Calculating electricity costs
I'm trying to zero in on a design for a solar system for my 2,000 sq.ft. home that would provide all present and future electric use. I presently use a voyager high efficiency 90,000 btu propane heater that provides dhw as well as the hot water for the radiant floor system that heats the home. The voyager is ten years old and they haven't proved to be the most reliable heater out there though mine ( knock on wood) has been fine since I replaced the motherboard. However, I want to be prepared to make the switch when it does go. The problem is I have no idea how much electricity I will use to provide the hot water for the radiant floor. Even a ballpark figure would be helpful. My thinking is that if I know how much propane I burn every year I can then somehow calculate how much electricity I would need and then I could size my solar panels.
Would it make more sense to separate the two systems and rely on tankless hot water heaters for all dhw? or? If it maters I live in Northern California.
I would greatly appreciate your thoughts.