The Best Caravan Diesel Heater Guide For 2026 : What Size You Need, Running Costs & Our Top Picks

When you are planning your next Big Lap or a quiet weekend getaway, keeping the van warm on a frosty morning is what separates a good trip from a miserable one. A diesel heater is one of the most practical heating solutions you can fit to a caravan and for anyone chasing comfort through a Victorian High Country winter or a cold desert night out the back of Broken Hill, it has become close to standard kit.

This guide covers what matters when choosing a diesel heater: popular sizes and brands, installation, safety, maintenance, battery setup, and the most common questions we get at CARAC.

3 Reasons To Choose a Diesel Caravan Heater

Diesel heaters have quietly taken over from gas as the go to heating option for serious caravanners with good reasons for that shift.

1. Efficiency and dry heat

Caravan diesel heaters pull combustion air from outside the van, burns it in a sealed chamber, and vents the exhaust back outside through the floor. Only clean, warm air is pushed into the living space.

Because the combustion is fully sealed, you do not get the moisture that gas heaters tend to release inside the van. That means less condensation on the windows in the morning, drier bedding and far less chance of mould creeping into the corners after a week of cold-weather touring.

2. Low running costs and fuel availability

Diesel is cheaper than bottled LPG on a per-hour basis once you factor in how efficient these units are. Running a 2kW heater on a low to medium setting burns roughly 0.13 to 0.24 litres an hour, so an overnight run of ten hours costs you somewhere between two and five dollars at the pump.

That is noticeably less than an equivalent gas heater, which is one reason caravanners on long trips tend to favour diesel. Every servo from Port Augusta to Cape York stocks diesel, but LPG swap and go gets scarce once you head out along the Oodnadatta or into remote country. With diesel, you can top up from the same jerry can you carry for the tow vehicle.

The table below breaks down what that looks like in dollars and cents based on the current Melbourne average diesel price of $3.18 per litre (sourced from PetrolSpy, April 2026).

Heater Size & Setting	Fuel Use (L/hr)	Cost per Hour	10-hr Overnight	7-night Trip (70 hrs)	4-week Leg (280 hrs)
2kW on Low	0.13	$0.41	$4.13	$28.94	$115.75
2kW on Medium	0.20	$0.64	$6.36	$44.52	$178.08
2kW on High	0.30	$0.95	$9.54	$66.78	$267.12
5kW on Low	0.16	$0.51	$5.09	$35.62	$142.46
5kW on Medium	0.35	$1.11	$11.13	$77.91	$311.64
5kW on High	0.55	$1.75	$17.49	$122.43	$489.72

Based on the Melbourne metro average diesel price of $3.18 per litre (PetrolSpy, April 2026). Regional Victoria and outback servos often sit 10 to 30 cents higher per litre. Actual costs will vary with fuel price, ambient temperature, caravan insulation, and how hard the unit has to work to hold your set temperature.

Worth noting: most travellers run their heater on low to medium overnight, with the thermostat cycling the unit on and off as needed. Real-world fuel use tends to sit closer to the low setting figures than the high ones, so budget around $4 to $6 a night for overnight heating in a typical Victorian winter.

3. Safety and installation flexibility

Diesel is far less volatile than LPG. A diesel line leak pools as a liquid; an LPG leak expands to fill the cabin and creates a genuine explosion risk. Diesel heaters also produce lower carbon monoxide concentrations when properly maintained and the unit itself runs cool to the touch.

Gas heaters must be fitted by a licensed gas fitter in Australia and need a flue through the wall. Diesel heaters exhaust through the floor, which gives you far more placement options and means a competent DIYer can fit one over a weekend.

Professional installation is still recommended to protect the warranty.

5 Key Factors When Choosing the Best Diesel Heater for Your Caravan

Before picking a model, run through these five considerations. They will save you from buying the wrong unit.

1. Caravan size and insulation quality

The shape and insulation of your van matters as much as the length. A well insulated composite van with double glazing will hold heat much better than a single skin pop-top of the same length.

