I have the BaseCampCamping 's XCW20 shower system.
I've spent a good year researching a shower system that would work best for my needs. The problems I encountered varied. - Electric heating takes way too much energy
- The heat exchanger method requires you to have your car running, and you are then tied to your car, not to mention its a pain to regulate heat
- The solar shower and shower bag method dont work well late at night, can't double as a kitchen style faucet, and won't work well in truly cold temperatures.
This sytem is entirely self contained, I just attach the propane, and drop the pump into my desired water source.
Then, Select shower head or water faucet, set my temperature, and press pump.
Instantly flowing hot water for stinky people and dirty dishes.
Couldn't reccomend this enough, my girlfriend is going to like it too! no more dirt in the Roof Top Tent....
THey have the smaller #13 unit too, so that may be a good place to start to see if you like it.