Diesel Heaters for Campervans (UK): The Complete, No-Faff Guide

If you want reliable, dry heat without being tied to a campsite hook-up, a diesel air heater is your best friend. Below, we explain how they work, how much they cost to run, how to keep noise low, and the key safety and installation requirements we insist on for VW Transporters.

How diesel heaters work

A compact unit burns a small amount of diesel in a sealed chamber and blows warm, dry air into the living space. Combustion fumes and moisture exit outside via the exhaust. Result: warmer and drier cabin air, ideal for UK condensation control.

Why campers choose diesel

• Off-grid warmth anywhere (moors, coast, rallies).

• Fast cosy-up from cold to comfy in minutes.

• Drying power for wet jackets/boots; less morning fog.

• Sips fuel: typically 0.2–0.25 L/hour on low/medium.

Real-world running costs at a glance

Use your own prices with the quick formulas below. Figures shown are realistic UK ranges for a 2 kW diesel air heater.

Diesel heater

• Typical consumption: 0.10–0.18 L/h (low) · 0.20–0.30 L/h (medium)

• Quick formula: Cost/hour = Fuel use (L/h) × Diesel price (£/L)

• Example (medium): 0.22 L/h × £1.60 = -£0.35/h → 8 h = £2.80

• Notes: brief start-up uses a touch more; colder nights/poor insulation push usage up.

Electric on 240 V hook-up (EHU)

• If electricity is included in your pitch fee, the marginal cost is £ 0/h.

• If metered (typical £0.30–£0.40/kWh):

  
  

1 kW heater £0.30–£0.40/h (8 h = £2.40–£3.20)

2 kW heater £0.60–£0.80/h (8 h = £4.80–£6.40)

Tip: many UK sites are 10 A; a 2 kW heater (~8.7 A) leaves little headroom for kettles/hobs.

Bottom line

• With included EHU, electric heat is effectively free on the night.

• With metered EHU, diesel and electric are often similar per hour; diesel usually wins off-grid.

• Comfort = heat + a small overnight vent (prevents condensation), whichever option you use.

How quiet can it be?

Two sounds matter: a soft fan whirr and a fuel-pump “tick.” Good installs tame both.

Noise-reduction we use

• Rubber-isolated pump mounting outside the living space (correct angle/height).

• Intake silencer on combustion air; correct exhaust routing.

• Smooth ducting with gentle bends (no tight kinks).

• Controllers with eco/low or staged start to avoid big bursts at night.

Result: a low whoosh comparable to a laptop fan, sleep-friendly for most people.

Safety essentials, non-negotiable

• Professional installation: correct fuel pick-up, exhaust, heat shields and fusing.

• CO alarm: fit and test a carbon monoxide alarm (belt-and-braces best practice).

• Ventilation: never seal the van. Keep a small overnight vent (a roof fan on low or a leeward window cracked) to provide fresh air and keep windows clear.

• Clearances: keep soft furnishings away from outlets; use a guard if children or pets are aboard.

• Annual check: inspect combustion air/exhaust, ducting, filters and electrics, quick peace of mind.

The right electrical partner Euro 6/6d-friendly

Heaters require 12 V for the fan and electronics, with a higher draw at ignition. Pair with:

• A healthy leisure battery sized for hours for lights, fridge, and heater.

• A DC-DC charger (vital on Euro 6/6d) to recharge efficiently while driving.

• A mains charger for top-ups on hook-up and during storage.

• Optional lithium if you do long, off-grid winter tours (lighter, deeper usable capacity).

  
  

Best placement in a Transporter

Common T5/T6/T6.1 locations:

• Under passenger seat base (neat; short duct to rear lounge).

• Underfloor cassette (free interior space; ideal for U-shaped lounges).

• Rear quarter cabinet (works with side-kitchen layouts).

We choose based on duct length, service access, and noise isolation, not just “where it fits.”

Controls & usability

• Programmable timers for pre-heat on dark evenings.

• Thermostatic or stepped control (thermostats hold a steady temp; stepped can be quieter).

• Altitude mode for alpine trips (keeps combustion clean).

• Diagnostics for quick servicing.

  
  

Condensation: pop-tops vs high roofs

Heat + airflow is the winning combo.

• Pop-tops: add a thermal wrap and/or internal liner. Keep a mesh vent slightly open. The heater dries the air; the vent removes moisture.

• High roofs: use external cab screens (windscreen + doors) and a roof fan on low exhaust. Expect a big drop in morning fog.

  
  

Fuel & winter use, UK realities

• Most installs tap the vehicle tank, no jerrycans.

• Keep at least a quarter tank in winter; many heaters won’t operate below certain levels to protect the engine's drive range.

• Use winter-grade diesel (standard at UK pumps in winter). Run the heater monthly during the off-season to keep it in good condition.

  
  

Maintenance made easy

• Annual service: glow plug/screen, chamber clean, air/exhaust lines, filter (if fitted), electrics and error memory.

• Every trip: keep outlets clear; listen for unusual pulsing/surging.

• Storage: run 10–15 minutes monthly to keep internals clean and seals supple.

When diesel wins vs electric on EHU

• Off-grid weekends (no hook-up).

• Mixed touring (some sites, some wild).

• Wet climates (UK coast, Lakes, Scotland), you’ll value the drying effect.

• Early/late season, where sites meter electricity at higher kWh rates.

  
  

If you mostly use city campsites with included EHU, electric heat is wonderfully silent—but most UK owners still add diesel for flexibility.

Example winter setup we recommend (Transporter)

1. 2 kW diesel heater with quiet pump mounting and service access.

2. Thermal cab screens (external) + pop-top wrap (if applicable).

3. Roof fan on low exhaust overnight.

4. Leisure battery + DC-DC charger sized to your routine.

5. CO alarm and tidy, labelled fusing.

Why: rapid warm-up, low condensation, minimal noise, on grid or off.

FAQ

Will it smell like diesel inside?

No. Combustion is sealed and vents outside. If you ever notice an odour, book a check.

Can I run it all night?

Yes, on low/eco with a small vent open. Keep outlets clear and the CO alarm active.

What size - 2 kW or 4/5 kW?

For a Transporter, 2 kW is usually perfect. Bigger units tend to short-cycle and get noisy.

Is it legal to use in car parks?

There’s no blanket ban, but follow local rules and be considerate about late-night fan noise.

Need help choosing or fitting one? See our Services (heater installs, ducting, silencers, DC-DC chargers), browse winter-ready Vans for Sale or Contact us for a quote.