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Chinese Diesel Heater vs Webasto vs Espar D2

Eberspacher Espar Airtronic S2 D2 L 12V 2.2kW 7500BTU with Webasto Air Top 2000 STC heater Diesel single outlet 12v Diesel Air Heater Forced Air Parking Heater 5KW 12V +
Eberspacher Airtronic Espar S2 D2LWebasto Air Top 2000 STCChinese Diesel Heater

Tired of cold nights in the campervan? You need a diesel heater. They provide tons of heat, they connect directly to your fuel tank, and they can be used while you’re driving or when you’re parked somewhere for the night. We reviewed and compared the three best diesel heaters available: the Eberspacher Airtronic Espar S2 D2L, the Webasto Air Top 2000 STC, and the best 5kw Chinese diesel heater on the market. We considered price, noise, efficiency, and everything in between.


The Espar S2 D2L is the new and improved version of the Espar D2 parking heater. It features a new brushless motor, it’s quieter and lasts longer, and it has an integrated altitude sensor that automatically adjusts the fuel delivery rate up to an altitude of 10,000 ft.


For over 150 years, Eberspacher has built a reputation as a company that produces reliable, quality products. The Espar S2 D2L is no exception.

It’s constructed of precision parts that fit together and seal perfectly so you won’t have to make any surprise visits to the hardware store during installation. It’s also rated for 5,000 hours of use, improving upon the D2’s 3,000 hour service life.


The EasyStart Pro controller is new with the Espar S2 D2L heater and it’s Eberspacher’s best design yet. The amber LCD screen is easy to read and all settings and functions are controlled with a single dial for simple operation.

It displays the status of all heater functions as well as the current interior temperature. It includes a timer option, a sleep mode to save battery life, and it’s compatible with the heater’s new altitude sensor. A self adhesive foam underlay and mounting bracket allows you to choose your method of installation.


The Espar S2 D2L is also the quietest diesel heater on the market. With the new brushless motor design and near-silent air blower, you won’t have to worry about it waking you up in the middle of the night. It also has a new fuel metering pump that eliminates the clicking sound the D2 used to make.

As if that weren’t enough, the upgraded exhaust system works in tandem with the muffler to ensure that you’re not the noisy neighbor at the campground. Well, at least not because of your heater.


Since it’s a 2.2kw air heater, it produces 500 more BTUs than the 2kw Webasto Air Top 2000 STC (700 more BTUs if the Webasto has been adjusted for high altitude). While it’s not a huge difference in heat output, it’s significant enough to mention.

With an air flow rate of 62 cfm (cubic feet per minute), this parking heater is great for heating a retrofit camper van, boat cabin, or semi truck cab. It’s a reliable, powerful heater that will keep you warm in the winter.

High Altitude

Unlike the Espar D2 that required you to install an expensive high altitude kit, the S2 D2L has an integrated altitude sensor that adjusts automatically. The sensor detects the atmospheric pressure and sends the data to the controller where it adjusts the fuel delivery rate to the combustion chamber. No user input or installation is required whatsoever.

Service life of 5,000 hours Expensive
Quieter brushless motor
EasyStart Pro LCD controller with stepless heating
Built-in altitude sensor with automatic adjustment
Quieter fuel metering pump and exhaust emissions


Webasto is a German automotive parts company that has been making engine-independent diesel heaters since the 1930s. Their new and improved Air Top 2000 STC model is their best heater yet – it’s high quality, energy efficient, and perfect for heating a parked vehicle.


At its highest setting, the Webasto diesel heater uses just 0.24 liters of fuel per hour and 29 watts of electricity, making it the most energy efficient diesel heater available. Its low fuel consumption and fewer emissions are cleaner and better for the environment which has earned it a CARB approval and EPA SmartWay verification.

Best of all, it’s capable of running for 22 hours on a single gallon of fuel, so it ends up paying for itself in just 40 nights.


Like all diesel heaters, The Air Top 2000 STC makes some noise during the combustion process when the heater initially turns on. It quiets down after a few minutes and stays quiet while it’s in the heating phase.

