Saving money by installing an extra radiator seems a strange thing to do. The reason I'm doing it is to improve comfort through better control and overall supply of heat around the house.
The living room was the main area problem area because it didn't have a radiator even though the room included a large bay window. As the main relaxation area the result of this omission was to rely on heat from the adjacent dining room. However, to do this meant that the dining room was often over heated in order to 'spill heat into the living room. A wasteful situation so the decision was made to install an additional radiator in the living room.
Obviously only time will tell on the net result but I'm optimistic it will result in lower heating demands and greater comfort downstairs.