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Diesel Heater for a Van: Sizing, Install and Safety
Updated October 20, 2026
A diesel air heater is the most popular way to heat a camper van in cold weather. It burns a small amount of fuel, heats air through a sealed heat exchanger, and keeps a van warm for a whole night on very little fuel. Here is how to size and install one safely.
2 kW vs 5 kW
- 2 kW heaters suit most vans, from small vans up to typical high-roof panel vans, especially if insulated.
- 5 kW units suit large vans, buses, poorly insulated spaces or very cold climates — but in a small van they often run at minimum output, which leads to carbon build-up.
Insulation matters more than heater size. A well-insulated van with a 2 kW heater is warmer and quieter than an uninsulated van with 5 kW.
Installation basics
- Location: mount the heater inside the van (under a seat or in a cabinet) or underneath in a protected box, on a flat, rigid base.
- Combustion intake and exhaust: both must run outside the living space, through the floor, with the exhaust pointing away from doors, windows and the intake. Use a proper floor gasket and sealed fittings.
- Exhaust heat: keep the exhaust pipe clear of fuel lines, wiring and brake lines, and use the supplied insulation sleeve.
- Fuel: draw from a dedicated standpipe in the vehicle tank, or use the separate tank. Mount the pump at the angle the manual specifies.
- Power: heaters draw high current at startup (glow plug) and low current once running — size the wiring and fuse to the manual.
Safety
- Install a carbon monoxide alarm in the living area — non-negotiable.
- Never run the exhaust inside the van or under a closed awning.
- Check exhaust joints and the heat exchanger seal periodically.
- Many owners choose professional installation; at minimum, follow the manufacturer's manual exactly.
Altitude and maintenance
At high altitude, combustion can run rich and soot up; some heaters have altitude settings or kits. Run the heater on high for a while regularly to burn off carbon, and use winter-grade diesel in freezing temperatures.
FAQ
What size diesel heater do I need for a van?
A 2 kW heater suits most vans, especially insulated ones; 5 kW is better for large vans, buses or very cold climates.
Is a diesel heater safe in a van?
Yes when installed correctly with the intake and exhaust outside the living space and a carbon monoxide alarm inside.
Can a diesel heater use the van's fuel tank?
Yes, typically via a dedicated standpipe fitted into the tank, or you can use the separate tank supplied with the heater.