October 24, 2020

Can You Install a Diesel/Gas Heater in an RV?

Webasto Diesel/Gas heater

YES. The Webasto gasoline heater I installed in our Class C motorhome could be the best heater I’ve used for winter RV camping. It’s a great alternative to propane heat. Still, I’m not aware of any other RV owners who have installed one.

In this article I’ll explain what lead me to install this type heater and why more RVers who enjoy boondocking should consider one.

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What’s wrong with propane heaters?

Heating with propane is certainly the most common heating option, but it has its drawbacks. When propane gas burns, it also creates water vapor as a byproduct. This may contribute to excess condensation inside your RV which could lead to mold or mildew build-up and possibly minor water damage.

Condensation on window
Condensation inside windows that can build up overnight in cold weather

The large propane furnace installed in your RV also draws power from your batteries to run the large fan inside. If used for extended periods (through the night for example), it may draw down your batteries. For this reason, many opt for portable propane heaters when dry-camping.

Portable propane heaters like the Mr. Heater Big Buddy Heater and Olympian Wave 3 Catalytic Heater consume little to no electricity and are generally effective in small spaces as long as you take the necessary precautions. While they are quite affordable and generally safe to use indoors, most RVers I know (including myself) still choose NOT to run a portable propane heater unattended or through the night.

Who uses diesel/gas heaters? 

Also referred to as parking heaters, diesel heaters are mostly used in the trucking industry. You’ll also find them installed on school busses or large agricultural equipment. 

Trucks at rest stop
Trucks parked at a rest-stop overnight

They’ve also become a popular heating solution for full-time van dwellers, cruising yachts, and European RVs (caravans). Use of these heaters hasn’t quite caught on with motorhome manufacturers here in the United States for reasons I’ll speculate on later. 

There are also gas/petrol versions of these heaters available for those of us who don’t burn diesel. This was a key feature that attracted my attention since I have a very large gas tank in my motorhome.

What are the benefits of a diesel or gas heater? 

The most significant difference between a gasoline heater and propane heaters is that it burns gasoline (or diesel fuel) instead of propane. 

This makes them best suited for RVs like motorhomes which already have a large gas or diesel fuel tank. You can also install an inexpensive external fuel tank to supply the heater.

A gas or diesel heater can be a worthwhile investment if you want to stay comfortably warm when off-the-grid. Here are a few key reasons why. 

They use very little fuel and electricity

You can leave it on all day and night. A high efficiency gas heater like the Webasto Air Top or Espar D2 consumes as little as one gallon of gas in a 24 hour period and draws between 0.8 – 2.4 amps of current at 12 volts DC when heating. 

They produce a dry comfortable heat

There’s no moisture generated which will decrease or eliminate condensation which can cause mold and mildew inside your RV. In fact running the heater will act like a dehumidifier and help dry out your RV. 

They are very safe to use

The fuel and exhaust components are completely sealed inside the heater. The fuel line, combustion intake and exhaust are located underneath the RV. So there’s absolutely no smell or venting needed.

Webasto Heater Connections
Exhaust, fuel line and combustion intake connected through the floor below the heater

You’ll feel comfortable leaving it running unattended or through the night.

Hidden and compact

This heater is small and can be permanently installed in a location on the floor where there is access to air-flow. There no need to store the heater and any additional components when not in use.

The combustion air intake, exhaust and fuel line run through a sealed hole in the floor. Heater controls are also very small and can be mounted anywhere for easy access. 

Evenly regulates and maintains temperature

By simply setting the desired temperature, the heater will adjust the output as needed to maintain an even temperature. This not only helps provide a comfortable environment, but also makes it run very efficiently. The output noticeably drops to a lower level as the target temperature is reached and maintained.

Webasto Heater Controls
Webasto Control Unit

It creates a very comfortable environment unlike the other heaters in our RV which will produce uncomfortable temperature swings. 

Some control units, like the one my Webasto kit came with, can be programmed for each time and day during the week. It’s a set-it-once and forget it kind of system. 

What are the drawbacks of installing a diesel or gas heater? 

For years we’ve used several propane heating solutions. We haven’t been fully content with any of them. The lack of good temperature regulation, condensation, and energy usage has always been an issue. 

The Webasto heater has been a great solution to all of these issues, but there are a few reasons why this may not be the best option for you. 

Not worth the investment if you’re on full-hookups most of the time

If you have electric hookups and don’t spend much time boondocking or dry camping, then using an electric heater will probably be your preference. Using one or two small space heaters is very effective for keeping the RV comfortably warm. 

You’ll need access to a diesel or gasoline fuel source

You may not have access to a diesel or gasoline fuel source. Even if you do, some vehicles don’t have an auxiliary fuel port on their gas tank. You’ll have to have one installed or install an auxiliary fuel tank. 

Webasto Heater Fuel Line
Incoming fuel line mounted under RV floor

Note: Having removed my generator, I was able to reuse the generator fuel line on my RV. This worked out very well to fuel the heater.

Can be an Expensive Solution

Finally, Webasto and Espar heaters can easily run over $1000 when installed. Many who own them have started with less expensive propane options first before deciding to upgrade to a diesel or gas heater. 

Having said that, there are now inexpensive Chinese-made diesel heater kits like these on Amazon for under $200. 

Why aren’t they used much in RVs?

I can only speculate on this and assume it’s because of one of these reasons.

First of all, most new RV owners aren’t going to be camping off-grid much. For those that do, a propane heater and generator will typically meet their needs for short periods.

Secondly, most RVs sold today are towables (i.e. travel trailers and fifth wheel RVs) that have one or more propane tanks and no gasoline or diesel tank. 

Lastly, diesel/gasoline heaters are not manufactured here in the United States and are difficult to find. Many custom van-build shops install them regularly though. 

Where can you buy them?

Webasto and Eberspacher are the two main manufacturers of diesel or gas/petrol heaters located in Germany. In fact, I’ve heard that their factories are very close to each other. Simply contact one of their dealers or order through an on-line retailer like Heatso.com

Most heater kits (including the inexpensive ones) are pretty complete and can be found here on Amazon.com.

Do they need to be professionally installed? 

Most van build shops can install these heaters for you. You could install it yourself if you have a good set of tools and basic electrical and mechanical DIY skills. Keep in mind that you may need to get your installation inspected by an authorized dealer to activate the warranty.

Here’s a list of diesel/gas heater kits and materials I’ve put together to get you started.

As always, do your research ahead of time and watch a few DIY installations on YouTube first to see if this is a project you want to take on yourself.

Conclusion

Heating and cooling your RV off-the-grid are two of the biggest challenges to staying comfortable on the road. Having a diesel or gas heater definitely can eliminate the heating challenge. It’s definitely worth considering if you do a lot of dry-camping in cooler climates and are not satisfied with your propane heater.

Most of those who’ve installed diesel or gasoline heaters will agree that it’s the best option available. 

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