As a rough guide:

• Camper trailers and pop-tops with minimal insulation: 2kW is enough for vans up to around 4.9 m
• Standard caravans with moderate insulation: 2kW is fine up to about 6.7 m, step up to 5kW for anything 6.7 m to 9 m
• Well-insulated vans with composite walls: 2kW will comfortably handle lengths up to 8 m

2. Heater placement

Most installers fit the unit under a bed, dinette seat, or in an external storage locker, close to the fuel tank and a 12V supply. Keep a minimum 50 mm clearance from any combustible surface, and avoid long duct runs.

3. Fuel consumption

Fuel use varies with setting, not just heater size. A 2kW unit typically uses 0.13 to 0.30 L per hour.

A 5kW unit uses anywhere from 0.16 to 0.55 L per hour depending on how hard it is working. This matters because it directly affects how long your fuel tank lasts off-grid.

4. Electrical draw

Every diesel heater pulls a burst of current during the two minute startup cycle while the glow plug heats up, then settles into a low running draw. Typical figures sit at 8 to 12 amps on start up and 0.5 to 2.5 amps during normal running. Your battery and wiring need to cope with the peak draw without voltage sag, which we cover in more detail further down.

5. Noise

A diesel heater makes two sounds: the fan, and the tick of the fuel pump. Quality units are surprisingly quiet, but budget models can have a pronounced pump tick that keeps light sleepers awake. Mount the fuel pump on a rubber isolator and place it away from the bed head.

2kW vs 5kW Diesel Heater Units: Which Is Better?

This is the single most asked question from customers looking for a heater. The short answer is that it depends on your van, your insulation, and where you camp. The longer answer is more useful.

The oversizing advantage

A 5kW heater running at 40 per cent load to heat a medium sized van is usually quieter and more fuel-efficient than a 2kW heater running flat out to do the same job. At lower settings, the fuel pump cycles less often, the fan spins slower, and the unit uses less power overall. That is counterintuitive, and it is the opposite of what most people assume when they see the larger kW rating.

Noise comparison

A 2kW heater at full output sits around 45 to 55 dB, roughly the level of a normal conversation. A 5kW heater producing the same heat at 40 to 50 per cent load runs at about 35 to 42 dB, closer to a quiet library. If you are a light sleeper, this matters.

2kW is best for smaller caravans

A 2kW diesel heater suits pop-tops, campers, and standard caravans up to around 7.3 m. It produces steady, comfortable heat without overwhelming a small cabin, and it uses less fuel on average when matched to the right-sized space. The main drawback is that it has to work harder in cold conditions, which means more noise and more fuel use at the top end.

5kW is best for larger caravans

A 5kW unit suits vans longer than 7.3 m, slide-outs, canvas-sided campers, and anyone who regularly camps in sub-zero conditions. It spends most of its life on low settings, which actually saves fuel and makes it quieter. The catch is that it can cycle the cabin temperature too quickly in a small space, leading to a warm then cool pattern that is uncomfortable.

Alpine and cold-weather considerations

If you do a lot of camping in the Victorian High Country, the Snowy Mountains, or the Tasmanian central highlands, where overnight lows can drop below minus five degrees, size up.

A 2kW unit that is fine at five degrees ambient will struggle when it is minus eight outside. A 5kW gives you headroom without running flat out all night.

Top Diesel Heaters On The Market In 2026

Here are the two heaters we recommend most often at CARAC, one at the budget end and one at the premium end.

1. AU Focus Caravan Bluetooth Diesel Heater 12V 2kW Includes Tank, $749.00

The AU Focus Bluetooth 12V 2kW is the unit we sell the most of, and for good reason. It is Australian supported, which means replacement parts and after-sales help are a phone call away, not a slow shipment from overseas.

