Deciding on whether to have a hot water system in your van can be a tough decision. It can add significant cost and complexity.
I settled on a bit more of a DIY version that costs less and for the past 4 years has worked great. Let’s have a look at the most popular hot water systems and why mine is a great option if you don’t have deep pockets.
Does your camper van need hot water?
I know you want it but do you really need it. Obviously a very personal choice here.
We opted to go with hot water because we like to winter camp and chase powder. Having a little warm water for the dishes is REAL nice.
If we lived down South and weren’t interested in chasing snow, hot water might have not been such a priority. But for us we absolutely love it!
Campervan Hot Water Heater Options
Let’s have a quick look and get familiar with the different ways you can live the good life with hot water in your van.
Coolant Heat Exchange Systems
In my opinion, this is the top dog in a campervan hot water heater. These work by having a water tank that is heated by coolant that circulates through it.
While driving the coolant from the engine heats it or you can heat it via a diesel/petrol fired coolant heater.
This system even allows you to preheat your engine block which is a great feature for the cold.
IsoTherm is just one option but a very reputable one that has a long following in the sailing and yachting circle. Just the tank will run you about $750.
To heat via coolant lines you’ll need to tie into the engines coolant system which is no small task. For us the cost was too great and a bit complex for the DIY’er.
Diesel or petrol fired hot water systems
The Webasto Dual Top is another great option and avoids the complexity of tying into your engine’s coolant system. The Dual Top also provides forced air heating in addition to hot water.
These are diesel/petrol fired and has an internal 11 liter hot water tank. These can even be mounted outside of the living area underneath your van. They have built in freezing protection features as well. Not cheap though at about $3,500.
Propane On Demand Hot water Systems
These are becoming a popular option for those that are using propane. These on-demand hot water systems can be hooked up to a propane tank and work great for outdoor showers.
You’ll see people with these hanging on their back doors. They are not designed to be used inside because they require ventilation. They are however very affordable at around $200.
Here you have the traditional RV propane hot water heater. These require a large hole cut in the side of your van and in my opinion are a pretty dated way of going about hot water. There are far better options in my opinion.
Our affordable 12 volt van hot water system
We opted for a 12 volt system that heats while driving or on shore power. This avoided the complexity and cost of a coolant heated version.
You can run it off batteries sparingly but it does draw quite a bit of power. The version we built uses about 35 amps while the element is going. The element of course turns off once up to temperature.
We used a residential Rheem 6-gallon water heater from Home Depot. They now have a 2.5 gallon version that might be a good option but I’m not sure how it would do for an actual shower.
These are of course designed to run off 120v which we wanted to avoid so we swapped the heating element to a 12v element.
The 12 volt heating element that we ended up going with was from Missouri Wind and Solar. Here are some options from Amazon which I have not tried. I can however recommend the above Missouri Wind option.
The Missouri Wind element comes in 3 different wattages.
- 200 watts drawing about 16 amps
- 400 watts at 35 amps
- 600 watts drawing about 50 amps
We have the 400 watt version.
Swapping the element is easy and no different than any other hot water heater. Here’s a video showing how if you’re not familiar with it.
How has our system worked?
We’ve been running this setup for over 4 years and it has worked flawlessly. Absolutely no issues.
Once the water heats up it stays relatively hot for a good 16 hours. At least warm enough to do some dishes. When we take showers we try to do that after it’s been on for a while.
We typically don’t stay parked for days at a time without driving to trailheads and such so we never have a problem warming it up. And when on shore power you of course are golden.
We use it a lot in winter and is easy to drain to prevent freezing. We just ran a drain pipe through the floor.
Important things to consider with this DIY hot water system
In our Ford Transit we have a heavy duty alternator so I’m confident we have enough spare amps to run the hot water heater as well as charge our battery bank while driving.
It’s important to know what your alternator is putting out because this could be a big drain and cause premature alternator failure.
It’s also important to never turn on the heating element without water in the tank. It will ruin the element.
We have an illuminated switch for the heater above the sink but I was afraid we might accidentally turn it on without realizing it. So I installed a second inline switch that kills power to the whole system that I turn off whenever I drain the tank.
This assures that even if someone turns the switch above the sink on there will be no power going to the hot water heater.
