A diesel heater is one of the most worthwhile things you can add to a van. It runs on the same fuel as the engine, draws very little power from your battery, and keeps the van warm and dry through winter without burning through gas bottles or relying on shore power. Once installed and set up correctly, it runs quietly in the background and you barely think about it.
The market is dominated by affordable Chinese units that are largely clones of European designs. They work well when set up correctly. This guide covers what to buy, what 2kW versus 5kW actually means for a van, what you need beyond the kit, and the problems to be aware of before you buy.
Quick picks by setup
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2kW or 5kW — which one do you need?
This is the first question everyone asks and the answer is less obvious than it looks. Here is the important thing to know upfront: there are only two physical heater bodies made for Chinese diesel heaters. A 2kW body and a 5kW body. Every unit sold as 3kW, 4kW, 6kW or 8kW is simply a 5kW body with its fuel and air settings adjusted in software. You are not buying a fundamentally different heater, just a different tune.
| Size | Max output | Best for | Typical fuel use | Power draw |
|---|---|---|---|---|
| 2kW | 2kW (6,800 BTU/hr) | Small vans, mild climates, well insulated builds | 0.2–0.35 L/hr at max | 1–4A running, 8–12A startup |
| 5kW | 5kW (17,000 BTU/hr) | LWB high-roof vans, cold climates, larger spaces | 0.5–0.55 L/hr at max | 1–4A running, 8–12A startup |
For a standard long-wheelbase Transit, Sprinter or Promaster with decent insulation, most people are better served by a 5kW unit running at moderate output rather than a 2kW unit running flat out. Here is why:
A 2kW unit heating a large van will spend most of its time at 80–100% output to keep up with heat loss. At full output it is louder (higher fuel pump frequency and faster fan) and puts more stress on the glow plug. A 5kW unit doing the same job runs at 30–40% output, which is much quieter, more efficient per litre of fuel, and is easier on the glow plug.
The 2kW makes sense for smaller vans (Transit Connect, NV200, Caddy, short-wheelbase builds), well-insulated vans in mild climates, or anyone on a strict budget since 2kW kits are cheaper to buy.
How a diesel heater actually works
The key safety feature of a diesel air heater is that combustion happens in a completely sealed chamber. The air you breathe inside the van never touches the combustion gases or the exhaust. Two separate air circuits run side by side:
- Combustion circuit: Fresh air is drawn in from outside the van through a pipe in the floor, diesel is injected and burned, and the exhaust gases exit through a separate pipe that vents outside and away from the vehicle.
- Cabin air circuit: A separate fan pulls air from inside the van, passes it over the hot combustion chamber (without mixing it with exhaust gases), and blows it back into the cabin as warm air.
A solenoid fuel pump mounted near the fuel source delivers diesel in precise pulses, typically 1 to 5 pulses per second depending on the heat setting. You can hear this as a rhythmic clicking or ticking. It is completely normal — the click confirms fuel is being delivered. The glow plug ignites the fuel on startup and stays on to stabilise combustion in the first few minutes.
The whole system draws 12V from your battery. Startup draws 8–12A for roughly 30–60 seconds (mostly the glow plug heating up). Once running at a steady temperature, draw drops to 1–4A depending on the heat setting — a 100Ah LiFePO4 battery can run a diesel heater for an entire cold night with plenty left over for morning.
Related guide: Best LiFePO4 Battery for a Van Build — Choosing the right battery size and charging setup for your van.
Budget kits: what to buy
AU Focus 2kW MZ Gen 4 — Best for Australian builds
The AU Focus Gen 4 has become the default choice for Australian van and caravan builds. Over 90 Australian caravan manufacturers fit it as standard, which tells you something about its reliability and support in the local market. It is sourced from Chinese manufacturing but warranted and supported through Australian distributors, with a 24-month warranty and $15 flat-rate shipping nationwide.
The Gen 4 kit includes the heater unit, Bluetooth LCD controller, 5L stainless steel fuel tank with fuel level gauge, fuel pump, all hoses and wiring, and installation hardware. The Bluetooth app lets you set timers and monitor the heater from your phone. Parts are available locally if something needs replacing, which is the main practical advantage over generic brands.
Pros
- Best local warranty and support in Australia
- Used by caravan manufacturers — proven reliability
- Stainless fuel tank with gauge included
- Bluetooth app control and timer
- Parts available locally
Cons
- 2kW only — may struggle in large vans in cold climates
- More expensive than generic Chinese units
- Altitude adjustment is manual (menu setting), not automatic
HCALORY 2kW with Bluetooth — Best budget for US builds
The HCALORY 2kW is the most popular budget diesel heater on Amazon US for good reason. The 2025 updated motherboard resolved the stability issues common in older versions, the Bluetooth app is well regarded, and the altitude adjustment function (available in the app) makes it practical for anyone who drives through elevated areas. The 10L tank gives a longer runtime than smaller 5L kits.
