A primary driver for purchasing the Decatur and renovating it was the ability to have a toilet and shower inside the trailer. Our Boles Aero has a slide-out porta-potti for emergencies but no provision for a shower. We have a portable on-demand shower water heater and a shower tent, but that arrangement is not optimal. For one it means you'll be draining the shower "grey water" and most campground technically don't allow it (although I see this arrangement used frequently in National Forest campground).
If you're going to have a shower then you really need a water heater. Cold water shower might be an occasional delight but not something I want to endure every time I feel the need to shower. So in this post I'll focus on the water-heater trade-off's I've considered. I'll address the toilet trade-offs in another post.
The first trade is a water heater with a tank vs a tankless, or "on-demand" water heater. I believe we'll be using the Clipper more in locations such as National Parks where hook-ups are unavailable or limited. So fresh water will be limited to what we're carrying and we'll also need to capture our grey water. After reading a lot of forum posts from people who've used both I've decided that a water heater with a tank will probably be best for Decatur. We'll need to watch our water usage carefully so the waste associated with an on-demand system isn't practical, plus limited hot water will encourage shorter showers conserving water as a result.
Given we'll likely be off-grid much of the time it's obvious that we'll need to rely on propane as the primary fuel source. The real question is whether we also want electric heating to supplement propane when we do have it available. As you'll see all the of the options include the ability to have supplemental electrical heating as an option, so that decision can be deferred.
Tank materials vary between water heaters. Some use a porcelain-lined tank and others use an aluminum tank. The porcelain-lined tanks require an anode that needs to be replaced periodically and they also weigh more.
Water heaters are primarily delineated based on tank capacity running from about 3 gallons up to 16 gallons. Based on forum posts and some online articles it seems that an efficient shower requires on the order of 5 gallons of water. If you take drastic measures you can use a lot less, but I'll assume 5 gallons. If about 1/2 of that water is hot and we need to provide 2 showers in sequence then a tank capacity in the 5 gallon range is necessary.
In the past there were water heaters that relied on a pilot light. You'd need to go outside the trailer and light it when you got to camp. Now they all appear to have electronic ignition (aka "direct spark ignition"): there is a switch mounted inside the trailer and it (along with the water heater thermostat) initiates the ignition of the burner.
A few of the models from Dometic include a thermostatic mixing value that combines cold and hot water based on a user-selected temperature setting. If you crank up the temp on the water heater then this can effectively provide more hot water, albeit at a slightly lower temp. The literature also says there is the added benefit that hotter tank water kills pathogens better. In reality though you can get the same advantages by installing a shower faucet with an integrated thermostatic mixing valve. There are a large number of inexpensive shower faucets with mixing valves so this is a much more economical approach.
How fast the water heater can "recover" from being emptied is known as the "recovery rate". This depends on the tank type, water heater burner size and also the design of the heater. Faster is generally considered better but it may not be a real issue if you don't have a lot of people lined up to take showers.
The physical dimensions of the water heaters varies a bit however within each size/capacity category they are very close in dimensions.
Here are the water heaters I'm considering:
Dometic WH-6GA/WH-6GEA (gas only/gas-electric)
- 6 gallon capacity
- electric option WH-6GEA
- Aluminum tank (no anode)
- 17 lbs empty weight
- TBD/TBD recovery rate (gallons/hour - gas/electric)
- 12.88" H x 12.88" W x 19.5" D
- Thermostatic mixing valve available ("EXT" model and also upgrade kit)
Suburban SW4D/SW4DE
- 4 gallon capacity
- electric option SW6DE
- Porcelain-lined steel tank (anode required)
- 29 lbs empty weight
- 7.6/6.1 recovery rate (gallons/hour - gas/electric)
- 12.75" H x 12.75" W x 16.125" D
Suburban SW6D/SW6DE
- 6 gallon capacity
- electric option SW6DE
- Porcelain-lined steel tank (anode required)
- 32.9 lbs empty weight
- 10.1/6.1 recovery rate (gallons/hour - gas/electric)
- 12.75" H x 12.75" W x 19.19" D
There are a couple other interesting options that I've read about: the Propex Malaga 5/5E; and the Truma Combi.
The Propex Malaga is used primarily in European caravans. Propex manufactures very popular small propane furnaces that are widely installed in camper van conversions. I have one of the HS2000 furnaces installed in my Boles Aero. The Malaga is a small capacity water heater (13 liters/3.4 gallons) that is correspondingly small in size. An attractive feature is that it doesn't require the large sidewall cutout that the Dometic and Suburban models require. Rather it's installed from inside the RV with a relatively small exhaust vent through the sidewall. However it doesn't seem to have any sales or support base in the US but it appears it can be ordered.
The Truma Combi is a combination furnace/water heater. They are quite popular in European caravans and are also being installed by US RV manufacturers as well. The water heater capacity is small (10 liters, 2.6 gallons) and the physical dimensions are larger than other water heaters but that's to be expected since a furnace is integrated. I imagine it also is more efficient.
The major downsize of the Truma Combi is that in the US it is not available for DIYers. It's also quite expensive, much more than a furnace and water heater purchased separately. There is a work-around for these downsides: there are Chinese knock-offs available from several sources including AliExpress. I priced several in the $1300 range which is similar to the cost of a separate water heater-furnace pair. The problem would be lack of support.
As of the writing of this post I'm leaning towards the Dometic WH-6GEA. It's a bit lighter but more importantly it requires less maintenance (no anode replacement) than the Suburban units and the prices I've found are comparable.
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