Final Thoughts
Like i mentioned earlier, we’ve been running this system for 4 years now without a single hiccup. It works great on shore power, battery(sparingly), and of course while driving.
Because the tank is round it does make it a little awkward and not very space efficient. I really like the IsoTemps mentioned above because they offer a square version.
But for a hot water system that works great and can be done for well under $300 I’m very happy with it.
I hope you found this article useful and please don’t hesitate to ask questions.
Don’t forget to follow our adventures on Instagram @outsidenomad and be sure to share this on your favorite social media so you can reference it again later.
Hey! Super cool setup, but I was wondering how exaxtly it’s linked so that it only works when you’re driving? I’m building a van and looking for hot water options, I already have an induction cooktop so I don’t want to ask any more from my battery. Do you have a drawing or anything that explains this better?
Thanks! I actually just have it wired through a relay and switch that I can turn on and off as needed. It doesn’t automatically turn on while driving although you could wire it that way. If you shoot me an email I’d be happy to shoot a few photos or video showing some more details. [email protected]
Really like your 12V hot water setup. You mention “The element of course turns off once up to temperature.”. Are you using the original thermostat on the hot water tank (so 12V goes to the thermostat vs. directly to the 12V element) or are you using some other thermostatic control that you can set to your preferred temp? Also are you using something like a Shurflo water pump to pressurize your hot water tank? Thanks!
The wiring is no different than if you were hooking the hot water heater up to 120. The only difference is the element has been swapped out to the 12v version. So you still connect your 12v power to the regular hot water heater wires which go first to the thermostat then to the element based on whatever water temp setting you set. And yes we are using a Shurflo water pump. We have several years with our hot water tank and have been full time in the van for a bit and it is working fantastic. We can even keep it on all day charging from our solar on a sunny day.
So if I understand correctly, the thermostat is also running off of 12v DC? It doesn’t require 120 AC?
That’s correct. The only power going to it is the 12V which is wired just like you would if you were installing it for 120v use.
August, I like the reassurance that you have installed an electric water heater with a 12 volt heating element. Regarding the thermostat on the water heater, I read that you did not replace the original one that came with the tank with one that could handle higher amperage. I may use a 600 watt element, and I would not use the original thermostat because that would be 50 amps, and I understand that the thermostats that come with water heaters are made for less amperage. If I used a 300 watt element, I would feel safer with using the original thermostat because it would be lower amperage. It would be 25 amps.
Also, how was the water heater wired with a switch on the wall in the kitchen? I’m assuming that the kitchen switch was connected to a relay, and wasn’t the thick copper wire that goes between the battery and the water heater element?
Jay, That sounds like a good plan with the thermostat. Like you mentioned I only pull about 25 amps so I am not worried about taxing the thermostat. But anything more would be concerning. The wall switch runs a 100 amp relay that is located right at the water heater.
What’s your reasoning for a 600 watt element? I find ours heats pretty quick.
Awesome little write up. Were in New Zealand, so we have 240v AC for on grid.. Am I correct in assuming the voltage going into the thermostat doesn’t matter, as its just a open / closed switch depending on temperature? We’d just need to get the 12v element and hook the 240v thermostat on the rheem cylinder up to the 12v battery and were good to go? We would obviously have a main / cut off switch for when not in use.
Yes that sounds right. The thermostat must just be a mechanical on/off based on the set temperature. For the main cut off switch I used a resettable breaker like this one. https://amsolar.com/rv-inverter-accessories/brkr-dc-brkr
Thanks for this post. This is a revelation to me that you can change an appliance that easily. Did you change the wire to connect the heater to a 12V plug? What size battery are you using? I have a 100Ah Lithium battery. It has a maximum charging current of 80A, so I assume this would work for a short period. I also assume that being a 200-400W heater it would take much more time to heat up. Do you have a sense of how long?
The 12v wiring going to the hot water heater will have to be sized correctly for how long the wire run is as well as the amperage/watts you end up going with. By “12V plug” if you mean a cigarette lighter plug this draws far too much current for that. This needs to be hard wired and fused. It will draw about 30 amps when running. I have the 400watt and it gets plenty warm for a shower in about an hour. I have 400Ah of Lithium as well as solar. With just 100Ah I would just heat the water heater while driving(if you have alternator charging) since it stays hot for quite a while.