The RV500 is almost double the cost of a standard RV water heater and does not have MotorAid.
For many as long as campground electric is free arriving at the camp with a MotorAid heated hotwater tank, running on the electric element most of the time and turning on the gas burner only when showering would make the most economic sense.
Myself I dry camp 6 to 10 days a month and spend around $100 a year on propane, That is in Florida with very little to no use of the propane furnace. Mostly that goes for cooking and running the refridgerator. Even if 1/3 of that is for hot water that would still only be $33 a year. The 20% savings on propane from the RV500 would only be $6.60 year so it would take over 50 years to break even on the additional cost of the RV500 over that of a tank style water heater if you install it yourself and over 100 years if you pay someone else to install it for you. I your existing water heated did not need replacing then the time to recoupe the full cost of the RV500 would be even longer.
Even if you are full time, if your existing water heater does not need replacing you are looking at over $1000 to purchase and install it ($1500?) for a 20% annual return on the hot water portion of your propane bill. If you spend $750 a year on propane and 1/3 of that is for hot water that is only $250 and the 20% savings with the RV500 would be $50 a year so it would take 30 years to break even.
Even with four adults showering consecutivly I have never run out of hot water with the ten gallon water heater installed in my coach.
Maybe if you took 1 to 2 hour long showers and were throwing hundreds of gallons of hot water down the drain every day you could recoup the cost in several years however I believe you would get geater savings/return on your investment by taking shorter showers and installing a more conservative shower head.
You gotta do you own personal math on this one. I can't see the cost justification myself.
2001 Winnebago Adventurer WFG35U