Ultimately if the heating element is 4500 watts that is all the energy there is to heat the entire place. Or about 15k BTU. Is that enough?heat pump was first choice, but its too cold here in the winter. I can by top of the line japanese HPWH used 2-3 years old for about 1000 USD each (especially with the current yen to dollar rate). i was originally thinking of getting two to heat the tank, but investigations among the locals, and talking with some members here on the forum put the kibosh on that idea.
1st world problems, I know.
I get the heat pump issues as it still needs to pump the heat out of the structure if space heating.