A radiator's heat output is measured in watts or BTUs, and makers list the output for every size. The output a room needs depends on its size, how many windows and outside walls it has and how well it holds heat.
Solid stone walls and high ceilings, common in older homes around Littleborough, can need more heat than a modern room of the same size. Jaque allows for that when he works out the size, along with how often the room is used.
The usual spot is under a window, where the radiator warms the cold air coming off the glass. If that wall is taken, a tall radiator on another wall can give the same heat from a narrow space. Keeping sofas and long curtains clear of the radiator lets the heat reach the room.
Cast iron radiators are heavy once they are full of water, so they stand on feet and are tied back to the wall. Jaque checks the floor and the wall can take the weight before he fits one.
If a heat pump might go in later, mention it when Jaque quotes. A heat pump runs at lower water temperatures, so it needs larger radiators for the same room, and he can size for that now.
