What is a diesel air heater?

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In very simple terms it is a vehicle warm air heater powered by diesel as opposed to LPG or electricity.

It is a fast and effective way of introducing heat in to your vehicle.

“But we already have LPG heating“.  Fantastic, you already know the level of comfort that warm air heating provides. Adding a diesel air heater to your system acts as a backup in the event of issues with either your existing system running out of LPG, overnight temperature drops causing your Truma to dump, plus a lot more.

HEATER SIZES - What is best?

2kw - Small to medium sized vehicle / boat

4kw - Medium / large sized vehicle - best all round performer both small, med and large vehicle / boat.

6kw - reserved for the larger vehicle/ boat, normally with multiple outlets required.

The advantages are numerous over the alternatives, but one of the main ones is cost of running. Our 4kw heater will burn less than 100ml/ 150ml of fuel overnight at a reasonable set temperature.

  • Safe
  • No smell
  • Quiet
  • Reliable
  • Warm - A 4kw unit can heat the average Motorhome to temperature within 5 minutes
  • Cost efficient - If a litre of diesel is £1.30, the hourly running cost is approx. 13p. This can be further reduced using ‘red diesel’

The heater is installed in a suitable available space, hidden from view. We always attempt to locate the unit to our client’s requirements, however sometimes that is just not possible given the restraints of exhaust etc, but we will always offer suitable alternatives for the client to decide upon.

If your vehicle already has any other form of heating that uses air ducting the diesel heater can connect to that and provide heating via these ducts/ outlets.  If no existing heating or ducting is available, the heater is installed with its own.


The heater is controlled by a modern LCD user interface.

  • Fully adjustable fan speed control
  • Room temperature control, 15 degrees to 38 degrees (ambient) User set to desired temperature and heater will provide heating or sleep until room temperature drops below what you have set.
  • Timer function – the controller has 2 on/off cycles that can be pre-set to switch the heater on and off.
  • Error reporting – the controller can alert the user of any errors within the heating system – it is self-diagnosing.

" I don't want to see any unsightly wiring" Neither do our engineers! We apply a simple philosophy during the install, out of sight, out of mind and importantly, if this was my motorhome, would I be happy? The answer will always be YES to your total satisfaction.


The heater can be fuelled in two ways.

  1. Via a 10L plastic tank.
  2. Via a connection to the vehicle fuel tank (diesel only)

Option one has one major advantage over direct connection to the vehicle fuel supply. The ability to use 'Red' diesel. This can dramatically reduce fuelling cost with red diesel being approx. 55p per litre.  That said, it also depends on locating a reliable source/ supply of it. Obviously if your vehicle is petrol, then this is your only option. Be aware that having an internal plastic tank can and will lead to the smell of diesel within your vehicle. The tank is vented to allow us to draw fuel from it. Be aware that you may smell diesel within your vehicle from this tank as it is vented.

Option two - direct connection to vehicle tank is adventitious as it eliminates the need to carry any other fuel container and ensures no smell of diesel with the vehicle.  Direct connection to the vehicle tank is additional to the kit and costs £75 and can be selected on checkout. Why? Connection to your vehicle tank will take our engineer approx an hour more to fit and also requires a tank standpipe for connection.

Our units are designed to function in the harshest of environments thus ensuring that it is functional when the need demands heat.

The heaters are fully CE certified for use with the UK leisure industry and all our mobile engineers are fully qualified to install and maintain them.


The heaters are supplied with a full 12 months warranty, both parts and labour.

In addition to this, we can offer an annual maintenance contract for £99.00 This includes a service at the start of each season/ contract renewal. Please ask our engineers for full details.

Still got questions? Give us a call, we will be more than happy to assist.

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Our exclusive Challenger C series diesel forced air heaters can and will heat the average motorhome to 24 degrees in roughly 5 - 6 minutes. Can your existing lpg Truma do that?  Can it do it while you drive?  Challenger can! Ask your rear traveling passengers just how cold in can be back there. 

HEATER SIZES - What is best?

2kw - Small to medium sized vehicle / boat

4kw - Medium / large sized vehicle - best all round performer both small, med and large vehicle / boat.

6kw - reserved for the larger vehicle/ boat, normally with multiple outlets required.


Grant Willoughby

Engineer turned up, assessed job, spent a few hours working on motorhome fitting Challenger 4 kWh heater.

Was pleasant and informative and answered all my questions, couldn't have asked for more. All I had to do was supply a few cups of coffee.

Wish my experience of tradesmen over the last few years was as pleasant and reliable as this. Many thanks and would not hesitate to recommend ACLS to other van users.

Elaine McPherson Over the moon with the job and professionalism of fitter.

Amazed at the heater, well worth the money spent , thankyou, 5 star quality service.


Brian Johnston Thanks to ACLS engineer for fitting there challenger 4 kWh diesel air heating to my motorhome today he did a first class job he explained every thing you need to know how to work the heating system i would recommend ACLS from ordering to the fitting if you want a diesel air heating for your motorhome or caravan call ACLS thanks again Brian


Tommy Christie Great job had it running for two hours toasting going to have a lot of fun during the winter 35 degrees if I want highly recommend !!!!

John Herriot Thank you for your time,banter and a superb job,
After you left I filled up with fuel and food and on my way to try it up at loch Rannoch 


Andy Stott nice job 👌

Bob Bertram Many thanks for today Steve 
Top quality fit out and professional service . Looking forward to using the campervan through the winter months now on snowboarding trips in Scotland with that cosy 4kw heater . All the best to ACLS team . 

Katie Louise We love it and can’t wait for our next trip

Darren Waite I would just like to say a massive thank you to Steve for travelling all this way down to Huddersfield to fit our new 4kw diesel heater ready for our trip to Austria, a clean and professional fit out and so happy to recommend to others, thanks again Steve

Bernard Greedy I had mine fitted 2 weeks ago and just love it !! Make lots of cups of coffee for the lad who fits it !! He has time to talk to you if you need to ask any questions he will answer them fully !!