The Real Talk Guide to Truck Camper Air Heaters (and Why “Wet Heat” Is Mostly a Myth)

If you’ve spent any time in overlanding forums, you’ve probably seen people get way too passionate about air heaters. Diesel vs. propane. Dry vs. wet heat. And then someone inevitably jumps in yelling about moisture, fuel contamination, or how you’re “doing it wrong.”

So let’s clear the air (pun intended). Whether you’re building a mobile ski lodge on wheels or chasing desert sunsets, the heater you choose makes or breaks your cold-weather setup. Below, we’re breaking down every major truck camper air heater type, how each fuel source works, and which one is actually worth your time.

What Is the Difference Between Wet and Dry Heat in a Camper?

This is one of those topics that refuses to die online, even though it’s been outdated for decades. The short version: modern sealed and vented combustion heaters don’t make your air “wet.”

Older propane heaters did. Back then, the combustion process wasn’t sealed off from the living space. When propane (C₃H₈) burns, it combines with oxygen and produces carbon dioxide and water vapor. If that water vapor has nowhere to go, it condenses on cold surfaces and makes everything feel damp.

Modern systems like Propex and Truma isolate combustion from cabin air completely. The heater pulls in outside air for combustion, vents the exhaust (including water vapor) outside, and transfers heat through a metal exchanger. The warm air inside your camper never mixes with those exhaust gases.

So if someone online tells you propane heaters create “wet heat,” tell them they’re about 30 years late to the conversation.

How to Choose the Right Heater for Your Truck Camper

Now that we’ve settled that, let’s talk about how to choose the right air heater for your truck camper. Your ideal setup depends on how you camp, what fuels you already carry, and where you’re going.

Here are a few things to keep in mind:

• Fuel convenience: If you already use propane for cooking, sticking with a propane heater makes life simpler.

• Vehicle integration: Diesel or gas heaters can pull fuel straight from your truck’s tank, but that can be expensive to install, risky if not done correctly, and might void your vehicle warranty.

• Fuel availability: Diesel is easy to find almost anywhere, but in some regions, fuel quality can be questionable. Propane is common in North America but harder to source internationally.

• Elevation and cold weather: Some heater types struggle at altitude or in extreme cold. While diesel and propane generally perform great in both of these categories, diesel tends to be our suggestion for extreme cold (with appropriate fuel additive) and propane is our suggestion for extreme altitude, as it will require less maintence.

• Recirculating vs. non-recirculating: Recirculating heaters reuse interior air for faster warm-up times. Non-recirculating units pull in fresh air each cycle.

• Heater sizing: A good rule of thumb is about 9.3 BTUs per square foot of camper space.
  

The Main Types of Truck Camper Air Heaters

There are five main types of air heaters used in truck campers: diesel, propane, gasoline, electric, and wood/pellet. Each has its own strengths and weaknesses depending on how and where you travel.

Diesel Air Heaters

Example brands: Webasto, Espar

Pros:

• Energy-dense fuel for long run times

• Dry heat and strong cold-weather performance

• Diesel is stable and safe to store

Cons:

• Requires its own tank if you have a gas vehicle

• Needs periodic maintenance; fuel treatment in cold temps

• Cheap suitcase-style units can be unreliable

Our take:
Diesel air heaters are the go-to for serious cold-weather truck campers and expedition rigs. They sip fuel and burn efficiently (if you buy a quality brand). They will require additional care at altitude but can be easily achieved through proper use. Just know that they’re designed to run best at medium to high output. Running them at low power for too long can cause carbon buildup, so choose the smallest size that meets your needs.

Propane Air Heaters

Example brands: Propex, Truma

Pros:

• Reliable, low-maintenance, and clean-burning

• Fuel doubles for cooking and campfire pits

• Maintains steady temperature control for long periods

Cons:

• Old catalytic heaters do create moisture

• Propane can be harder to source in remote areas

• Regulators and lines can freeze below 10°F

Our take:
If you’re camping in North America, propane heaters are the best all-around choice for most truck campers due to their lack of maintenance. Systems like the Propex HS2000 or Truma VarioHeat are compact, efficient, and safe. Just make sure your propane system is installed correctly, and you’ll enjoy quiet, reliable heat for years.

Gasoline Air Heaters

Example brands: Espar, Webasto

Pros:

• Uses the same fuel as your vehicle

• Useful for international travelers with gas-powered rigs

Cons:

• Less reliable over time

• Poor performance at high elevation

• Gasoline is more flammable than diesel or propane

Our take:
We rarely recommend gas heaters unless you’re traveling internationally with a gas vehicle and can’t easily find propane or diesel. They work, but reliability and safety can both be concerns.

Electric Air Heaters

Pros:

• No combustion or exhaust gases

• Quiet and maintenance-free

Cons:

• Requires a large power system

• Can quickly drain your batteries

Our take:
Electric heaters are best as supplemental heat for small, well-insulated campers with serious power systems. They’re great for shore power setups or quick use, but not for sustained off-grid heating.

Wood and Pellet Stoves

Example brands: Dickinson, Cubic Mini

Pros:

• Natural, renewable fuel source

• Creates a cozy, cabin-like atmosphere

Cons:

• Hard to control temperature

• Can produce smoke and sparks inside

• May void insurance coverage or violate campground rules

Our take:
Wood stoves look amazing and feel nostalgic, but they’re better for aesthetic builds than practical heating. They’re fun, but also smoky, unpredictable, and sometimes unsafe in small spaces.

Comparing Them All Side-by-Side