ok - scenario is 2 up ,2 down terraced house . Staircase ,with open bannisters running up from rear of back living room - so that a lot of heat escapes upstairs . Elderly occupant ,very limited mobility using downstairs two rooms as bedsit type set up . Just wanted to ask - best to keep radiators on upstairs and heat whole dwelling ,though upstairs not used or just keep on downstairs ? Keeping warm is the priority ,not saving costs . Any advice ?