Campervan Heater Upgrades: Diesel Heaters Explained

A diesel air heater is the single biggest quality-of-life upgrade you can make to a campervan. On a cold January morning in the Lakes, a good heater is the difference between a cosy night and a miserable one. Diesel heaters draw fuel from the vehicle's tank and burn it to blow warm air around the van — no gas, no hookup, no noise from a 240V blower.

How they work

The heater is a small box mounted inside or underneath the van, plumbed into the fuel supply and with a duct running warm air into the living space. A controller on the wall lets you set a temperature or timer, and the heater cycles on and off to hold it.

• They use surprisingly little fuel — around 0.2–0.5 litres per hour at low output.
• They're loudest at startup when they burn off the ignition, then settle to a low hum.
• Most units are around 2kW–5kW, and for a typical panel van 2kW is plenty. Bigger is not better; a 5kW unit will just cycle more often.

Fitting and fuel

Proper fitting matters more than the brand. Most UK installs tap into the vehicle fuel line or use a separate small tank. Air intake and exhaust must exit through the floor with a gap to the ground, well clear of anything flammable.

• Route the exhaust to the outside so fumes can't find their way in.
• Mount the pump away from living areas — the ticking is a common complaint.
• Position the controller where you can reach it from bed.

If a heater smells of diesel or soots up the windows, stop using it and get it checked. Used correctly, diesel heaters are very safe.

What it costs

A known-brand heater from Webasto or Eberspächer typically costs £800–£1,300 fitted, with the units themselves around £500–£900. Budget Chinese clones start at £100–£200 but the controllers, pumps and reliability are hit and miss. Fitting it yourself can save a lot, but if you're not confident with fuel lines, pay a professional.

A heater adds real value to a van and is a genuine selling point. When you're ready to move on, a well-equipped van sells faster — see our guide to selling your campervan. And before you fit anything, it's worth checking campervans for sale to see what already has heating built in.