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Autoterm 2kW vs 4kW, which diesel heater is right for me?

Updated: May 9, 2022

Autoterm make the best diesel night heaters on the market, which is why we endorse them. However, there are a few choices to make when it comes to choosing the perfect van for your vehicle.

With diesel heaters, bigger is not always better!

To choose the perfect heater for you, you should consider a few factors, such as:

  • Will you be doing ski seasons or a lot of very cold winter travel?

  • Size of vehicle- Is your living space over 16 cubic metres?

  • Will you be using your heater heavily for water heating in summer?

  • Do you have lots of windows or the cab open which could lose a lot of heat?

Diesel heaters have a maximum and minimum power. For the 4kW, the lowest power setting is 1kw, with the 2kW power level being about half of this. Choosing the incorrect size heater means that either the heater runs on full all the time and never achieves the desired temperature, or constantly has to turn itself on and off in order to keep the temperature low enough, wasting fuel and power.

If you have answered yes to one of the questions above, then the 4kW is for you. However, if you have a small van or don't fit the criteria then don't be tempted to go for the bigger heater 'just in case' as the 2kW will almost certainly be sufficient. Bear in mind the 2D is smaller, quieter and much easier to install than its bigger brother as the amount of fitting locations is greater, a 2kW will fit happily under a Ducato drivers seat or a Sprinter passenger seat whereas the 4kW will be trickier to site due to its size.


There are three options for Autoterm controllers: The Rotary controller, the Comfort controller, or the Rotary controller with thermostat.

Comfort controller

The Comfort controller is Autoterm's latest controller and features a range of heater control modes including full thermostatic control, daily or weekly timers and a modern, intuitive display. Whilst it is full featured, it does lack simplicity and turning the heater on isn't a one button operation.

Rotary controller - PU-05 Simple

The rotary controller is the simplest controller available. Press the three arrows and the heater comes on at the power level on the dial, until you press the same button to turn it off. Likewise with the fan button, if you press it the fan runs (ventilation mode), then turns off when you press the button again. Brilliantly simple, but needs constant adjustment to maintain the correct temperature.

Rotary controller with thermostat

The third option is to add an extra temperature sensor to the PU-05 Simple controller. This means that the heater will maintain temperature according to the feedback from the controller, constantly adjusting the heaters output. If the cabin gets too hot the heater will shut down, restarting when the temperature has dropped down past the desired point. This is our favourite combination as it combines the simplicity of the roraty controller with true thermostatic control and therefore comfort!

Whichever heater you go for, do ensure you have a working carbon monixide alarm in your vehicle. If you have any questions or comments then get in touch at or use the contact form on the website!

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