6 Best Diesel Heaters for Campervans & RVs | A Buyer’s Guide

Check out our brief introduction to diesel heaters for vans.

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Living in a camper during cold winter months would be unbearable without a way to keep warm.

Sure there are ways to keep warm in a van without a heater. But if planning to spend any length of time winter camping, it’s best to consider other options.

Heating for campervans comes in a variety of fuel types.

Energy efficient and with the ability to safely run all night in the worst of winters, 12v diesel heaters are considered by many, the best heating for RV living and van life.

But there’s a few available from top of the range brands like Webasto and Espar to cheaper and lesser known Russian and Chinese makes.

So what are the best diesel heaters for campervans, RVs and motorhomes? Read on!

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How do 12 Volt Diesel Heaters Work?

Diesel heaters are basically air heaters.

A heat exchanger coil is heated inside a combustion chamber. 

The heater draws in fresh cool air, passes it over the heated coil and blows out warmed air into your camper.

It’s that simple.

Why Choose a Diesel Heater?

Diesel heaters come with a few advantages that we think make them hands down the best options for heating a camper.

If your camper runs on diesel, you’re never going to be short of fuel. The diesel heaters can run directly off your main tank so there’s no need for separate storage for different fuel types. 

Diesel is cheap, readily available and because they’re so efficient, the running costs of a diesel heater are insignificant.

Anything that helps keep van life costs down is a good thing.

Heat from a diesel heater is a slow and steady waft of warm, dry air helping keep the van comfortable.

Because it has an external vent, it doesn’t add any moisture to the van and lowers the relative humidity. 

This is the perfect conditions for helping to prevent condensation in a van.

The external vent also helps minimise any chance of carbon monoxide build up, though we encourage you to install a carbon monoxide detector too.

Also read: Best Van Roof Vent for Your Campervan Conversion in 2022

Things to Look for when Buying a Diesel Heater for your Camper

Here’s a few different features and specifications to look out for when comparing diesel heaters. 

Heat Output

Buying the right size diesel heater is critical so you don’t waste money on an over or undersized component.

Too small, and the diesel heater will not efficiently heat your space, so use more electric and fuel than necessary, possibly still not keep you warm and run on the highest and noisiest setting.

Too big, you’ll spend a lot more money on the initial outlay. 

It’ll rarely need to run on full blast and more carbon will build up so it will need more regular maintenance. Add to that, it’ll cycle more often.

Diesel heaters are noisiest and use most electric when switching on and off so aim for a size to keep the cycles down.

The right size depends on how much space needs to be heated.

Remember overhead cabinets will reduce the space that needs heating, while removing the bulkhead into the driver’s cab will increase it. 

We suggest a 2KW heater power for medium sized vans. For anything larger, look for 4-5KW.

Altitude Setting

Diesel heaters can be problematic at high altitudes – anything above 5-6000 feet above sea level.

The top end models have features that change the mix of air & fuel so they still operate at higher altitudes.

Even with the high altitude kit, our Webasto struggled at 15000 feet above seal level in Bolivia but that was extreme altitude.

If you expect to spend time at high altitudes, look for a model with a feature or optional extras to allow them to operate.

Noise

Diesel heaters can be pretty noisy, especially if you’re trying to sleep. 

They make most noise on their highest settings and when going through their startup and shutdown cycles.

You can help reduce the startup by keeping the thermostat at a comfortable temperature and installing the right size heater for your van.

The top end models have features to minimise the racket they make. 

We have a Webasto in our Sprinter conversion and lived through a Patagonian winter.  It never disturbed us and we had it running round the clock.

Electrical Demand

Diesel heaters need a 12v electrical supply to get going. They demand a surge of power on start up and shutdown and a trickle when in use. 

While not a disadvantage, it’s worth bearing in mind that the initial start up takes a good surge of power. From cold, this can be as much as 15 amps. 

They don’t draw this for long and within a few seconds, ours drops to 3 or 4 amps for another 5 minutes or so.

Once it’s warm, it runs at around 1 amp per hour.

Make sure you take this into consideration in your solar battery bank calculation.

Some diesel heater brands have models for both 12v and 24v batteries. All the models in this article are the 12v versions.

Maintenance

Diesel is quite a dirty fuel so the heaters can suffer with a build up of carbon over time. To prevent this, give the heater a run for an hour at full blast at least once a month. 

Otherwise, follow the manufacturer’s maintenance and cleaning routines to help keep it in tip top order. 

Fuel & Efficiency

Diesel heaters use diesel, of course, though the top end models now also have petrol versions of their products.

The efficiency is fantastic and incredibly low on all diesel heaters. 

Some are slightly better than others and depending on the settings us around 0.1 and 0.5 litre per hour.

The cost of running a diesel heater in a camper is really low compared to other heating options.

Cost

The top end models have a high cost, especially compared to a comparable Propex gas heater.

But if budget is critical at this stage of your DIY campervan conversion, the low end Russian and Chinese models are much, much cheaper.

And the price difference is so big that if you have the budget later for the higher end brands, swapping them out is relatively straightforward and you won’t feel you’ve wasted much.

Reliability & Servicing

The top end brands of Webasto and Espar have a proven track record when it comes to the quality of the build and reliability of the product.

Though at the prices they’re charging, you’d expect that at the very least.

If you have any warranty claims or servicing issues, they both have a fairly good coverage of service centres across Europe and North America. 

The budget models have no such track record or service centres. You are pretty much on you own when it comes to finding advice or servicing.

The budget models have become so popular though there’s a growing Facebook group where there’s loads of advice and support for dealing with common problems.

