wrote:
On Mon, 21 Nov 2011 10:10:12 -0800 (PST), spamtrap1888
wrote:

On Nov 21, 7:55 am, wrote:
My neighbor was telling me that his oil filled radiator type space
heater is more efficient than the kind with a fan and heating
coils. I told him that there is no difference, that all the
electricity consumed by the heater is converted to heat in the
room. Even the sound made by the fan vibrates the air which heats
it up a little. So if both were operated in a perfectly insulated
room and consumed the same amount of electricity the rooms would
heat up the same amount. Now I'm wondering about real world
situations. Some frequencies of light pass through walls, some
through windows, some both, and some neither. So I suppose the best
heater is one that glows in a frequency range that is completely
absorbed by objects (including people) in the room and reflected by
the walls and windows. Are my asumptions correct? I hope so.
Otherwise I'll need to call my neighbor so he can serve me a little
crow.
Eric

There are two kinds of electric space heaters, convection and
radiant. Convection heaters (attempt to) heat the entire room,
radiant heaters heat objects, including you. The oil filled radiator
is a convection heater, as are the heating coil plus fan heaters.

Comparing convection heaters to convection heaters, there is no
difference in efficiency, 100% of the electrical energy does turn
into heat. The Department of Energy prefers the oil filled units
because their thermal mass makes them a more constant heat source.
Their heating elements cycle less, for what it's worth.

But, radiant heaters should have more apparent efficiency in that
they require less energy to heat just you instead of the entire room
plus you in it.

http://www.energysavers.gov/your_hom.../mytopic=12600

Correct, if you ignore one minor detail. Since a radiant heater warms
you, rather than the air, you will always feel colder on the side away
from the heater.

And, the radiant heat will go right through any uncovered windows in its
radiation path.