If you’re using this bunk heater in a small space like a retrofitted van conversion, it could warm up the van in as little as ten minutes. The heater would then shut off until it got cold enough for the combustion process to fire up again. If you’re a light sleeper, we suggest cracking a window or turning on a small vent fan. It’s not the most energy efficient way of doing things, but it delays the noisy startup process.

If you occasionally stay in RV parks or campgrounds then you may want to consider picking up a muffler. While you may not be able to hear your heater’s exhaust from inside your vehicle, those around you certainly can. A muffler greatly reduces exhaust noise and your neighbors will thank you.


With a 7,000 BTU (2kw) rating and an air flow rate of 55 cfm, the Webasto bunk heater is big enough to heat semi truck cabs, boat cabins, retrofit vans, or small RVs.

How long your vehicle takes to fully heat will depend on the temperature outside as well as your vehicle’s insulation. You can heat your dwelling in cool weather relatively quickly, but colder climates require much longer heating times. For reference, a high roof cargo van takes about two hours to heat from 10ºF to 60ºF.

High Altitude

While the Webasto Air Top 2000 STC is not compatible with high altitude kits, it can be manually adjusted with the included rheostat. It’s a detailed process, but once the oxygen/fuel mixture has been adjusted for high altitude there’s no need to change it back when you get down to sea level.

With the new adjustment, the combustion process will use slightly less fuel and you’ll lose out on up to 200 BTUs (around 3%), but you’ll have the peace of mind knowing that your heater will work no matter what heights you travel to.

Rheostat adjustment:

  1. Locate the brown/green 2-wire pigtail at the bottom of the heater.
  2. Connect the brown wire to ground.
  3. Turn the heater rheostat to 12:00 (1:00 if at 10,000 ft or higher).
  4. After a few seconds, the LED on the rheostat will start to flash.
  5. Turn the rheostat to 9:00 (8:00 if at 10,000 ft or higher).
  6. Keep the heater running for 3 minutes with rheostat still at 9:00.
  7. While still running, remove the brown wire from ground.

Other Models

Small and compact for installing in tight spaces Not compatible with high altitude kit
Most energy efficient heater available LCD SmarTemp Control 2.0 sold separately
Uses as little as one gallon of fuel per 22 hours
High quality parts from a trustworthy company
Integrated control unit with room temperature sensor


Chinese diesel heaters are ‘private label’ products. This means that a manufacturer in China produces an unbranded, generic product and then sells it to various companies who then put their own brand name on it.

For the sake of comparison, we reviewed the 5kw Chinese diesel heater with the blue controller and red remote because it’s one of the few models that has a high altitude sensor. Unfortunately, we couldn’t find a 2kw heater that had one.

If you plan on staying below 5,000 ft then we recommend the HappyBuy 3kw air heater, as the 5kw heater is too powerful for most uses and is bulky and difficult to install in tight spaces.


The most attractive thing about Chinese diesel heaters is the price. At around one tenth of the cost, it’s a great way to get cheap heat on a budget. You could even buy a second one as a backup and still only be paying a quarter of what you would be for an Espar or Webasto.


Unfortunately, this is where things fall apart. Unlike the Webasto or Espar heaters, quality is not a priority when these are being mass produced. Either the parts don’t fit correctly or they are so cheaply made that you’ll need to replace them. Here are a few issues that customers had:

  • Fuse blows every time it goes through the startup process
  • Fan stopped working, causing overheating and smoking
  • No installation instructions
  • LCD display either doesn’t work or the buttons are finicky
  • Cheap plastic fuel line causes leaks
  • Sets off carbon monoxide alarms
  • Mufflers are hollow and don’t do anything

It’s not guaranteed that you’ll experience any of these problems but it’s worth taking into consideration.


Fortunately, these heaters produce plenty of heat. The 5kw heater is over 17,000 BTUs and can heat not just smaller vehicles, but larger vehicles like RVs and small buses. With such a large heat output, it takes very little time to heat a space, even in freezing temperatures.


Since Chinese heaters use lower quality parts, they’re noticeably louder than Webasto or Espar heaters, especially the 5kw models. The three main sources of noise comes from the motor, the fuel pump, and the exhaust.

