I'm almost 70 and probably will only need one more water heater. There are two of us in our house and we currently have a 65 gallon natural gas unit that's 18 years old. I considered going tankless, but I doubt the extra costs in converting to larger gas pipe plus the cost of the unit would make sense. I was just going to buy a 75-80 gallon unit since the 65 barely allows my large jacuzzi tub to fill. A gas unit of that size runs around $850. I doubt that my HWH usage is more than around $25 in a cold month. Just today my electric utility sent me an offer to convert to a Rheem heat pump water heater which would cost around the same, except that I'd get wifi control, various sensors, etc. Seems like a good deal, but the real question is whether there would be any savings in making the conversion. FWIW, the unit is in a hugely well ventilated area and I could handle running an extra electrical circuit to the heater. Your thoughts?