Every van build in the UK faces the same question: how do you stay warm when it is 2°C, damp, and the wind is cutting through the Lake District like a knife? Diesel heaters are the default answer for good reason — they run off your van's existing fuel tank, draw minimal battery power once running, and produce dry, consistent heat that cuts through UK humidity in a way gas never will.
But the market splits cleanly down the middle: Chinese diesel heaters (CDH) at £100–200 versus German/European units from Webasto and Eberspacher at £800–1,200. That gap has grown over the last five years as CDH quality has improved, and the right choice depends on how you use your van.
Chinese Diesel Heaters vs Webasto/Eberspacher — The Real Difference
The price difference is not arbitrary. Webasto and Eberspacher have been making vehicle heaters since the 1930s and 1940s respectively. Their units go through type approval, CE certification, and real endurance testing. A Webasto Air Top 2000 STC has a documented MTBF (mean time between failures) of over 5,000 hours. A Chinese Afterburner or Vevor unit costs a fifth of that, and the components inside reflect it.
But the gap has narrowed. The early CDH units (2015–2018) were notorious for controller failures, fuel pump ticking that woke entire campsites, and PCBs that burned out after one winter. The current generation — units from brands like Autoterm, Planar, and even the generic "2kW parking heater" sold on Amazon — use far better controllers, quieter fuel pumps, and properly rated glow plugs. Some of the newer controllers even support altitude compensation (up to ~3,000m), which is essential if you spend time in the Scottish Highlands.
What you actually pay for with Webasto/Eberspacher:
- Spare parts availability — if your Webasto Air Top 2000 glow plug fails in Inverness, you can have a replacement by 10am the next day via any commercial van parts supplier. CDH glow plugs are generic and may take a week from eBay.
- Noise engineering — the combustion chambers are better baffled. An Eberspacher D4 running at full output is noticeably quieter than a CDH unit. The difference is marginal at low output but distinct at 2kW+.
- Certification — Webasto units carry E-mark certification (vehicle type approval). If your van goes through an MOT with a permanently installed heater, some testers will check for basic safety. A Webasto passes. A CDH may raise questions depending on the tester.
- Fuel pump — Webasto uses a metering pump with a rubber damping mount. The standard CDH fuel pump clicks audibly. A £5 rubber mounting bracket sorts most of this, but out of the box the German pumps are quieter.
What CDH units do better:
- Price — a full 5kW CDH kit with digital controller, fuel tank, exhaust, and all ducting costs £130 delivered. That is less than a Webasto glow plug replacement kit.
- Self-repairability — when a CDH unit breaks, you can open it, identify the failed component, and solder a replacement. Webasto units are potted and sealed. You send them to a service centre.
- Upgradability — the CDH ecosystem has developed around the generic controller platform. You can buy Bluetooth controllers, LCD remote panels, and even WiFi-connected thermostats for £25–50. Equivalent Webasto accessories cost £150+.
Real Price Comparison
| Unit | Cost | Typical lifespan | Spares availability | Noise at 1m |
|---|---|---|---|---|
| Vevor/Afterburner 5kW | £110–160 | 2–4 years | eBay/Amazon, 3–7 day delivery | 48–52 dB |
| Autoterm Air 2D 2kW | £280–350 | 5–7 years | UK distributors, next day | 42–46 dB |
| Planar 2D 2kW | £320–400 | 5–7 years | Specialist stockists | 40–45 dB |
| Eberspacher D4 Airtronic | £850–1,100 | 10–15 years | Any van parts shop | 38–42 dB |
| Webasto Air Top 2000 STC | £800–1,200 | 10–15 years | Any van parts shop | 36–40 dB |
| Webasto Air Top EVO 40 | £1,100–1,400 | 10–15 years | Any van parts shop | 35–39 dB |
Prices include the full kit (heater, controller, fuel pump, exhaust, ducting). Installation is extra.
Installation Considerations for UK Vans
The UK van fleet is dominated by front-wheel-drive panel vans: Ford Transit Custom, VW Transporter T6, Mercedes Sprinter, Fiat Ducato, Citroen Relay. The installation principles are similar across them, but there are UK-specific gotchas.
Exhaust routing. The exhaust from a diesel heater gets hot — 200–300°C at the outlet. It must terminate outside the van footprint, pointing away from the underside. Most installs route the exhaust through the floor near the passenger-side chassis rail, with a 15–20mm hole through the floor pan. A heat shield (included with most kits) between the exhaust pipe and the floor is mandatory. UK vans are often undersealed; drilling through underseal creates a rust trap. Wire-wheel the area clean before drilling, then apply waxoyl or underseal around the grommet after installation.