At around USD $99–$129, it is hard to argue with the price for an entry-level van build. Glow plugs and fuel pumps are widely available on Amazon at low cost if a part ever needs replacing. It is not as refined as an Autoterm and it will not last as long, but for a first van build or occasional use it does the job reliably.
Pros
- Excellent value for money
- Bluetooth app with altitude adjustment
- Updated 2025 motherboard — more stable
- Large 10L tank included
- Replacement parts widely available
Cons
- Build quality lower than mid-tier options
- Fuel pump click audible inside the van
- Glow plug needs checking and replacing periodically
- QC varies between production batches
VEVOR 2kW Bluetooth — Solid budget alternative
VEVOR is a well-established Chinese brand with good product support and a wide parts network. The dual 12V/24V version is worth considering if you ever plan to run a 24V system, or if you want the flexibility. The Bluetooth variant includes altitude adjustment and a 10L tank. Available on both Amazon AU and Amazon US with Prime shipping.
Mid-tier: step up in quality
Autoterm Air 2D (Planar) — Best for full-time or cold climate use
The Autoterm Air 2D (also sold under the Planar brand) is made in Latvia and sits in the gap between budget Chinese units and premium Webasto or Espar heaters. It uses a brushless induction motor rather than the brushed motors in Chinese units, which makes it significantly quieter and gives it a longer service life. Altitude compensation is automatic — the unit adjusts itself without you needing to go into a menu.
It is rated for -45°C ambient temperature, which covers anywhere in Australia or most of the US. The 24-month warranty is backed by Autoterm's international distribution network. At roughly USD $500–$650 or AUD $800–$1,100, it is a big step up in price, but for full-time van life it is a much more comfortable long-term option than a budget unit that needs annual glow plug swaps and occasional troubleshooting.
Pros
- Much quieter than Chinese units
- Automatic altitude compensation — no menu adjustment
- Longer service life (brushless motor)
- Properly certified (122R and 10R)
- Good international parts and warranty support
- Rated to -45°C
Cons
- Significantly higher price than budget Chinese units
- 2kW only — same sizing limitations as other 2kW units
- Less widely stocked locally in Australia
What you need beyond the kit
A carbon monoxide detector is not optional. Diesel heaters use a sealed combustion chamber but any damaged exhaust joint, cracked pipe, or poorly sealed floor penetration can let exhaust leak into the cabin. CO is odourless and will kill you while you sleep. Fit a 12V CO detector before you use the heater for the first time.
What most kits do not include
- Carbon monoxide detector — the most critical additional purchase, full stop
- Quality stainless hose clamps — the supplied clamps are often undersized; replace them
- Exhaust sealant or exhaust putty — seal every exhaust joint where the pipes connect
- Flexible hot air duct hose and grille — if you want to direct warm air to a specific spot rather than just blowing it from the heater outlet
- Remote battery (A27 size) — the wireless remote uses one and it is never included
- Self-amalgamating tape or heat wrap — to protect the fuel line where it passes through metal or near hot surfaces
- Extra fuel line — if you plan to tap the van's main diesel tank rather than use the supplied separate tank, you will need a longer run
- Grommets — for protecting cables and hoses where they pass through drilled holes in the floor
Common problems and how to deal with them
The fuel pump click
You will hear a rhythmic clicking or ticking from the fuel pump during operation. This is the solenoid firing precise pulses of diesel to the combustion chamber — typically 1 to 5 times per second depending on the heat setting. It is completely normal and means the pump is working. On a low heat setting the click is slow and steady. On high heat it speeds up to a rapid clicking sound.
You can reduce how much you hear it by mounting the pump on a foam pad to dampen vibration through the van floor, and running the fuel line in gentle curves rather than sharp bends. Some people wrap the pump body in closed-cell foam. It will never be completely silent, but it becomes background noise after a few nights.
Altitude problems
Chinese diesel heaters start to struggle above around 2,000m (6,500ft). At altitude, thinner air means less oxygen but the fuel pump keeps delivering the same amount of diesel, resulting in a rich mixture. Symptoms are black or white smoke from the exhaust, soot build-up on the glow plug, failure to stay lit, or fault codes on the controller.
The fix is to reduce the fuel pump frequency in the controller settings — roughly 4% per 1,000ft of elevation. Better Bluetooth-equipped units (including the HCALORY and VEVOR Bluetooth models) can adjust this through the app. The Autoterm Air 2D does it automatically without any user input. If you do a lot of high-altitude driving, automatic compensation is worth paying for.
Glow plug maintenance
The glow plug is a consumable. Budget ceramic glow plugs typically last 1,000–2,000 hours before they need replacing. Better quality ceramic plugs can run 3,000–5,000 hours. A failed glow plug causes a no-start condition — the heater tries to light, fails, and throws a fault code. Replacement plugs cost USD $8–$25 on Amazon and take about 20 minutes to swap out.
