When you’re travelling through the colder months, a diesel heater is one of the best upgrades you can add to your campervan.
It keeps your space warm, helps prevent damp, and makes off-grid camping far more comfortable.
At Obsidian Leisure, we’ve fitted and tested a range of heaters — and while there are many great brands available, we’ve found diesel heaters to be reliable, fuel-efficient, and ideal for UK climates.
This guide walks you through the key steps to fitting one safely and effectively.
🔹 Step 1: Choose the Right Diesel Heater
Diesel heaters typically come in 2kW or 5kW sizes.
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2kW units are perfect for smaller vans like Transporters or Transits.
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5kW models suit larger vans or those using the heater to warm both the living and sleeping areas.
You’ll need a 12V diesel heater kit, which usually includes:
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Heater unit
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Wiring harness
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Fuel pump and line
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Air ducting
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Intake and exhaust pipes
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Controller panel
👉 Check out the diesel heater kits available via Obsidian Leisure — all fulfilled by Amazon for quick delivery and reliable performance.
🔹 Step 2: Plan Your Installation
Before cutting any holes, decide exactly where your heater will go.
Most installations are under the passenger seat or in a rear corner.
✅ Things to consider:
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Keep it away from fuel tanks, wiring looms, and water lines.
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The exhaust outlet must pass through the van floor and vent safely outside.
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Allow easy access for servicing and airflow.
Take your time measuring — correct positioning is the difference between an easy install and a headache later.
🔹 Step 3: Prepare the Mounting Area
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Mark and drill the mounting hole template for your heater base plate.
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Fit the intake, exhaust, and fuel line through the opening.
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Apply high-temperature sealant around the edges to prevent leaks and fumes.
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Bolt the heater securely to the floor or mounting plate.
👉 We stock essential installation accessories like stainless-steel exhaust clamps, fuel line fittings, and sealant options — all compatible with Dodo and Planar-style heater kits.
🔹 Step 4: Connect the Fuel Supply
Most diesel heaters draw fuel from:
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A dedicated small tank (often supplied in the kit), or
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A pickup from your van’s main diesel tank (via an auxiliary feed).
To install:
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Mount the fuel pump close to the tank (angled upwards slightly to prevent air locks).
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Connect the fuel line from the tank → pump → heater.
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Secure with clips and test for leaks.
⚠️ Safety note: Always use heat-resistant tubing and avoid routing lines near the exhaust.
🔹 Step 5: Electrical Wiring
Connect the heater’s 12V wiring harness directly to your leisure battery or a fused distribution block.
Avoid running through the vehicle’s main ignition wiring — it can overload circuits.
Connections include:
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Positive and negative power
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Controller or thermostat
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Optional remote switch or timer
Tidy the wiring with conduit or sleeving for a professional finish.
🔹 Step 6: Exhaust & Intake
Attach the stainless-steel exhaust pipe and air intake hose to the heater’s underside.
Route them safely beneath the van with clamps and brackets.
✅ Tips:
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Point the exhaust outlet backwards (never toward the van body or wheel arch).
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Keep hoses short and straight to reduce back pressure.
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Use exhaust wrap or shielding if close to wiring or flooring.
🔹 Step 7: Test & Secure Everything
Before refitting any panels:
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Double-check fuel lines and connections.
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Turn on the heater and let it prime (it may take 1–2 attempts to start).
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Check for fuel leaks, airflow, and exhaust fumes.
Once running smoothly, secure all ducts and tidy cables.
🔥 You’re done! Your camper is now ready for warm nights — even in winter adventures.
💡 Final Thoughts
Fitting a diesel heater takes patience and attention to detail, but it’s absolutely worth it.
You’ll enjoy year-round comfort, better condensation control, and improved off-grid flexibility.
While other heating options exist, diesel heaters offer an unbeatable mix of efficiency, reliability, and affordability — which is why we recommend them across our camper conversion range.
✅ Shop essential diesel heater kits and accessories at:
👉 obsidianleisure.co.uk