[scheme271]

That's true but a 1000W heat pump can get you 3000W of heating. I.e. if you use a given amount of energy to transfer heat from the outside, you effectively get more than 100% (most heat pumps are at 300% efficiency).

[LoveMortuus]

Efficiency can't be higher then 100%, if it could be then you've got a perpetual motion device or in other words, you're creating new energy that didn't exist in the universe before - breaking physics.

Not to mention that heat pump efficiency isn't linear as it depends on the humidity and temperature in which it's operating.

Electric heaters more or less just lose energy in light that they produce, which is quite often negligible.

[BaseballPhysics]

You confusion is a failure to understand what heat pumps are doing.

An electric heater uses 1000W of electricity to increase the energy in an air volume directly.

Heat pumps use 1000W of electricity to transfer energy from one area to another.

In the former case, the energy in the warmed air is entirely from the supply of electricity.

In the latter case, the energy in the warmed air comes from the intake air and the electricity is only used to move that energy around.

So absolutely a heat pump using 1000W of electricity can move 3000W of thermal energy from the hot side to the cold side.

This, by the way, is why you're absolutely right that efficiency is variable, as it depends on the energy gradient between intake and output.

[SigmundA]

>Efficiency can't be higher then 100%, if it could be then you've got a perpetual motion device or in other words, you're creating new energy that didn't exist in the universe before - breaking physics.

Only in a closed system, heat pumps are not a closed system, they take advantage of ambient heat in the environment which brings efficiency above unity if measured as power input vs heat output.

[rightbyte]

It is called appearant efficiency and it can be and usually are greater than 1.