Key specs and features:

• 2kW heat output on 12V
• Bluetooth control via smartphone, plus a physical controller
• Two temperature sensors for accurate cabin temperature control
• Upgraded wiring loom on the Gen 4 (2026) model
• Fuel consumption around 0.13 to 0.30 L per hour
• Includes a fuel tank in the kit

Why choose it: excellent value for a fully featured 2kW unit, backed by Australian support. A smart choice for first-time buyers and for smaller vans up to around 7 m.

2. Webasto Air Top 2000 STC Single Outlet Standard Control, $1,649.00

The Webasto Air Top 2000 STC is a premium German-made unit that has been around the marine and RV world for decades. If you are doing a lot of remote touring and you want something that will last fifteen years without drama, this is it.

Key specs and features:

• 2kW heat output on 12V
• Single outlet for a clean, simple install
• Very quiet operation at low settings
• Fuel consumption around 0.17 to 0.28 L per hour
• Built for continuous use with low maintenance requirements

Why choose it: top-tier build quality, quiet operation, and a reputation earned on boats in rough conditions. Worth the price jump if you are outfitting a van for long-term touring.

Heater Side-by-side comparison

Specification	AU Focus 2kW (Gen 4)	Webasto Air Top 2000 STC
Heat output	2.0 kW	2.0 kW
Fuel consumption (low to high)	0.13 to 0.30 L per hour	0.17 to 0.28 L per hour
Startup power draw	8 to 10 A	8 to 10 A
Running power draw	0.5 to 2.0 A	0.8 to 2.5 A
Noise at low setting	around 38 dB	around 40 dB
Operating temperature range	minus 40 to plus 40 degrees	minus 40 to plus 40 degrees
Bluetooth control	Yes	No (optional upgrade)
Approximate weight	2.7 kg	2.8 kg
Price (AUD)	$749	$1,649

 

Both units weigh under 3 kg, which is negligible against your caravan's ATM (Aggregate Trailer Mass) and payload. Even once you add a 10 L fuel tank, ducting, and fixings, the full install adds less than 15 kg to your Tare Mass, so it rarely causes a payload headache.

Diesel Heater Installation Tips

A diesel heater install is not difficult, but a bad install causes ninety per cent of the problems we see in the workshop. Get these basics right.

Location. Pick a spot near an external wall, close to the fuel tank, with clear access to a 12V supply. Under a bed or bench seat is popular. Avoid locations where you cannot get to the unit for servicing.

Exhaust routing. The exhaust exits through the floor pointing down and away from any vents, windows, or entry points. Keep at least 50 mm clearance from the ground and make sure it is not going to get blocked by grass or mud when you park on soft ground.

Fuel line. Route the fuel line away from the exhaust pipe so it is not exposed to heat. Use diesel rated fuel line, never clear PVC. Keep the run as short as practical and avoid sharp bends or kinks.

Combustion air intake. The intake must pull fresh outside air, not recirculate exhaust. Keep the intake and exhaust separated so there is no chance of cross-contamination.

Electrical. Use a minimum 6 mm squared cable from the battery, with an appropriately rated inline fuse. Keep the run short to minimise voltage drop. Diesel heaters can throw error codes and fail to start if the supply drops below 10.5 V during the startup draw.

Ducting. Insulated ducting helps deliver heat to the far end of the van without losing it to the underfloor area. Keep duct runs as short and straight as possible.

If any of this feels beyond your comfort zone, book in with a qualified caravan workshop. A professional install usually takes a day and protects your warranty.

Safety Considerations for Diesel Heaters

Diesel heaters are one of the safer cabin heating options you can run, but safety still depends on proper installation and regular checks for wear and tear and heater parts requiring replacement.

Carbon monoxide detection

Fit a carbon monoxide alarm inside the living space, rated to AS 2171. Mount it at roughly breathing height near the sleeping area, and test it before every trip. If the heater ever produces visible smoke or a strong exhaust smell inside the van, shut it down and ventilate straight away. That points to a combustion or exhaust seal failure that needs attention.

