Thought Created Water Heater Problems

What I didn't need was another bill but it's always something and the plumber will be changing both (2) thermostats in the hot water heater. One is shot but why play with it just replace both they are the same age. This actually is something created YA I'm sure of it..the water was heat just fine till I began talking to an instillation man about the size wattage needed to be produced for a backup power generator. Looking at one to hook in directly and run on propane since we already have it. Then propane is also more stable at about $3.00 to gas same amount being closer to $4 these days. To go solar your talking big bucks and lots of panels and batteries. Batteries also have a limited life span and are costly. So in end the most economical is propane for me. Theproblem was the Hot Water Tank which takes about 5000 watts so if it's on and there are other things on in the house when the power goes out and the generator kicks in we need a big one...Now the 7000 watt runs about $1500 installed and maintained it's $3200..about right unless I have the gas co. hook in propane and my electrician hook into electric panel and it's more like $2/2500 but would pay for maintenance. I would have to leave the generator off - not on automatic and turn the hot water heat off and only turn it on when all the other things are off. But who want to mess with this ?? the electric co has a timer on my panel (they no longer use) I may be able to set it for use with a generator...

Anyway the object is I realize my thoughts about this were quite in depth and serious so they created a thermostat problem so I know how long the water might stay hot in between turning on the thermostats...for generator compatibility. Creating our mind thought is powerful these days.