With so many people are using them completely issue free now and with a growing number of customers, we’d definitely consider them in future campervan conversions. 

Webasto STC2000 & Air Top Evo 40

Along with Espar, Webasto is one of the 2 top end diesel heater brands for campervans, RVs and boats.

They produce high quality and reliable components and have a network of service centres and dealers, especially in Europe.

The most common heaters for campervans are the STC 2000 & Air Top Evo 40.

Heat Output

The STC 2000 is best suited for campers upto medium sized and the Air Top Evo 40 for larger RVs.

We have an STC 2000 installed in our long wheel base Sprinter conversion.

Because we have no overhead cabinets, we have quite a lot of space to heat. 

Though it served us well during a Patagonian winter, if we were to do the conversion over again, we’d opt for the Air Top Evo 40.

Altitude Setting

If you plan to spend time at high altitudes, anything over 2000 metres on both models might work well.

The Air Top Evo 40 has an in-built altitude sensor and the spec states it’ll work upto 5500 metres.

The STC 2000 specification is a little more vague when committing to the altitude it works to. Ours has an altitude boost on the control panel.

But that only really worked well upto about 2500 metres.

After that, a manual, electrical adjustment is needed which is really fiddly. It’s not ideal if your altitude changes frequently.

Electrical demand

Both Webasto models run on a low amps so you’ll barely notice any drain on your campervan batteries.

Remember though, they need a bigger surge to start from cold.

If possible, keep the start cycles to a minimum by maintaining a comfortable temperature all the time.

Use our electrical calculators to help size your solar setup.

Fuel consumption

As expected from a diesel heater, the fuel consumption is really low.

On the lowest setting, the STC 2000 will use less than 3 litres in 24 hours of constant running.

Cost

Webasto products, like Espar’s, carry a high price tag.

But as with most things in life, you get what you pay for. 

With Webasto diesel heaters, the price tag buys a high quality, well-built product with an excellent track record and reputation. 

Espar Airtronic D2 & M2

Along with Webasto, Espar is the other top end diesel heater brands for campervans, RVs and boats.

They produce high quality and reliable components and have a network of service centres and dealers.

The most common Espar heater for campervans is the Airtronic D2 though the M2 matches the Webasto Air Top Evo 40 for heat output.

Heat Output

The Espar Airtronic D2 is best suited for campers upto medium sized and the Airtronic D2 for larger RVs.

Consider how much space you have to heat. Even on a medium sized camper, if you have no overhead cabinets  or bulkhead between the drivers cab and living cabin, you may need the larger size to keep that space warm.

Both Espar models provide a greater heat output that their Webasto alternatives.

Altitude Setting

The Espar D2 is guaranteed to work upto 1500 metres above sea level. 

For extended periods spent upto 3000 metres, a high altitude sensor or pump kit is needed.

The altitude sensor measures atmospheric pressure, automatically adjusting the frequency of the metering pump every 300m of altitude increase.  

The high altitude pump kit is a cheaper option but more manual. You need to install a 2nd pump and manually set the pump to use.

You can switch between the 2 when you change altitude but it’s not the most elegant solution.

Electrical demand

Both Espar models run on a low amps. At full power, they’re a little more thirsty than the Webasto but on lower power, they have a slight advantage.

As with all diesel heaters, they need a bigger surge to start from cold.

If possible, keep the start cycles to a minimum by maintaining a comfortable temperature all the time.

Use our solar battery bank calculator to help size your solar setup.

Fuel consumption

Fuel consumption is really low on the Espar diesel heaters too.

On the lowest setting, the Airtronic D2 will use less than 2.5 litres in 24 hours of constant running.

Cost

Espar’s products carry a high price tag, though they tend to be slightly lower cost than Webasto.

Even so, they don’t cut corners on quality and in terms of reliability, Espar’s are on a par with a Webasto.

Now bear with us here and try not to be immediately put off by these Chinese or Russian imports.

We wouldn’t normally consider a low end product for our camper conversion but these have a growing fanbase.

There’s many, many “brands” available. 

Just search for 12v diesel heater on Ebay. You’ll find brands like Planar, Snugger, Ambienceo, Happybuy and many more unbranded options.

For a component that if not installed correctly could have catastrophic consequences, this sounds like a reason to steer well clear.

Except these components are less than 10% of the price of a Webasto or Espar. So over the years, converters have tried and tested them out so that today, there are thousands of campervans the world over with these things installed.

As you might expect from unbranded products, warranties don’t exist – or at least not ones worth the paper they’re written on.

Operating manuals and installations instructions can be absent or written in Chinese and you won’t find a service centre on this planet.

But there’s a dedicated Facebook Group of likeminded customers, all who have or are considering installing a low cost alternative to the Webato and Espar models.

Some installation issues occur but because so many people have now installed them, most common issues are well understood.

If you experience an issue, 9 times out of 10, you’ll find someone on the group who has also experienced it and has a suggested solution.

So with specifications comparable to the Webasto and Espar diesel heaters, and coming in at a fraction of the cost we think you should at least consider these as a potentially viable alternative.

It’s hard to come out with an outright winner for the best of all the diesel heaters for campervans. 

As with so many parts of campervan conversion and van life, it really depends on your intended use and budget.

• If you want something cheap, choose a budget Chinese or Russian model
• For travelling in your camper at altitudes above 3000 metres, choose a Webasto Air Top Evo 40
• The best value, high end diesel heater in the Espar Airtronic D2

If you want to boondock in winter, check out our other tips on how to heat a camper without electricity.

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