In article .com,
"Sadly" writes:

With electric heater the energy output is exactly the same as the
energy input.

If you feed, say, 3kW in as electricity you will get exactly 3kW out in
some form of energy. Unlike oil, gas etc. there is no "wasted fuel"
going up a flue.

Well there is, but it happens at the power station before
the energy is delivered to you. You get under 40% of the
energy, and some ~60% goes out the top of the chinmey and
cooling towers.

--
Andrew Gabriel