A basic question about electric heaters

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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

 

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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_home/space_heating_cooling/index.cfm/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.

PlainBill

 

[gregz]

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

True.

The only thing, radiant might be considered more efficient because inducing
drafts might make the air feel colder.

Greg

 

[gregz]

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.

PlainBill

I don't know what the efficiency of radiant conversion is, but radiant
heaters give out plenty of heated air also. Some also have fans.

Greg

 

[Bob F]

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.

 

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

Not necessarily. Glass is opaque in the infrared range. However,
they WILL absorb the energy and if single pane will release half the
heat generated outdoors.

PlainBill

 

[Cydrome Leader]

That said, I have not yet seen an oil filled heater more than a few
years old that did not leak to some degree. Not sure what might happen
if the oil level drops to the point that the heater element starts
boiling it.

Neil S.

Are those things full of used chinese motor oil or something else you
don't want to touch or have catch on fire?

 

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Are those things full of used chinese motor oil or something else you
don't want to touch or have catch on fire?

Where do you think they're putting all that pcb tainted oil?

 

[Cydrome Leader]

Where do you think they're putting all that pcb tainted oil?

Ha, I figured they used all that stuff up in foods and to polish rice by
now.

 

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Ha, I figured they used all that stuff up in foods and to polish rice by
now.

Duzzat mean I should avoid brown rice?