Ok I get that some heater are more efficient at heating an area, person heater over space heater etc.
But sometimes
The efficiency gets quoted. And other than losing energy at heat (which seems fine) how else do they lose energy?
In: 30
Energy is required to produce light. When the heating coils glow red, that light is using some of the energy.
From what I understand, it’s a semantics thing.
An electric light heater converts 100% of energy into heat and light, and as those are the byproducts you want, it’s technically 100% efficient.
However, things like – the cable and internal wires have resistance, where energy is lost as heat. You want heat, so that’s fine, but if that resistance didn’t exist you would have more heat in the places you want to have it.
So arguably they’re not 100% efficient too.
Oddly enough, heat pumps can hit 300% efficiency, as in turning one watt hour of electricity into three watt hours of heat. They do that by moving heat instead of generating heat, so a purely radiant electric heater with near 100% efficiency wouldn’t be close to as efficient as a good heat pump.
edit: yes, I realize that this is “technically imprecise”, but this is ELI5, not ELI20, and technical, precise explanations confuse more often than enlighten
Do you have any examples of electric heaters being labelled as less than 100% efficient?
they’re probably referring to sound and light emissions, if you put your head to something that consumes a decent amount of electricity you can usually hear it’s hum, though I wouldn’t recommend going to close to a high voltage electrical line though
They don’t. Usually, tools that use electricity ‘waste’ energy by generating heat, such as a light bulb or LED light where you want to produce as much light as possible with the least amount of heat as a byproduct.
But since heat is what you are looking for, having it ‘waste’ 100% of the energy is what you want, and it’s not difficult to achieve.
Technically, a tiny bit of energy escapes through some infrared light generated by the heat escaping the room, and maybe if you have a fan attached to the heater to blow the air around it doesn’t count as 100% efficient.
Electric heaters are exactly 100% efficient. Lots of people are playing with semantics but forgetting the “efficiency” can only apply to the electricity that is actually consumed by the heater.
Every watt that is consumed by that heater will become heat. Even the red light the coil emits will strike some surface (even the retina of your eye) and then become heat. Any light that leaves the room is a problem in your room, not with the heater.
That said, heat pumps will generally make a room warmer than an electric heater for the same power. It turns out, **it is generally easier to move heat, then to make heat**.
SO what you are telling me is that I should make a “heater”, that is just a cord, that dissipates heat.
Me a 5 year old: ” It’s 100% effecient ”
CFO: “Sir we can’t market this it’s going to catch the things it touches on fire.”
Me: “100% of the energy is heat. It’s 100% efficient.”
Its lack of efficiency comes when compared to other methods of heating.
Its inefficient for the same reason its not effective to heat your kitchen my leaving the stove on. There are other better ways to do the same thing.
The premise of your question is invalid. Electric heaters are possibly the only class of electric devices that are 100% efficient. As in, 100% of the energy it consumes will be turned into heat, eventually. If a product description or a review or something is saying otherwise, it is factually incorrect.
One factor you might want to consider is how well that heater outputs heat in a way that is useful for its intended purpose. A heater that generates a lot of sound and light – which will eventually become heat anyway – may not be as useful if that energy is more likely to escape (through walls, windows etc) than to heat the air in your room and keep you warm. But those “losses” are basically negligible for any enclosed space. A heater that directs it heat onto your body (eg. as infrared radiation) is more useful than one that heats all the air in your room including the air near the ceiling or in some unused corner where your body is not present.
It’s also worth noting that heat pumps can be even more efficient at heating a space than the 100% efficiency of a space heater. Because rather than just generate their own heat, they move (pump) existing ambient heat into a location where it’s more useful (your room).
I recommend [watching this video](https://www.youtube.com/watch?v=V-jmSjy2ArM) and the follow-up videos to understand more.
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