A Diesel heater; the ultimate upgrade for cold camping

It’s funny how camping has changed over the years. The idea of having a diesel heater for your caravan, camper trailer, RV or tent would have been ridiculous a few decades ago, but yet here we are.

Diesel heater installations have exploded over the last few years, and there’s a number of very good reasons that have contributed to this.

Diesel heaters are now extremely common in the RV and camping industry, as well as off grid living, and anyone with a basic understanding and some tools can purchase, install and run one without much effort at all.

Caravan diesel heater
Diesel heaters are cheap, easy to install and incredibly efficient
Diesel heater display
Press a button on a remote and you get virtually instant heat without 240V power

We actually purchased a Portable Diesel Heater a few years back, and have been really happy with its performance. The more common option though, is a permanently mounted diesel heater, which we cover below. Obviously there are quite a few similarities, and they will suit different people and applications!

Portable Diesel heater
Our portable diesel heater, pumping warm air into our Reconn R2

What is a diesel heater?

If you’ve not had much to do with diesel heaters in the past, they are actually pretty simple. In essence, they are a small heat exchanger, and a fan. Diesel is burnt inside a chamber, and a small fan pushes air through the heat exchanger next to it, with it being warmed up by the transfer of heat.

It’s important to note that the air being heated does not come in contact with the combustion process; its purely a transfer of heat taking place which makes them very robust and safe.

This warm air continues its journey out of the diesel heater, and into your boat, caravan, tent, camper trailer or what ever else you choose to run. Of course, there’s an exhaust, which needs to be appropriately routed so you stay nice and safe.

Diesel heater installation
They are simple, easy to install and work well

Why are they so good?

There’s a lot of reasons diesel heaters are so highly raved about:

The heat output is incredible

For camping applications, most people buy between 2 and 5kW heaters. The heat output is similar to that of a normal electric fan heater, and in a small space (tent/camper trailer/caravan) it warms the area up incredibly fast, and keeps it that way.

Obviously, the warmth inside your sleeping quarters depends not only on the heat generated by the heater, but by how well you can keep it in. A canvas camper trailer is going to retain a lot less heat than a caravan will, and the better insulation you have the less heating you’ll need.

Reconn R2 diesel heater
Even on a freezing night in the middle of no where you can be toasty warm

They are cheap to buy and run

There are a couple of ‘original’ diesel heaters on the market that are quite expensive, but these days a diesel heater can be purchased for $100 – $350. Of course, there are still expensive ones, and mid range units, but in general they are very economical to purchase.

Beyond this, they are cheap to run as well. I roughly did the calculations and I reckon the running costs are similar to that of running a fan heater at home in Perth, at 29 cents a kwh. You can comfortably run one overnight and only use 1 – 2 litres of diesel, which is pretty good value.

Diesel tank
A bit of diesel, a 12V supply and you are good to go!

Installation is relatively easy

There’s nothing overly complicated about diesel heaters. They need a 12V supply, an exhaust mounted out of the way, small fuel pump, ducting for the hot air, diesel tank and inlet to your setup.

There are some small tricks to get it quiet and working well, and you need to be careful how the exhaust is done so you don’t melt anything, but they are easy enough to install. Just make sure it is done properly; no shortcuts!

You can pay for a caravan diesel heater installation if you don’t want to play with it, but many people install it themselves.

In general the tank is mounted well away from the diesel heater, with the heater itself inside your van, and the exhaust coming out through the floor (with enough clearance). The ducting from the heater runs to a little vent that you can angle, and some people tee it off so you have hot air coming out two locations.

The fuel pump is normally mounted outside the van, near the heater and angled so it doesn’t have to work as hard to pump the fuel to the heater. The combustion air intake is also usually outside, with the air intake for the heater (the air that actually gets warmed) inside the van at the back of the heater.

Diesel heater installation
Diesel heaters are easily within most DIYers reach

You can run them off grid without a major setup

Perhaps the best thing about a diesel heater is that you can run it off grid, very easily. They draw around 10 amps on start-up for a minute or two, when the glow plugs are on, but then ramp down to 1 – 2 amps. This means you can comfortably run them off a normal 100aH deep cycle battery and a bit of fuel anywhere.

You can be in the middle of the bush, and have a toasty warm camping setup thanks to a diesel heater, and that is a game changer! There’s no need for a 15k lithium battery, solar and inverter setup to run your aircon for a few hours at a time; pretty much any basic camping setup will have the ability to run a diesel heater with limited fuss.

If you’ve ever looked at running a 12V heater, you’d conclude very quickly that a diesel heater is the ultimate, off grid arrangement.

