I too question how good the tankless RV-500 unit is for the folowing reasons:
It is awfully small, most tankless home water heaters such as the Aquastar125 are almost 3 times the size and the Aquastar125 is rated for one use at a time, one shower, one load of wash etc. That said, I am considering a larger model for my house.
The Precisiontemp website has specs for the RV-500 that say:
" there is an 85 degree rise per gallon per minute."
"at 2 GPM of water 20lbs of propane will produce over 940 gallons of hot water"
I cant really find any more information than this on their site or anywhere on the web.
What I am wondering is what is the temperature rise at 2GPM? I doubt its 85 degrees, and how hot is the "Hot Water" in the second quote above
The Aquastar125 has a 125,000 BTU input and has and does 2GPM @ 90 degree rise and 2.4 @75 degree rise
The RV-500, as stated above, does an 85 degree rise per gallon per minute. but it has a 53,000 BTU input
Sooooooo... comparing the Aquastar home unit which is designed for one use at a time (one use being a 2.5gpm use) My guess would be, based on the Precisiontemp specs (or lack thereof) that the RV-500 would be able to generate less than half that. Now 2.5GPM could be considered a lot for an RV shower, and maybe... maaybe at a 40 degree rise the RV-500 could do 2 or 2.5 GPM, but I think if you wake up on a chilly morning and wanna take a hot shower and have a 35 to 45 degree inlet water temp, which is not unusual in many parts of the country.... your shower is gonna be 75-85 degrees, which I guess is tolerable -but its not hot. Maybe the RV-500 is better than that, maybe worse, Im just sceptical when the manufacturer doesn't list the rise over a variety of flows, or at least at the flow which is most important- the shower.
The RV-500 is costly at over $800 and you must also consider your application. If there is a waste and water hookup, maybe the RV-500 would be a better option, the hot..err.... warm shower would be continuous, but if you have to worry about your grey tank filing up, or running out of fresh water when boondocking you arent gonna stand there with the water running constantly for 20 minutes taking a shower. In that situation woudn't you rather have your short spurts of shower water much hotter thant 80-ish? Especially if the tank style water heater costs much less?
-now if you ran 2 RV-500s in series.........