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Espar / Eberspacher Airtronic B4L M2 (Petrol) 12v (4kW) Heater Kit - NEW ECU's

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  • Espar / Eberspacher EasyStart Pro Timer 221000352200

2019 version Espar / Eberspacher Airtronic B4L M2 12v Air Heater With Installation Kit

The Espar B4L gasoline heater with installation kit 

This powerful 12V van heater offers versatility and optimized heating control, even in extreme conditions. It is suitable for use at high altitudes (up to 9,900 feet / 3 kilometres) with no need for an additional high altitude kit. It can operate in temperatures as low as -46°C / -50°F. Installation has been made as simple as possible, while the B4L has been engineered to offer comfort and performance with noise levels minimized. Compatible with a wide range of vehicles, and especially well-suited to vans, this is one of the most popular petrol / gasoline heaters on the market. Please note this heater is not suitable for use in marine applications.

Key features of the Espar B4L gasoline heater

  • The Espar Airtronic M2 B4L is the most powerful petrol / gasoline heater available, offering 4kW / 13650 BTU maximum heat output. This power, combined with the B4L’s advanced features and engineering, makes it one of the most popular petrol / gasoline heaters on the market. 

  • The Espar B4L is engineered to operate in extreme conditions and high altitudes. It can operate in temperatures as low as -46°C / - 50°F and at altitudes of up to 9,900 feet. This is enabled thanks to its integrated altitude sensor, and unlike earlier models there is no additional wiring or installation required for high altitude operation.

  • Controlling the heater is simple because it has an integrated temperature sensor and EasyStart Pro controller. The Espar B4L’s stepless blower system enables optimized heating control and maximizes performance efficiency. 

  • The stepless blower system also ensures quieter performance compared to previous models, while the improved fuel pump piston reduces clicking noise. The Espar B4L also sports a brushless fan which helps to further reduce noise.

  • The Espar B4L is highly versatile when it comes to installation. Its adaptable ducting system, which can go up to 15 meters / 49ft in length, features outlets of either 60mm, 75mm or 90mm. Ducting outlets are closeable and can have different degree grilles and outlet types, plus the number of outlets can be varied based on the complexity of the ducting system. 

  • The Espar B4L is easier to install than previous models. It features plug and play  installation which requires fewer tools and no cable crimping, enabling DIY installation. 

  • The heater’s fuel system plugs directly into your vehicle’s fuel system or tank with a standpipe (Optional) or via an auxiliary tap (if your vehicle manufacturer offers one). Installation of the fuel system has been simplified for this model, with the same line used for the whole installation. 

  • The Espar B4L is compatible with all 3 communication protocol technologies used by Espar - CAN, LIN and S+. This means you can use your earlier generation controller with the Espar B4L

  • Custom installation kits can be arranged based on requirements of your vehicle (get in touch with the Heatso team to discuss your specific needs).

  • The brushless fan ensures the Espar B4L has a long operating life, increasing service time from 3k hours (on previous models) up to 5k hours. And if there are any issues, the its new controller communication system allows more accurate on-screen fault diagnostics.

User benefits of the Espar B4L gasoline heater kit

There are many reasons why the 12V gasoline heater is so popular as a van heater. Its powerful heat output (4kW / 13650 BTU max heat output) is a clear advantage, as is the ability to use it in extreme conditions, including at high altitudes and in low temperatures. This heater also offers strong fuel efficiency, and is a cost-effective option especially for long-term usage.

If you are looking for a gasoline heater you can install yourself, the B4L is a smart option. It’s compatible with various petrol / gasoline vehicles, and is especially popular with Ford Transit and RAM Promaster owners. With plug and play installation, a wide range of ducting options, and simplified fuel system installation, it is engineered to be easy to install.

You also have plenty of options as to where you install the fuel metering pump and heater within your vehicle. Reduction of the pump’s clicking noise means it can be installed in sleeping areas with less disturbance, and the B4L has the same base dimensions as the Airtronic D2, D4 and B4, making it a suitable replacement.

Who the Espar B4L gasoline heater kit is suitable for

This Espar gasoline heater is suitable for a wide range of vehicles and applications, and is ideal for heating:

  • Trucks
  • Vans (especially the Ford Promaster and Transit)
  • Campervans
  • Caravans
  • Horse Boxes
  • Mobile Workshops

Please note petrol / gasoline heaters can only be used in road vehicles, and are not safe for use in marine applications.

Heatso’s engineers are here to help

The Espar B4L is an excellent heating option for your vehicle. But if you have any questions about it, or would like to hear about other options, our customer service is on-hand to help. And when you do find the ideal solution to meet your needs, our engineers are available to talk you through the whole installation process, step by step.

Espar Airtronic AS3 B2L 2KW petrol heating

If you're looking for reliable air heating for your petrol van, you may not need 4KW of heating power. Check out the cutting-edge 2KW Airtronic B2L petrol air heater and find out if it's the right heater for you!