They are quite small

Diesel heaters are relatively compact, especially when you permanently mount them, and spread things out. You can mount them in so many different ways, with lots of freedom to change things around to suit your individual setup, which means they are flexible in terms of installation.

You have the tank, fuel lines, fuel pump, heater unit, exhaust, ducting between the heater and your vents and a small controller.

Diesel heater size
The actual diesel heater is quite compact

Common diesel heater installations

Caravans, RV’s and Boats are probably the most common diesel heater installations. However, I have seen them in houses, soft floor camper trailers, roof top tents, cars (setup to sleep in) and even normal tents. Some of these lend better to a portable diesel heater setup, but there’s lots of ways to go about it.

Diesel heaters and safety

When a diesel heater is installed correctly, and running as it should they are very safe. However, it is possible for people to install them incorrectly, or for an internal failure to occur. Both of these scenario’s can create a deadly environment within the room you are trying to heat, and sadly people have passed away.

The solution is to ensure its installed correctly, and that there is no way the exhaust fumes can be sucked into your air stream. The second (and imperative) thing is to purchase a CO monitor.

You can get them from Bunnings and most camping stores for under $45 and they last for several years. It’s a no brainer, and they will alert you if anything is wrong.

You cannot see, or smell CO, but it can kill you in high concentrations; its just not worth the risk.

Quell CO monitor
You should get a CO monitor if you have a diesel heater; its cheap insurance

Be very cautious of the exhausts heat too; if you have an installation where these go through the floor without a larger metal shroud to dissipate the heat properly, you could end up with a nasty fire going on.

What do you need to know about Diesel heaters?

They can be noisy

If you’ve never heard a Diesel heater before it can be quite a shock. They are quite noisy on start-up, and then when running you’ll have the ticking of the fuel pump. Start-up only lasts for a couple of minutes, but it sounds like an aeroplane flying overhead from a distance as the fan really ramps up.

Once its running, the fans are fairly quiet unless you have them cranking at maximum, and you’ll just hear the fuel pump ticking as it moves diesel to the heater. If these are mounted correctly (fuel tank above the pump, angled correctly and isolated slightly) it is much better, but the ticking can still be annoying for people.

They require decent cables for start-up

Diesel heaters draw about 10 amp hours during start-up, to power the glow plugs. This means you need a decent battery, and cabling to get it going.

If your cable is too thin you’ll have big voltage drop and the heater will fault out. The high power draw is only for a couple of minutes, and then it backs off to 1 – 3 amp hours just to run the pump and fan.

Diesel heater temperature
Diesel heaters draw a decent amount of current on startup

They should be run flat out before turning them off

One of the issues with people buying diesel heaters that are oversize is that they run on a low setting for most of their life. This can cause carbon to build up and causes you a problem in the future. You are better off with a smaller unit that runs at a higher speed than a big unit just idling.

Either way, when you are ready to turn the heater off run it on full bore for a couple of minutes to get it really warm, and to burn any carbon away.

Where to buy a diesel heater

The most common place for people to buy the imported versions today is eBay, Alibaba or Amazon. If you want a brand name unit though, you’ll have to go directly to the supplier or their distributors. 

Eberspacher and Webasto are the two most well known units that cost about 5 – 10 times the price of a Chinese Diesel Heater off eBay, or Amazon.

There are some middle ground quality units which are still made in China, but sold in Australia by Australian owned businesses. Of course they will tell you that the cheap Chinese units are rubbish, and that you should buy something better quality.

The fact remains that there are thousands of cheap Chinese Diesel heaters out there that are running just fine, and there’s more than enough information to help you diagnose and repair them as needed.

If you need to replace them, you can go through several before the cost of a new, top quality unit is approached. 

What quality level you buy should reflect your own situation; if your life depends on a good diesel heater then perhaps don’t buy the cheapest one out there. If you are like many people in Australia though, who just want to keep warm for a handful of nights a year when they are out and about, the cheap units work just fine.

That said, do your own research and buy something that others have used, and recommend!

Chinese diesel heaters vs originals

So, you’ve committed to buying a diesel heater and want to know whether its worth paying a premium for a brand name, or just getting a cheap eBay unit? That’s entirely up to you, and depends on your purchasing style.

I personally know a number of people who have been running cheap diesel heaters for many years without any issues, and ours has been great too. They are easy enough to repair, cheap enough to replace and if you have technical issues there is an amazing Chinese Diesel Heaters Facebook Group with more information than you could poke a stick at.

As above, if you rely on your heater for survival, or you plan on using it heavily for many years it might be a different story, but only you can answer that.

What size diesel heater?

