I was thinking of generation losses. That is why I said “at the heater itself”. There was no sense in over complicating things. I mean you could say the same thing about Nat Gas(ect...). There are all kinds of inefficiencies in that system other than the efficiency of the Furnace or Boiler.
Agreed FRiend!
Just having fun with the question.
(Harmonic distortion...) ;-)