Another question here - it's around the whole issue of heating one room versus the whole house . For myself I'm happy to just heat the one room but.....the scenario with my mother is ,in her 90's ,doesn't move around much ,lives alone in what is basically a 2 up ,2 down ,with a back extension kitchen ,never goes up stairs . I have been told to keep rads on upstairs to slow the escape of heat from downstairs ,kind of keep a cushion of hot air especially above the cold kitchen . My aim is NOT to keep her bills down ,but to keep her warm . What do people think ?