We knew we wanted to boondock for up to seven days at a time without resupplying. I’m hoping that a 35 gallon fresh water tank will meet that need. That’s with very limited “navy” type showers. This water tank will be installed on the right side of the van by the right rear wheel well. This will help balance out the weight of the kitchen area on the left.
We plan on carrying a 5 gallon collapsible jug for extra water if needed and to do refills from streams if available. We do have a variety of water filtration and purification techniques that we can use for wild water treatment.
We will have only one water fixture on board – the kitchen sink. The kitchen sink uses a faucet head mounted on a hose so that it can be used for showering inside or outside as well.
Underneath the kitchen sink, mounted underneath the driver-side of the vehicle, is a 15 gallon gray water tank.
A standard 2 gallon per minute marine pump is used to deliver water from the water tank to the faucet.
The water heater was the hardest plumbing problem to solve. The best solution is a Rixen gas or diesel fueled combination cabin heater and water heater, but it costs about $6500. We weren’t willing to go there.
Here are the options we considered:
Whale Expanse. The nice thing about this unit is the vents can be done through the floor. Up to this point we've avoided cutting any holes in the side of the van for a lower key approach. But this does have a small tank which must be kept warm, thereby requiring the unit be left on and consuming energy.
Espar Rixen combination cabin and water heater. This is packaged modification of the Espar diesel/gas fired cabin heaters. $6500!
Standard RV tank based water heater. Again, these units have tanks which must be kept warm.
Propane fired tankless water heaters. These seemed ideal – no energy consumption except when in use, unlimited hot water, low fuel consumption, but until we found the Excel unit, they all require that you mount them outside or with a vent, and their low-flow performance is terrible.
We ended up selecting the Excel ventless on-demand propane fired water heater. Propane fired water heaters are extremely efficient, and the unit we have selected provides enough hot water for about three months of showering before we need to refill the propane tank. Normally running a ventless propane water heater inside of a small enclosed space without ventilation can present health and condensation problems, but because we simply don’t have enough water to run it very long, and we plan on using it only briefly anyway, we don’t see any significant risk from this approach. We do plan to run the vent fan whenever it’s in use just to keep the moisture level down.
I did purchase this unit and test prior to finalizing my decision. It's able to run effectively at extremely low water volumes of 0.5 gallons per minute, which I've never heard of in any other unit. Most of these units struggle with cycling, providing alternating scolding and freezing water at lower flow volumes. This unit delivered a nice, even and consistent temperature making it suitable for both Navy type showers and light dishwashing.
It will be installed in the garage area with convection airflow coming through the floor vent and up the driver-side bed window area.