad thing 
OK, but isn't there some way of 'deflecting' the heat into the room
rather than sending it up the chimney?