Exhaust placement

The exhaust outlet must point away from air intakes, windows, and any annexe openings. When parked on grass or soft ground, check the exhaust is not buried or blocked. If you run an annexe, make sure the heater exhaust does not vent under the awning skirt where it could build up.

Altitude safety for Australian alpine areas

Once you climb above roughly 1500 m, the thinner air starts affecting combustion. You get incomplete burn, more carbon build up, and higher carbon monoxide output. Most of our alpine destinations sit below that threshold, but the summit of Mount Kosciuszko road, some Falls Creek sites, and parts of the Tasmanian highlands push into this zone.

Common installation errors to avoid

• Exhaust and combustion air intake mounted too close together, causing recirculation
• Fuel lines routed next to the hot exhaust pipe
• Undersized wiring causing voltage drop on startup
• Using non-diesel-rated fuel line that cracks over time
• Inadequate clearance from combustible materials

Ventilation

Even though diesel heaters do not burn cabin air, you still need ventilation inside the van for fresh air exchange and to manage the moisture you produce yourself from breathing and cooking. Keep at least one high and one low vent open, even on the coldest nights.

Fire safety

Keep a small fire extinguisher and a fire blanket within reach of the cooking area. Never stow flammable items such as clothing or bedding directly against the heater or its ducting.

Diesel Heater Maintenance Guide

Most diesel heater failures come down to two things: carbon build up on the glow plug, and dodgy fuel. Both are preventable with a simple routine.

Monthly during heating season

Run the heater on maximum output for fifteen to thirty minutes at least once a month. The high combustion temperatures burn off carbon deposits on the glow plug screen and keep the combustion chamber clean.

Skipping this step is the number one cause of the dreaded failed-to-start error code.

Annually or every 500 hours

• Remove and inspect the glow plug, clean or replace the mesh screen if crusted
• Replace the inline fuel filter
• Check the combustion chamber with compressed air or a soft brush
• Inspect fuel lines for cracks or kinks, especially after a corrugated-road trip
• Check the exhaust clamps for corrosion and tightness

Glow plugs typically last one to two seasons of regular use. A replacement glow plug costs between thirty and eighty dollars depending on the brand, and it is a fifteen-minute job.

Fuel quality for Australian conditions

Always use clean diesel from a reputable servo. Contaminated fuel is the fastest way to kill a heater. If you store diesel in a jerry can for more than three months, add a fuel stabiliser. In sub-zero alpine conditions, a small amount of diesel anti-gel additive stops the fuel waxing, which can otherwise block the fuel filter around minus six to minus ten degrees.

Service intervals by brand

• Webasto: roughly every 1500 hours
• AU Focus and most Chinese-manufactured units: 500 to 1000 hours, with more frequent glow plug checks

Battery and Solar Requirements for Diesel Heaters

This is where plenty of off-grid setups come unstuck, so it pays to match the heater to your electrical system.

Startup vs running draw

A 2kW heater pulls roughly 8 to 12 amps during the two-minute startup while the glow plug heats, then drops back to 0.5 to 2.5 amps while running. Your battery and wiring need to handle the peak without the voltage dropping below 10.5 V.

Overnight battery consumption

A 2kW heater on a low to medium setting for ten hours uses about 10 to 20 Ah. On a 200 Ah lithium bank, that is five to ten per cent of capacity, barely a dent.

On a 100 Ah AGM (with around 50 Ah usable capacity), that is 20 to 40 per cent of what you actually have, which is still workable for a night but leaves less margin.

Minimum recommended battery setup

• Single 100 Ah lithium: enough for overnight heating plus fridges and lights
• Single 100 Ah AGM: adequate for one night, marginal for consecutive off-grid nights without solar
• 200 Ah or larger lithium bank: comfortable for multi-night off-grid touring

Solar sizing

A 200 W solar panel in an Australian winter generates roughly 50 to 80 Ah per day, which comfortably replaces what the heater uses overnight and charges the rest of your 12V load. If you are regularly shaded or camped under cloud, step up to 300 W or more to keep a buffer.

