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
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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