GREAT to hear you got it working!
It will maintain hot water at about 155 degrees. The big flame will go out when it reaches that temp and come on whenit drops lower to about 95 degrees.
The house heater/furnace will take the most propane and will use it up fast. A gegular tank will be gone in 3 or 4 nights if you like it really warm.
I'd suggest a safe electric heater that will not overload the circuit breaker.
A 1400 -1600 watt will keep it bearable. Anything larger will blow a trailers circuit breaker if only 15 amp. 1,800 watt is the max you can use before it pops the breaker.
Walmart has a great assortment at reasonable prices.
I used to use one like this in my 5th wheel but mine didn't osolate