  • Motor. While many people think the fan causes most of the noise (in some instances, it does), it’s been proven that a majority of the heater’s noise comes from the motor itself. The video below is of a 2kw model, so you can imagine how much louder a 5kw heater would be.

  • Fuel Pump. The fuel dosing pump that delivers fuel to the heater makes a constant ticking sound that sounds like a clock. It varies its rate of ticking depending on how hard the heater is working.

  • Exhaust. The first thing you’ll want to do is replace the muffler on the exhaust system, especially if you’re going to be parked around other people. Also, be sure to keep the exhaust hose as short as possible with minimal bending to reduce noise.

LED controller and remote key fob Low quality parts don’t fit correctly and may leak fuel
Cheap and affordable Prone to failure
Can hook up to vehicle tank or external tank (included) Very loud
Potential safety hazard

How To Choose The Best Diesel Heater – Buying Guide

diesel pump

What is a diesel heater?

A diesel heater is a small heating apparatus that runs on diesel fuel and is typically installed in semi trucks, RVs and retrofitted vans. They connect to the main fuel tank and provide fast and efficient heat to parked vehicles.

How it works

Outside air is sucked into the heater’s combustion chamber, along with a small amount of diesel fuel. This mixture of fuel and air combust and produce heat, heating up the metal heat exchanger.

The waste from the combustion process exits through the exhaust pipe. The air inside your vehicle gets sucked into the heater by a small fan, which is then warmed up by the hot metal heat exchanger. The warm air is then blown into the cabin by a larger fan, effectively heating your vehicle.

Why do I need one?

Forced air diesel heaters are essential when traveling and can be used in a number of different vehicles and settings:

  • Retrofitted Vans and Campervans. Perhaps the most popular use for diesel heaters is for converting a van into a sleeper van for traveling. Due to the low air pressure at high altitudes, the temperature is often colder, especially at night. A diesel heater provides you with a warm night’s sleep no matter where you’re parked.
  • RVs and Motorhomes. Much like campervans, you’ll want to be prepared no matter where you travel to. RV parks provide power hookups but if you’re planning on boondocking during the colder months then you’ll want to install a diesel heater to stay warm.
  • Semi Trucks. Often called bunk heaters, diesel heaters can be installed in semi trucks to keep the sleeper berth area warm without idling the truck. This saves fuel and keeps the driver warm.
  • Boats. Whether you have a sailboat or a small yacht, it’s important to stay warm when you’re cruising. With a diesel marine heater, you’ll never have to worry about catching an early cold front or leaving late from the North.
  • Sheds and Garages. Maybe you enjoy a hobby out in the shed or you like to work on your car in the garage, you don’t have to freeze your butt off while you do it. Just be sure to use proper ventilation and you’ll be nice and toasty.

semi truck on open road

High Altitude

Not only are higher altitudes colder due to lower air pressure, but diesel heaters are more prone to failure without the right adjustments. The combustion chamber in the heater requires a precise mix of oxygen and fuel.

At high altitudes, the low air pressure causes a reduction in oxygen which in turn causes an excess of fuel in the combustion chamber. This unbalanced mix of fuel and oxygen can cause the heater to fail.

There are several ways to ensure that your diesel heater can be used at high altitudes:

  • Manual adjustment. Some diesel heaters, like the Webasto Air Top 2000 STC, can be manually adjusted for high altitudes without the need to purchase a separate kit. After this one-time adjustment, the heater can be used at any altitude. You’ll lose around 3% heating capacity at sea level but it’s a small price to pay for being able to travel anywhere with a working heater.
  • Separate fuel line. The Espar D2 (old model) has the option of installing a second fuel pump alongside the original one. The second fuel pump would be set to deliver a lower rate of fuel so it could work at high altitudes. Both fuel pumps would be connected to an electrical switch that would allow you to switch between fuel pumps depending on your altitude.
  • Automatic sensor. By far the most convenient solution is to have a sensor that detects atmospheric pressure. It sends that information to the controller which automatically adjusts the fuel delivery rate based on altitude. It’s a completely automated and hands-free process.


Every heater installation will be different. It’s best to follow the instructions that came with your particular heater. Below is a good video that shows a typical installation.


