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  • Writer's pictureMax & Sophie In A Van

DIY Diesel Heater Box - Underslung to SAVE SPACE and homemade to SAVE MONEY! - With measurements!

Updated: Jan 13, 2023

When designing our van build we always knew we wanted a diesel heater but didn't have the money for an Eberspächer or Webasto, which led us to buying a Chinese Diesel Heater! We didn't want to lose precious space within the van for the heater so we designed and built a box to protect the unit and to mount it in underneath our van alongside our Bobil Heater. This blog is about how we did it, with some useful diagrams to help you build one too!

DIY Diesel Heater Box - Max & Sophie In A Van

We decided to build our own diesel heater box rather than buy an off the shelf version (around the £100 mark plus delivery) for a couple of reasons. We were trying to fit our diesel heater in a very specific area under our chassis and wanted to house our Bobil Heater within the box also. Having some spare chequer plate from when we stripped out our van (see that here!) also made a DIY option more cost effective for us!

Our DIY Diesel Heater Box comprises of the following materials:

And we used these tools to build it:

We started with the design of the box itself, using the above materials, which for us had to hold a 2kw Diesel Heater and a Bobil Heater.

Diesel Heater Box Drawings

For a 2kw Diesel Heater Box you will need to use these dimensions:

Diesel Heater Box Drawings

For a 5kw Diesel Heater Box you will need to use these dimensions:

Diesel Heater Box Drawings

Once we had finalised our design we started by measuring, marking out and cutting our chequer plate to the drawing's dimensions. We lubricated the marked line and jigsaw blade with cutting oil prior to cutting, to limit the amount of swarf, and allowing a smoother cut.

DIY Diesel Heater Box - Chequer Plate, Tape Measure, Square

Now that we had all of the sections cut and laid out we could use the 90-degree clamps to hold some of the sections in place to get the feel of how the box will look.

DIY Diesel Heater Box - Chequer Plate, 90-degree Clamps

Next we took the aluminium angle and cut out a 90 degree 'V' at the points which would become corners. We then bent the aluminium angle around the first piece of the box and clamped it into place. Once we were happy with how it would all fit together we drilled pilot holes through the aluminium angle and chequer plate every 100mm, which we then riveted through.

DIY Diesel Heater Box - Chequer Plate, Aluminium Angle

Then we drilled the next pieces of the chequer plate to the aluminium angle and riveted these all together too.

The next step was to cut and bend more aluminium angle to attach the 'flapping' ends together, again drilling and riveting them to secure. Then we cut short lengths of aluminium angle and attached them onto the corners.

Now that the box was all secured together we drilled 8x 8mm holes in the overlapping aluminium angle on the open side of the box. We then used a rivnut tool to attach rivnuts within the holes to allow us to bolt on the remaining side but keep easy access to the interior for maintenance once it is installed.

Riv Nut Tool

The final step was to cut holes into the box for the combustion air in and out, the fuel line, electrical connections, heated air in and out, Bobil water lines in and out and bolt holes to secure it onto the van. You may not need all of these depending on your design. Once we had cut all of the holes with a hole saw in our drill we sealed the joins in the box with silicone.

Diesel Heater in Box

Finally we could fit our diesel heater and Bobil heater into the box, and fix it in place under the van.

Check out Episode 20 of our YouTube Van Build to see how we built a DIY Diesel Heater Box in more detail!

Max & Sophie In A Van YouTube

If you enjoyed this blog please give it a like and a comment or check out our daily updates on our Instagram and YouTube!

Some of the links in this blog are affiliate links so we do get some pennies (at no extra cost to you!) if you follow the link and make a purchase.

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