Sizing your diesel heater requires a bit of careful consideration. The smaller the area you are trying to heat, and the better insulated it is the smaller heater you can get away with.

Now, its important to note that there are only 2kw and 5kW diesel heaters, and many of them are incorrectly labelled. 5’s are often sold as 2’s, and vice versa. You’ll also get 5’s sold as 8kW, but in reality they don’t exist.

To give you an example, a mate of mine bought the same heater as us (a 5kW eBay job). He runs his in a 20ft caravan, and we run ours in our Reconn R2.

Within 30 minutes of running his unit it has to be turned off as the van is getting too warm. Our Hybrid on the other hand needs it to run on low (or a couple of settings up if its cold) all night to keep it comfortable.

Nannup caravan park
On a freezing night a diesel heater is seriously appreciated

His van retains the heat significantly better than our pop top. I suspect we might both get away with 2kW units, but we’d need a permanently mounted one as we lose a lot of energy with it being portable.

If you want to ensure you are getting the right size diesel heater, its actually really simple. A 5kW heater is around 38cm x 13.5cm x 13.5cm, with a 7.5cm outlet. 

A 2kW heater is only 32.5cm long x 11cm x 11cm, with a 6cm outlet. If you double check the actual heater dimensions you’ll get a good idea of whether its correctly advertised.

Diesel heater specifications
Don’t always believe how the heater is advertised

Diesel heater vs gas heaters

If you don’t have access to a significant 240V supply (as in as soon as you are away from a power point!) there are really only two substantial options for heating. Diesel, and Gas. The latter is common, but not nearly as much as a diesel heater. 

You can get gas ducted systems, which run off your LPG bottles that you already carry, and you can get hot water/air gas heaters in a combo, which have the ability to heat your water up and warm your van.

Both are good, and some people rave about gas heaters. However, they are significantly more expensive than a Chinese Diesel Heater, they require a certified gas fitter to do the installation and its much harder to get gas than it is to get diesel (which most people carry for their vehicles anyway).

Diesel heater tank and cover
A diesel heater tank on the front of a caravan, with a cover on it

Gas heaters also produce more moisture, and will use a lot more fuel than the equivalent diesel heater, simply because of the difference in energy between the two fuels. Couple this with the fact that most people don’t carry more than two 9kg gas bottles, and it can be pretty easy to run through the bottles regularly, which is more troublesome than topping up a jerry can with diesel (which is available almost anywhere).

Alternatives to a diesel heater

If you are looking for a way to stay warm at night, we wrote a post that covers how to keep warm when camping, but in summary, you have a few options.

Better clothes

Some good quality clothes that are designed to keep you warm make a big difference. Thin, tighter layer work better than thicker, loose layers. We usually take a set of thermals with us, which rarely get used, but they will keep you warm in pretty cold temperatures.

Hot water bottle

A lot of people boil a kettle and take a hot water bottle to bed. We’ve never tried this, and I think its easier to just wear appropriate clothing, but a lot of people swear by it.

Electric blanket

Electric blankets are one of the few heating devices that don’t use an excessive amount of power. You can either run a normal 240V electric blanket from your 12V batteries via an inverter, or you can actually purchase 12V electric blankets too.

If you leave them on all night they will use a decent chunk of power, but no where near the amount of a normal electric heater (which is almost impossible to run in the average off grid camping setup).

Using the stove to warm the van up

You’d be surprised how much warmth you can put into a van by just putting a kettle on the stove, and letting it boil. Obviously the water retains heat for a while, but I’ve seen it a number of times in my parents van, where they’ve warmed the entire van up considerably just by boiling a kettle.

Obviously this works less efficiently the larger the van, and the less insulation you have. Doing it in a pop top camper trailer would be almost pointless, as the heat escapes far too fast.

Do you really need a caravan diesel heater?

Again, only you can answer this question. People have been camping for years without diesel heaters, in climates that are far colder than what the majority of Australia gets to. That doesn’t mean its as enjoyable or as comfortable as it could be, but it has been done.

We purchased one because our soft floor was too uncomfortable for the kids to sleep in during the middle of winter, and they’d frequently wake up despite being dressed in a million layers.

Diesel heater outlet
Nothing beats warm air from a diesel heater!

The more insulation you have, the less likely you’ll need one; caravans do a much better job of staying warm than pop top hybrids, or camper trailers for example. 

We take our portable unit on camping trips where its going to be cold and we have the room, and we leave it at home on longer trips where there’s only going to be a couple of nights of colder weather.

Do you have a diesel heater? What do you think of it?

Smart Bull Bar Frost
If you are regularly camping in sub 10 degree temperatures, its a great option

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