"Dave Plowman (News)" wrote in message
...

The room is warmed by the central heating morning and evening when the
rest of the house is in use. All that's needed is to maintain that
temperature during the day. And all electric heaters are 100% efficient.
Apart from a fan heater where the fan uses extra energy. ;-)

fan heaters are also 100% efficient, all the input energy ends up as heat.