Wiring

Stick to 6 mm squared cable or heavier for the heater supply, and keep the run short. An inline fuse sized to the manufacturer spec protects the wiring and the heater electronics.

Alternatives to Consider: Gas, Air Conditioning and Portable Caravan Heaters

Diesel is not the only option. Here is where each alternative still earns its place.

Gas heaters for caravans

The Truma VarioHeat Eco at $2,149 is our most popular gas unit. It can be fitted vertically or horizontally, runs at either 1300 W or 2800 W, and has a boost mode plus a quiet night mode. Gas suits travellers who already carry a large LPG setup for cooking and hot water, and who do not venture into remote areas where refills are scarce. The catch is the licensed gas fitter requirement for installation, and the condensation gas heating brings into the cabin.

Portable diesel heaters

The Portable Diesel Heater 2kW at $629 is a ripper option if you do not want a permanent install, or if you move between multiple vehicles. It includes a built-in 5 L tank, runs on a 12V battery, and comes with smartphone control. Ideal for weekend campers, 4WD tourers, and anyone who wants flexibility without committing to a fit-out. The only real downside is that you have to store it safely while travelling.

Reverse-cycle air conditioners

Rooftop and under-bunk reverse-cycle units deliver both heating and cooling from the same unit, which is genuinely useful for year-round travel across Australia's climate range. We stock the Truma Aventa Comfort, the Truma Saphir, and the Finch Australia Houghton 3400. The tradeoff is power draw: these units really need 240V mains or a big inverter setup, so they shine in caravan parks and struggle off-grid.

Frequently Asked Questions

How much diesel does a caravan heater use per night?

A 2kW diesel heater on a low to medium setting uses roughly 0.13 to 0.24 L per hour. Over a ten-hour overnight run, that is about 1.3 to 2.4 L of diesel, or around two to five dollars at current pump prices.

Can I run a diesel heater all night in my caravan?

Yes. Diesel heaters are designed for continuous operation and are safe to run overnight provided you have a working carbon monoxide alarm, the exhaust vents externally, and you have enough fuel and battery capacity. Most units cycle automatically via the built-in thermostat.

Will a diesel heater drain my caravan battery?

Not significantly. Expect 10 to 20 Ah of battery use over a ten-hour night. A 200 Ah lithium battery handles this easily. A 100 Ah AGM is fine for a single night but will need solar or alternator recharging between nights.

Do diesel heaters work at high altitude in Australia?

Standard heaters work reliably up to about 1500 m elevation. Above that, you may see incomplete combustion and smoking. Most Aussie alpine campsites sit below 1500 m, so it is only an issue in specific spots.

Is a 2kW or 5kW heater better for my caravan?

For most caravans under 7.3 m with decent insulation, a 2kW is the right call. For vans over 7.3 m, canvas-sided campers, or anyone regularly camping in sub-zero conditions, a 5kW is the better pick, and it is often quieter at partial load.

Do I need a licensed installer for a diesel heater?

No, unlike gas heaters, diesel heaters do not require a licensed gas fitter. DIY installation is legal and common, though professional installation is recommended for warranty purposes and peace of mind.

How often should I service my diesel heater?

Run it on high for fifteen to thirty minutes once a month during the heating season. Do a full annual service or every 500 hours, including glow plug inspection, fuel filter replacement, and combustion chamber cleaning.

Final Thoughts

Diesel heaters have earned their place in the Australian caravanning world because they do the job reliably, cheaply, and without adding moisture to the cabin. For most travellers, the AU Focus Caravan Bluetooth Diesel Heater 12V 2kW offers the best balance of price, features, and Australian-based support. If you are kitting out a van for heavy use over many years, the Webasto Air Top 2000 STC is worth the extra investment for its build quality and longevity.

Whichever unit you choose, get the install right, fit a carbon monoxide alarm, and run it hot once a month. Do those three things and expect years of warm, quiet nights.

>> Shop All Diesel Heaters Online at CARAC <<