Technical data:



Gasoline / Petrol – DIN EN 228

 Heat Flow Control





 Heat Flow










 Fuel Consumption

l / h





gal/ h




 Average Power consumption





 Average Power Consumption while Starting



 Rate Voltage


12 volt or 24volt

 Dimensions LxWxH



Eberspacher / Espar Part Number:

  • 20.1987.05.0000 / 201987050000 (Heater)
  • 20 1987 05 0000 / 20 1987 05 00 00
  • 25.2720.80.0000 252720800000  (Installation kit)
  • 25 2720 80 0000 25 2720 80 00 00

Kit Contents:

  • Espar Airtronic B4L 12v Heater
  • Fuel pump (12v)
  • Fuel hose
  • Exhaust Silencer / muffler
  • Electrical harnesses
  • Stainless steel exhaust pipe
  • Combustion intake pipe 
  • Flexible ducting 
  • Inlet / Outlet grills
  • Air outlet
  • Screws, clips and plastic straps required for installation
  • Installation manual
  • Warranty documentation 

Shipping Times:

  • United States - 1 Working Day
  • United Kingdom - 1 Working Day
  • Western Europe - 2-3 Working Days
  • Eastern Europe - 3-5 Working Days
  • Scandinavian Countries - 2-3 Working Days
  • Australia / New Zealand - 2-3 Working Days
  • Rest of World - 2-4 Working Days


Installation, servicing and maintenance must be done in accordance with manufacturer’s guidelines. Failure to follow these guidelines will result in voiding your warranty. 

We provide free technical and installation support via email or phone to all of our customers who purchase a heater, heater kit or other products from Heatso. We take pride in our customer service and want to ensure that your heater system is properly installed. As a result, if you have any difficulties, please do not hesitate to contact us at [email protected].

If you require removing and/or refitting your item, please visit a local professional or authorised specialist, if you can not find one you can contact us and we will try to recommend a local partner to assist with the task. The cost of removing and/or refitting this item is not covered by the warranty.

Standard/Premium Warranty Terms for Espar/Eberspacher or Webasto Heaters & Heater kits

2 Years + optional 1 year extended Warranty available

If the item has failed within warrantable conditions:

  1. Please fill out the contact form on the “Contact us” page.
  2. A representative will contact you within 24 business hours to confirm the details and assist you further.
  3. If the product needs to be inspected by our service engineer, we will provide shipping labels for you to print and attach before handing over to our courier for collection.
  4. The shipping label will contain instructions for arranging pickup at your location or drop off at a nearby FedEx location. Follow these instructions to pass the package to FedEx.
    1. *The Label must be attached to the packages before leaving the package with FedEx.
    2. *You can also choose to drop off the item at a FedEx post office instead of requesting a courier collection.
    3. *If after inspection it appears that the item is not warrantable and the malfunction is caused by a non-warrantable condition, we will kindly ask you to cover shipping expenses at a discounted flat rate.
  5. On average, diagnostics of heaters and their parts takes 3 to 4 working days from the moment the item has reached our warehouse.
    1. *The diagnostics report is provided by a manufacturer approved authorised service centre.
  6. If during diagnostics it was concluded that the fault falls under non-warrantable conditions, our customer support will reach out to you and provide you with an estimated repair cost.
    1. *Please note that we strive to provide the lowest possible repair prices.
  7. Under normal circumstances it can take 3-7 working days after diagnostics to repair most minor malfunctions.
    1. *Please note that each case is unique and your repairs may take longer depending on the fault.


*Please note that all deadlines above are approximate and everything depends on the specific details of each case.

**If your item has been installed by a third party, please save all the documentation.This documentation can help find and fix the fault faster.

6 Reviews Hide Reviews Show Reviews

  • 5

    Posted by Todd Ritchie on 17th Nov 2020

    On of the better purchases I have made for my Vanagon Westfalia! Toasty warm on cold nights. Highly recommended.

  • 5
    Works great in Ford Transit

    Posted by Nate on 21st Oct 2020

    I installed the Airtronic B4L two weeks ago and we have been on two overnight trips and it is perfect! I turn it on or set it to run all night and it heats up fast and it is quiet. We didn't notice any loud clicking sounds from the pump and the air blower is smooth and creates a nice white noise for sleeping. Plenty of BTU power to heat the van.

  • 5
    Great heater, even at 9,000 ft!

    Posted by Drew on 24th Feb 2020

    This heater works great for a van like a Promaster. It has now kept us warm for many nights running for 8 hours or more at a time, even at elevations of 9,000 ft. I give the heater five stars.

    However, it did take some time for to get me the correct heater. They accidentally shipped the diesel model of this heater. After taking weeks to clear customs, I had to send the heater back so they could ship the correct one. Quite the problem when shipping international and resulted in about 6 weeks or more from when I placed the order, until I received the correct unit. I also swapped out mounting plates for the flat mounting plate, but have not received a refund for that difference.

  • 5
    Highly recommend

    Posted by Remington on 21st Dec 2019

    The install wasn't too difficult, the installation kit came with everything I needed (and more) and the heater is working well so far! The instructions aren't the best but if you stare at it long enough you'll figure it out haha..

  • 3

    Posted by Danny on 17th Dec 2019

    This is the latest espar 14k btu petrol heater and the manufacturer had huge problems with the control units so I suggest you get a unit from later batches. I ordered this kit as soon as it was introduced so it had that shitty ECU - took some time to sort out but heatso were really helpful and I now have the new type ECU which seems to be working fine. Overall it is a good heater just make sure you get the latest model with latest ECU version!!! The merchant is fine - very friendly and helpful guys.

  • 5
    Espar Airtronic B4L [email protected]

    Posted by LMS on 13th Oct 2019

    Excellent heater for my high roof Transit!