Fuel tap. The best installation taps into the van's existing diesel fuel line (either a T-piece in the return line or a dedicated pickup in the fuel tank sender unit). Running a separate fuel tank inside the living space is a bodge that creates diesel smell, reduces cargo space, and can fail MOT (fuel tanks inside the passenger compartment need specific crash protection). For a Transit Custom, the fuel tank sender is under the driver's seat — accessible through an access hatch. For a Sprinter, the pickup is under the passenger side floor panel.
Altitude compensation. If you plan to take your van to Scotland — Cairngorms, Glen Coe, the Highlands — altitude compensation matters. At 600m+ (common on the A9 and in the Highlands), a standard CDH without altitude adjustment will produce a sooty flame, increased CO, and eventual failure. The newer Autoterm and Planar units have this built in. Some generic CDH controllers now offer an altitude adjustment setting in the advanced menu. For Webasto/Eberspacher, it is either standard (Eberspacher Airtronic series) or requires a high-altitude kit (Webasto).
Mounting position. The heater unit itself can be mounted under the van (common with Webasto/Eberspacher) or inside a seat base. Undermount installation is cleaner but exposes the unit to road spray, grit, and speed bumps. Most UK self-builds mount the heater inside a passenger-side seat base, with the combustion intake and exhaust ducted through the floor. This keeps the unit dry and accessible for servicing.
Power Consumption — Startup vs Running
This is where many van lifers misjudge their system. The startup draw is significantly higher than running.
| Heater | Glow plug draw (cold start) | Fan draw (startup) | Running draw (low) | Running draw (high) |
|---|---|---|---|---|
| 2kW CDH | 8–10A for 60–90 sec | 1.5A | 0.5–1A | 2–3A |
| 5kW CDH | 10–12A for 90–120 sec | 2A | 0.8–1.5A | 3–5A |
| Webasto Air Top 2000 | 12–14A for 60 sec | 2.5A | 0.6–1.2A | 3–4A |
| Eberspacher D4 | 10–12A for 45 sec | 2A | 0.5–1A | 3–4A |
The glow plug startup draw is the real killer for battery systems. A 100Ah LiFePO4 battery can handle a 12A startup draw easily. But if you are running a single 70Ah lead-acid leisure battery and the heater starts in cold weather, the glow plug cycle combined with 10°C battery temperature can drop your voltage below the heater's cutoff (typically 10.5–11V). Many CDH units have a configurable low-voltage cutoff; set it to 11.5V to protect your battery.
Once the heater is running and the glow plug cycles off, the draw drops to under 2A for most units running at 40–60% duty cycle — which is what you want for maintaining 18–20°C overnight in a well-insulated van. Over a 10-hour winter night, expect 15–25Ah total draw, including the startup cycle at midnight and the restart at 6am if you have it on a thermostat schedule.
Noise Levels and Mounting
The noise from a diesel heater comes from three sources: the combustion fan (inside the heater unit), the intake air rushing in, and the fuel pump clicking.
The combustion fan noise is a low hum that transmits through the heater body into whatever it is mounted on. If you hard-bolt the heater to a metal seat base, the entire seat base becomes a sounding board. The fix is rubber isolation mounts — 10mm M6 rubber vibration dampers, available for £5 from any hardware shop. Every CDH installation should use these. Most Webasto/Eberspacher units come with them.
The fuel pump noise is the most annoying. A standard CDH pump ticks at about 3–4 Hz. In a quiet campsite at midnight, someone 20m away can hear it. Solutions:
- Mount the fuel pump outside the van on the chassis rail, using the rubber bracket that comes with most kits.
- Or wrap the pump in sound-deadening foam (NOT closed-cell — fuel pumps generate heat).
- Upgrade to a "silent" fuel pump. These use a soft plunger design and cost about £15 on AliExpress.
- Webasto/Eberspacher pumps are inherently quieter due to better damping.
For intake noise — the air rushing into the combustion chamber — fit a short section of silicone hose on the intake as a crude silencer. Several aftermarket "intake silencers" exist for £10–20.
The quietest installation layout: heater inside a seat base (not under the van), on rubber isolators, fuel pump on the chassis rail with rubber damping, exhaust ducted through the floor with a 360° exhaust tip that directs gas away, and intake routed through a 200mm hose acting as a silencer.
Sizing Guide — 2kW vs 3kW vs 5kW
This gets more wrong than almost anything else. The UK van building community has a persistent myth that bigger is better. It is not. An oversized diesel heater will short-cycle (run for 2 minutes, hit the thermostat, shut off for 5 minutes, restart), which wastes fuel, wears the glow plug, and creates temperature swings.
| Van type | Internal volume (m³) | Recommended heater size | Notes |
|---|---|---|---|
| VW Caddy / Berlingo | 6–8 m³ | 2kW | A 5kW in a Caddy will be unbearable |
| VW Transporter T5/T6 | 8–11 m³ | 2kW–3kW | 2kW is sufficient for well-insulated builds |
| Ford Transit Custom | 10–14 m³ | 2kW–3kW | 3kW for less-insulated or open-plan builds |
| Mercedes Sprinter (LWB) | 14–18 m³ | 3kW–5kW | 3kW if well-insulated, 5kW if not |
| Fiat Ducato / Citroen Relay (LWB) | 14–20 m³ | 5kW | Large open spaces need 5kW |
| Horsebox / larger conversions | 20+ m³ | 5kW–8kW | Multiple outlets needed |
The key metric: you want the heater running at 40–70% duty cycle for heat maintenance. If it runs at 20% duty cycle, it is too big. If it runs continuously and still does not reach temperature, it is too small.
