RADIATORS
Cast iron radiators were introduced to larger houses in the 19th century as a simpler more effective alternative to coal fires. These days, just one coal fire can be more expensive to run than a well designed central heating system. Radiators do not burn gas so turning them off will not save you money. In fact it will most likely put your fuel cost up because you will get cold draughts in the house. Cold air is heavier than hot, so if an upstairs room is not heated then cold air will pass down the stairs into the warmest room. The best place for a radiator is in the coldest part of the room which is usually under a window.