"Peter" wrote in message
...
If you only examine BTUs per KWH, the oil-filled heaters convert a larger
percentage of total energy to heat than to fan-based heaters because with
the fan, you are using some electricity to blow air rather than using all
of it to generate heat. That said, a fan-based heater may be cheaper to
operate if your specific requirements include rapid heating of a volume of
air (e.g., an entire room) and no prolonged heating after the room has
warmed.

While the fan takes power to blow the air, the motor generates heat due to
the efficiency of it, and the air that is blown around will still make heat
as the air molecules bump into each other. Still 100% of the power is
converted to heat provided there are no doors or windows open for the small
amount of IR and light that may escape.

In any closed room , there is no differance in the conversion to heat. Some
heaters may feel warmer if you are next to them, while the other parts of
the room will stay cold or take much longer to heat up.