Wow, answers here would be all over the map as usage varies so widely. Certainly don’t run genie on propane to heat water.
Propane has roughly 90,000 BTU per gallon. Water heater will use about 8,500 BTU per hour, furnace about 25,000 (all rough estimates).
Then you also have generator use plus dish washing, etc. And since water heater recovers quickly, we don’t leave it on constantly, just when we use it and furnace obviously is not on continuously either.
Given you are new to this, my guess is you are need to give it a go and see how it works out. At the very least I can’t imagine it will not last a very long time and generator use will be the deciding factor.
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SC