Our step-by-step guide from start to end of how we installed the heating and hot water in our van, including all of the trials and errors in between. We’ve included the cost of all materials used to give an idea of what to expect when considering converting your own van.

Making a plan

Choosing a diesel heater

Making the heater coil

Creating the hot air

Total cost and materials


Making a plan:

The further North we go, the colder the countries are going to get. We knew we would need some kind of heater for the living area that would use minimal energy and not involve running the van engine. Additionally we wanted the luxury of hot water for showers, washing clothes and washing up, so we could live self-sufficiently and not need to stay on campsites. We decided we would heat the van using a diesel heater like the ones used on boats. We bought an Eberspacher Hydronic D5WZ diesel heater, usually used for pre-warming engines in vans, and created the entire plan around it. It would be fed from its own little jerry can with a small fuel line plumbed in as opposed to being fed from the van’s diesel tank.

- To convert its water-heating abilities into air-heating abilities as well we would need to adapt the heater matrix system from a car and plumb it into the heater by feeding it from the heater coil we would make. This would then blow warm out out through a vent built into part of the bed frame.

- The heating and hot water would be controlled by an Eberspacher Easy Start controller which had to be the same brand as the diesel heater or it wouldn’t have been compatible. However later in the project we had no luck getting the controller to fire up the heater, and instead swapped it for a simple light switch.

- As we could not find any pre-made hot water tanks that were the right type or size for what we wanted, we realised we would need to build our own from scratch. The hot and cold water tanks would be made from stainless steel chafing dishes, usually used in the catering industry for buffets, and inside the hot tank would run a heating coil through which the Eberspacher would heat and circulate coolant fluid with the aid of a 12V pump. This same coil would also act as the radiator for the heater matrix, providing hot air.

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Choosing a diesel heater:

After looking at the pros and cons of different brands of diesel heater such as Webasto we eventually decided to go for an Eberspacher Hydronic D5WZ which we bought secondhand for £70, the reason being it would work out cheaper for us to buy a Hydronic model which only heats water and is often used in truck engines, than it would be to buy an Airtronic which cost significantly more but are often used on boats for heating and hot water.

The Eberspacher runs on diesel and uses 12V to fire up; it uses just 0.5L of diesel an hour to run and can heat water to 100ºC. The only downside is our model of Eberspacher is significantly louder than the heaters which are designed to be run at night in motorhomes and on boats, which sort of makes you feel like you’re on a rocket ship about to take off. But we don’t mind the noise, really.

When it arrived we gave it a full service to check it was all in working order. 

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Making the heater coil:

The heating coil was a challenge to make; while it may not be the prettiest looking thing, it would do the job nicely. We hired a pipe-bender so we could bend a 6 metre long 13mm diameter stainless steel tube into something resembling a coil that would fit inside the hot tank. It required every ounce of elbow grease we had and then some - it took three of us to bend the tube by hand. Then we drilled two small holes in one end of the hot tank to accommodate the heating coil, which we fed the two ends through and tig-welded in place. Finally we were able to seal the hot tank and plumb the coil into the Eberspacher. 

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Creating hot air:

On one of our regular visits to the scrapyard we spotted an old Ford Focus with the dashboard conveniently removed, and disconnected the heater matrix from it, which is basically a big fan with a small radiator inside it. We removed the radiator from the heater matrix and ran the heating coil from our Eberspacher through it instead; we attached the heater matrix underneath the bed with the blower behind an air vent. We stuck some of the same weatherproofing strip we used on the van doors around it to create an airtight seal and stop the hot air just blowing back under the bed. That was really all there was to it- the blower would run off 12V and could be turned on via its own power switch located under the bed next to it. In hindsight it would’ve made our lives easier to have the power switches for the blower and the heater on the wall in the living area rather than having to lift the mattress to find it, but at least it’s all neat and out of the way.

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Once we had all of the pieces for the heating, plumbing and electrical systems, we could install them all together.

We screwed the water pumps to a sheet of ply at the back of the service area, connected them to the hot and cold tanks using Speedfit and to the diesel heater and the two system expansion tanks (also taken from scrap cars) using thick-walled car heater hose and jubilee clips. The heater was bolted down to its own little shelf next to the 5 litre jerry can and strapped in using a ratchet strap for easy removal for refilling. Then we screwed the heater matrix to the bed behind its air vent.

Something that always crops up when we’re showing people our van is: “What is that on the side of your van?!” Well, the exhaust for the Eberspacher needed to go somewhere and it wasn’t long enough to reach from its place down through the floor like typical heaters, so instead we mounted it to the side of the van. It acts like a small outdoor heater if you stand next to it, and makes a noise like a rocket ship.

In total it takes the system about 20 minutes to fully heat up our hot water tank to around the temperature of a kettle - around 10 minutes to be hot enough to give us warm air - and we can enjoy the luxury of a 60 second outdoor shower each. Once we were on the road, when the nights got cold enough to need the heating on, we found we would only need to refill our 5L jerry can about every week and a half to two weeks.

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Total cost and materials used:

Eberspacher Hydronic D5WZ, secondhand - £70

4 20L chafing dishes from eBay - £40

5L jerry can from a local hardware shop- £8

Heater matrix & expansion tanks from scrapyard - £5

6m 13mm diameter stainless steel tube from a local steel merchant - £24

Hiring a pipe bender for one day - £20

Pipes and fittings - £17.50


Total cost: £184.50

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