UK-specific reality: a well-insulated Transit Custom with spray foam in the cavities, Armaflex on the walls, and a thick wool lining does fine with a 2kW heater down to -3°C. The same van with minimal insulation needs 3kW. A big Luton box or horsebox conversion with thin walls needs 5kW or more.
UK-Specific: Servicing, Parts, and MOT
Servicing. Diesel heaters need annual maintenance: remove the combustion chamber, clean carbon deposits from the glow plug and flame sensor, check the fuel filter (if fitted), and verify the fan is spinning freely. A Webasto dealer will charge £120–180 for this. On a CDH unit, do it yourself in 30 minutes with a Torx T20 and a wire brush.
Parts availability in the UK.
- Webasto parts: Available at Truckline, PartsWorld, and any commercial vehicle factors. Glow plugs (
£45), combustion chambers (£60), fuel pumps (~£80). Next-day delivery nationwide. - Eberspacher parts: Same coverage. Slightly more expensive than Webasto.
- CDH parts: Available on Amazon and eBay, but not at physical shops. A glow plug kit for a generic 5kW costs £8–15. A full controller board is £18–30. A fuel pump is £10–15.
MOT implications. A permanently installed diesel heater is subject to MOT inspection. The tester should check:
- The heater is securely mounted
- There is no fuel leak
- The exhaust does not enter the vehicle cabin
- Any electrical connections are sound
A well-installed CDH will pass. A poorly installed one will fail — same as for Webasto. The heater does not need to be CE-marked for an MOT, but the installation must be safe. Many testers are unfamiliar with diesel heaters and will not even check it unless there is a visible problem. The common MOT failure related to heaters is exhaust fumes entering the cabin — if the exhaust terminates under the van and the van is parked facing into wind, fumes can recirculate through the heater's own intake. Route the exhaust to the side of the vehicle, not straight down.
Best Accessories
Silencers. A 50mm ID stainless steel silencer that fits in the exhaust line reduces exhaust noise noticeably. Available for CDH units for £10–20. Webasto/Eberspacher silencers cost £50–70.
Controller upgrades.
- LCD digital controller with temperature display: included with most CDH kits (basic £5 version). Upgrade to a "7-day programmable" controller (£25) for timed heating schedules.
- Bluetooth controller: connects to your phone, allows temperature adjustment, timer, and diagnostic readout. For CDH, £30–45. For Webasto, the "EasySelect" Bluetooth module is £120.
- WiFi controller: integrates with smart home systems. Rarely used in vans but available.
Fuel pump upgrade. The standard CDH pump (the "ticker") can be replaced with a silent pump. Vevor and Afterburner now sell "silent fuel pumps" as separate items for £12–18. The upgrade is plug-and-play on most generic CDH units.
Diagnostic cable. For Webasto units, the USB diagnostic cable (£50) lets you read fault codes from a laptop. Equivalent CDH diagnostic tools cost £15 on Amazon.
Combustion chamber cleaner. A £10 wire brush kit designed for diesel heater chambers keeps carbon deposits under control.
The Verdict
For a weekend campervan or seasonal van lifer: a 2kW or 3kW CDH unit from a known supplier (Autoterm, Planar, or even a well-reviewed brand on Amazon) is the sensible choice. Install it properly with rubber isolators, mount the fuel pump externally, and service it annually. Budget £160 for the kit, £30 for installation consumables (grommets, rubber mounts, wiring), and £15 for a silent fuel pump. Total under £200.
For a full-time live-in van, a high-mileage camper, or anyone who wants the peace of mind of dealer-serviced equipment: buy an Eberspacher D4 or Webasto Air Top 2000 STC. The premium gets you certified safety, immediate parts availability at any UK van factor, and resale value (a Webasto-equipped van sells faster and for more than one with a generic CDH).
Do not buy the cheapest 5kW CDH on Amazon for £80. The failure rate on the truly bottom-tier units (no-name brands with 1,000+ glowing reviews that look auto-translated) is high, the fuel pumps are loud, and the controllers fail. Spend £130–160 on a mid-tier CDH from a brand with UK-based customer support. The difference between an £80 heater and a £140 heater is the difference between having heat all winter and spending January waiting for a £4 part from Shenzhen.