Check the glow plug once a year. If it is soot-coated (common after high-altitude running or a rich-mixture episode), clean it carefully with fine sandpaper. A clean plug starts reliably every time.
Voltage drop causing no-start
The startup draw (8–12A for 30–60 seconds) combined with poor wiring is the most common electrical fault. If the wiring to the heater is undersized, or connections are corroded or loose, voltage sags below the minimum threshold during startup and the heater throws a low-voltage error. Wire direct to the battery with appropriately sized cable and a dedicated 20A fuse. Do not run it off a cigarette lighter socket or an extension lead.
Installation basics
Most van builds mount the heater inside the vehicle with the combustion intake, exhaust pipe, and fuel line all passing through the floor. You need to drill a hole through the van floor (typically 60–70mm for the mounting turret) in a spot clear of frame rails, brake lines, fuel lines, and wiring looms.
Key points for a clean install:
- Mount the fuel pump as close to the fuel source as possible. These pumps push fuel better than they pull it.
- Run the fuel line from the pump to the heater on a gentle uphill slope so any air bubbles travel toward the heater, not back to the pump.
- Route the exhaust pipe rearward and downward, well clear of the vehicle body. Never run exhaust toward any opening in the van.
- Keep the combustion air intake and the exhaust outlet on opposite sides of the vehicle. If they are close to each other, exhaust gas can get pulled back into the combustion intake.
- Seal every exhaust joint with exhaust putty and quality stainless clamps. A leaking joint is where CO gets in.
- Wire direct to the battery, not to a secondary fuse box. Keep cable runs short and use the correct gauge for the current draw.
The full electrical build guide covers where diesel heaters fit in the 12V system, cable sizing, and fusing. See the Van Electrical Build Guide for the complete install sequence.
Common questions
Can I run a diesel heater off my van's main fuel tank?
Yes, and it is the preferred option for a clean permanent install. The neatest method is to remove the fuel sender unit and add a dip tube through the sender hole — the heater's fuel line taps directly into the tank without any T-fittings in the supply line. The heater draws so little diesel (0.2–0.5 L/hr) that it has a negligible effect on your tank level. You can also use the supplied separate tank, which is simpler to install but requires refilling manually.
How much power does a diesel heater use from my battery?
Very little once it is running. Startup draws 8–12A for about 30–60 seconds as the glow plug heats up. Once combustion is established and the glow plug switches off, running draw drops to 1–4A depending on the heat setting. A 100Ah LiFePO4 battery can run a diesel heater overnight on a cold night with plenty left over for morning. It is one of the most battery-efficient ways to heat a van.
How long does a 5L tank last?
A 2kW unit running at moderate output uses roughly 0.2–0.25 L/hr. A 5L tank gives you approximately 20–25 hours of running time at that setting. At full output (colder nights) that drops to around 14–17 hours. If you tap the main van tank, runtime is essentially unlimited within your driving fuel supply.
Are Chinese diesel heaters safe?
When correctly installed, yes. The sealed combustion chamber means exhaust never enters the cabin under normal operation. The risk comes from poor installation — unsecured exhaust joints, fuel line damage, or a poorly sealed floor penetration. Fit a CO detector, use quality clamps and exhaust sealant on every joint, and inspect the installation annually. Those three things cover the main risks.
Can I run a diesel heater in a petrol van?
Yes. A diesel air heater runs on diesel fuel stored in its own separate tank — it has nothing to do with your van's engine fuel type. You fill the heater's tank with diesel from a fuel station regardless of whether your van runs on petrol, diesel, or LPG. The heater's fuel system is completely independent of the engine.
What is the difference between a 2kW and a 5kW body?
The physical heater body is different in size and maximum output. The 2kW body is smaller and tops out at around 6,800 BTU/hr. The 5kW body is larger and tops out at roughly 17,000 BTU/hr. All products sold as 3kW, 4kW, 6kW, or 8kW are the 5kW body with adjusted fuel and air settings in the controller software — there is no 3kW or 6kW physical body. If you see one advertised that way, it is a 5kW unit running at a restricted output level.
The recommendation
Budget: AU Focus (AU) or HCALORY (US). Full-time: Autoterm Air 2D.
For a budget van build in Australia, the AU Focus Gen 4 is the easiest choice. The local warranty and caravan industry backing make it worth paying a bit more than a generic unit. In the US, the HCALORY 2kW Bluetooth with the 2025 board is the most reliable budget option right now.
If you live in your van full-time or travel in cold climates regularly, the Autoterm Air 2D is worth the extra spend. It is quieter, handles altitude automatically, and will outlast a budget unit by a significant margin. The running cost difference over three to four years makes the upfront gap smaller than it looks.
Whatever you buy: fit a CO detector before the first use. It is not optional.