Curious. How did you calculate that ?
Propane is $1.89/gal (from memory). electricity ie $.29/kwh, COP of a Mitsubishi hyper at low temperatures is 1.4 ( although higher at warmer temperatures).
Propane boiler is 92 or 93% efficient, and paid for, although I also use the 82% hanging heater if I’m there in the winter, which I’m not. ( although I can see snow at the top of Mt Lemon here in Tucson since they got 8” up there at 7500’ yesterday.) The building has about 2700 sf of heated shop area, A 48k btu Mitsubishi hyperheat runs $17-20 k installed, according to AI..
That’s probably about right based on what I paid for a much smaller one for the hyper we installed in the house around eight or ten years ago. The payback isn’t there. Plus, I’d have to buy a new water heater since a mini doesn have that capability, so there’s another $1k for an electric.
Just doesn’t pencil out for me.
Here in Az, it’s a different story. Propane, I think is higher, electricity is much cheaper, cop is higher since the minimum temperatures are normally above freezing…yada, yada.