Espar / Eberspacher Airtronic D4R Recreational 12v (4kW) Heater Kit

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The Espar D4R air heater offers the best fuel economy of any Espar diesel heater, and has the power to handle up to 70 feet / 21 meters of ducting thanks to its unique fan shape. It boasts an extended running life of up to 5,000 hours of operation, and can handle both high altitudes and low temperatures with no need for additional wiring. While offering heating output of up to  4kW / 13650 BTU, the Espar D4R Recreational heater is quiet thanks to its brushless fan and improved pump. With thermostatic function, timer and an advanced controller communication system, it is also very easy to operate.

Key features of the Espar D4R Recreational heater kit

  • The Espar D4R is an ideal RV heater, offering an heat output of up to 4kW / 13650 BTU and impressive fuel efficiency and cost effectiveness.
  • The unique fan on this air heater propels air further through the ducting system than other models. This means it can handle up to 70ft / 21m of ducting and multiple ducting outlets. 
  • Ducting outlets of 60mm, 75mm and 90mm can be used, and the number of outlets can be varied based on the complexity and specific needs of the ducting system.
  • If you have less complex ducting requirements, the Espar Airtronic D4L is a suitable alternative. It has the same functionality as the D4R, but supports a shorter ducting length and fewer outlets.
  • The Espar D4R can be run from an external fuel tank, and is the most fuel efficient diesel heater on the market, using just 0.51L of fuel for one hour’s operation at maximum heat output.
  • The Espar D4R Recreational heater kit is able to operate in high altitudes when equipped with the EasyStart Pro controller, which we highly recommend. This controller offers automatic altitude adjustment, and with it this Espar diesel heater works at up to 9,900 feet / 3,000 m. 
  • No additional wiring or installation is required for high altitude operation.
  • This diesel heater for RVs and boats can operate in temperatures as low as -46 C / - 50 F.
  • Controlling the Espar D4R is easy when using the EasyStart Pro, and includes a timer and thermostatic functionality thanks to its integrated temperature sensor.
  • The Espar D4R Recreational heater kit is quieter than previous models because of its new stepless blower system (which reduces clicking noise) and its brushless fan.
  • Like most Espar heaters, the D4R features plug and play installation, which means you can install the system yourself with fewer tools required and no need for cable crimping.
  • Fuel system installation has also been simplified, with the same line used for the entire installation.
  • The Espar D4R Recreational heater kit uses all 3 protocol technologies in the Espar product range - CAN, LIN and S+. As a result, you can use earlier generation controllers with the D4R.
  • This is a reliable diesel heater for RVs and boats from a reputable German manufacturer. And if there are any issues, the Espar D4R’s new controller communication systems gives improved accuracy with on screen fault diagnostics.
  • Thanks to its brushless fan, this Espar diesel heater has an extended operating life of up to 5,000 hours (compared to 3,000 hours in earlier models). 
  • For specific RV, van or marine applications, custom kits are available. Contact the Heatso team for a custom kit. We can even calculate ducting rates, suggest outlet options and plan the layout for you (for marine applications).

User benefits of the Espar D4R Recreational heater kit

This Espar diesel heater is an excellent choice for RVs, and for trucks, lorries and semi-trucks which need to heat more cabins. It offers the best fuel efficiency of any Espar diesel heater on the market, requiring just 0.5L of fuel for one hour’s heating at maximum power. 

It also offers excellent versatility in terms of installation. With ducting possible up to 70ft / 21m, it is well suited to a wide range of vehicle types and applications. It is two times as powerful as the Espar D2L unit, and smaller than the Espar D5, which means it can offer powerful heating where space is limited (although please note it can be awkward to install under the passenger seat in vans).

Offering high altitude performance when paired with the EasyStart Pro controller, plus reliable heating even in very cold conditions, this is a robust diesel heater that’s engineered to last.

Who the Espar D4R Recreational heater kit is suitable for

This diesel heater is suitable for RVs and boats, and  ideal for trucks, semi-trucks and lorries thanks to its longer ducting possibilities. It is suitable for use in:

  • Trucks / Semi-trucks / Lorries
  • Vans
  • RVs / Campervans / motorhomes
  • Caravans
  • Horse Boxes
  • Mobile Workshops
  • Boats (requires marine kit)

Heatso’s engineers are here to help

The Espar D4R 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 onhand 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.

Technical specifications:



Diesel – EN 590

Heat Flow Control





Heat Flow










Fuel Consumption

l / h





gal/ h




Average Power consumption





Average Power Consumption while Starting



Rate Voltage


12 volt

Dimensions LxWxH


371 x 140 x 150

Kit Contents:

  • Eberspacher Airtronic D4R 12v Heater
  • Fuel pump (12v)
  • Fuel hose
  • Exhaust Silencer
  • Electrical harnesses
  • Stainless steel exhaust pipe
  • Combustion intake pipe 
  • Flexible ducting - 1 meter
  • Inlet / Outlet grills
  • Air outlet (90mm)
  • Screws, clips and plastic straps required for installation
  • Installation manual
  • Warranty documentation 

Eberspacher / Espar Part Number:

  • 25.2746.05.0000/  25.2746.05.00.00/ 252746050000(Heater)
  • 25 2720 80 0000 / 25 2720 80 00 00 / 252720800000 (Installation kit)

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

If you want to use this heater in a boat, you will need a marine installation kit. You can add it to your order at the bottom of this page. Please click here to see what is included in the marine installation kit.


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

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.

2 Reviews Hide Reviews Show Reviews

  • 5

    Posted by D WELLS on 10th Jun 2020

    I upgraded my Airtronic 4 with this. Bit annoyed that I had to change the whole electrical wiring part, but worth ti at the end.

  • 5
    One of best customer service

    Posted by Chester on 11th May 2020

    I love this heater! At very first I was not entirely sure which heater to get and that is where great folk at Heatso came in help. After a lot of chatting (I was very nit-picking, tbh) they recommended this model and thoroughly explained why. So, I bought it.. Got it super quick! I think it took like 3 to be delivered. Installed it and now I am enjoying amazing comfort this heater provides.
    Highly recommended! If in any doubt, just ask Heatso folk. They really do care about their customers and helps you through everything.