One of the biggest safety concerns is carbon monoxide poisoning. They call it the silent killer – and for good reason. If not ventilated properly, or if there’s a defect in the unit, carbon monoxide can build up inside the vehicle and may cause death. We highly recommend installing a couple of CO detectors in your vehicle.

The Webasto and Espar heaters are EPA verified and are very high quality, but accidents and improper installation still happens. The real risk is from the cheap Chinese heaters. They don’t follow the same regulations and are more prone to defects.

Regardless of which heater you decide to go with, always have a working carbon monoxide detector in your vehicle.

Frequently Asked Questions (FAQ)

camper van parked by pine trees

How do you adjust the temperature?

Depending on the heater you have, you can either adjust the temperature with an LCD controller or a rheostat. Higher end heaters have stepless heating and programmable timers.

Do diesel heaters smell?

If installed correctly, diesel heaters do not smell while you’re inside the vehicle. The exhaust system is located outside the vehicle and may have a faint smell, especially when it’s fired up for the first time and the combustion process starts.

Can I use the heater while I’m driving?

The great thing about diesel heaters is that they can be operated while the vehicle is in motion as well as when it’s parked.

How do I power the heater?

A diesel heater should be powered by a separate battery. Otherwise, there is a risk of draining the vehicle’s battery and getting stranded.

Comparison Table

Eberspacher Airtronic Espar D2 D2LWebasto Air Top 2000 STCChinese Diesel Heater
Product Eberspacher Espar Airtronic S2 D2 L 12V 2.2kW 7500BTU with Webasto Air Top 2000 STC heater Diesel single outlet 12v Diesel Air Heater Forced Air Parking Heater 5KW 12V +
Price$ $ $ $ $$ $ $ $ $$ $
Quality & Reliability969568
Temperature ControlYesYesYes
Vehicle Tank HookupYesYesYes
Portable Tank IncludedNoNoYes
Mounting Hardware IncludedYesYesYes
CARB Approved & EPA VerifiedYesYesNo
Heating Capacity7,500 BTU/h (2.2 kw)7,000 BTU/h (2 kw)17,060 BTU/h (5 kw)
Fuel TypeDieselDieselDiesel
Fuel Consumption0.03 – 0.07 gal/h (0.1 – 0.28 l/h)0.03 – 0.06 gal/h (0.12 – 0.24 l/h)0.03 – 0.13 gal/h (0.11 – 0.51 l/h)
Rated Voltage12 V12 V12 V
Operating Voltage Range10.5 – 16 V10.5 – 16 V10.5 – 16 V
Power Consumption0.42 – 2.83 Amps (5 – 34 Watts)1.25 – 2.45 Amps (14 – 29 Watts)N/A
Air Flow62 cfm (105 m³/h)55 cfm (93 m³/h)105 cfm (178 m³/h)
Diameter Air Outlet2.36 in (60 mm)2.36 in (60 mm)N/A
Diameter Exhaust0.94 (24 mm)0.87 in (22 mm)N/A
(L x W x H)
12.2 x 4.53 x 4.8 in (310 x 115 x 122 mm)12.25 x 4.78 x 4.85 in (311 x 120 x 121 mm)16.5 x 16.1 x 4.5 in (420 x 410 x 155 mm)
Weight5.95 lbs (2.7 kg)5.73 lbs (2.6 kg)N/A
Warranty2 Year, / 2,000 Hour Limited Warranty2 Year / 2,000 Hour Limited WarrantyNo
Manufacturing LocationEuropeEuropeChina


We hope that this guide has provided you with all the information you need to make an informed decision. As you can see, each heater has its strengths and weaknesses.

In our opinion, the Espar S2 D2L is the best of the best. It’s the most expensive but it has an integrated high altitude sensor, it comes with an intuitive LCD remote, and it’s the quietest.

The Webasto Air Top 2000 STC makes traveling to high altitudes somewhat difficult, but it’s the most energy efficient heater and is capable of running for 22 hours on a single gallon of diesel.

And there’s no arguing that a Chinese diesel heater is the best bang for your buck, but it may require some tinkering and a trip or two to the hardware store.

Whichever diesel heater you choose, you’ll look back and wonder how you ever went so long without one.