Frequently Asked Questions

Fuel autonomy: diesel fuel is uniform worldwide and available 24/7, all year long. A very precise monitoring of fuel supplies is possible via the fuel-gauge. Heating autonomy: heating while driving is allowed worldwide. By supplying the heater with diesel out of the vehicle fuel tank, there is no need to search for fitting bottle connectors or hassle of exchanging gas bottles in foreign countries. More space: gas bottles in motorhome can be reduced as they do last longer anyway and all Webasto heaters can be mounted outside the vehicle. This leads to significantly more space inside the motorhome. Less weight: in winter, more than 80% of LPG gas is needed only for interior heating. By using diesel operated heaters, the LPG gas bottles can be downsized to one single 5 kg bottle and up to 35 kg of additional load can be gained.

The technology of diesel heaters made big steps forward since the first heaters were introduced. Together with specially configured motorhome heaters, Webasto provides silent application kits whose various accessories eliminate all possible disturbances (i.e. exhaust silencer, ultra-silent pump, etc.), for your comfort and the comfort of your campground neighbour.

No! Webasto heaters do not need a catalyser thanks to the very effective burning process. The exhaust values of our heaters are already on a very low level within the legal requirements.

Yes! Heating while driving is allowed worldwide for all our heaters! This way you can have a cosy and warm interior already when arriving at your holiday destination.

Yes! All Webasto heaters are tested and approved to work reliably up to 1,500 m which is sufficient for most European mountains. The Air Top Evo and Dual Top Evo range even work up to 2,200 m thanks to the integrated automatic altitude sensor. The Air Top 2000 ST is optionally equipped with an integrated switch for altitude operation of up to 2,200 m.
For altitudes above 2,200 m it is possible to adjust our heaters. Please contact your local Webasto dealer for further details. Passing over the mountains while the heater is in operation, is not a problem for any of the Webasto heaters.

All Webasto heaters are tested and approved to work in a temperature range from -30 °C to +40 °C or more. The fuel used in very cold regions where temperatures can fall considerably under 0 °C (arctic diesel or winter diesel) is automatically mixed with additives to prevent freezing of the fuel. Besides using this fuel, no special preparation of the heater is needed. Basically, if your vehicle can drive, your heater will run as well.

All Webasto heaters are tested and approved to work with the legally permitted biodiesel content. The usage of a higher content of biodiesel however will reduce the lifetime of the heater.

Generally no! Webasto heaters are maintenance-free and do not have to be inspected every two years. We only recommend operating the heater every two months for 10-15min. 

Yes! Webasto offers retrofit kits for all heaters. The kits contain everything that is needed to get the heater running, only vehicle-specific air ducting, mounting and fuel parts need to be added. Get in touch with our trained dealer network and ask for a bespoke quotation to retrofit a Webasto heater to your motorhome. Even if you are equipped with an LPG gas heating system it may be wise to have some redundant diesel heating system in order to heat quicker and with more power.

There are different possibilities when it comes to additional heaters:  large (e.g. integrated) motorhomes usually lose the majority of heating energy through the windscreen. The big windscreens are not well isolated and condensation water concentrates in this area. Also if you turn drivers and passenger seat to the dinette you may feel cool air from the back.
In order to avoid both, the Thermo Top C Motorcaravan heats specifically the driving cab and reduces the accumulation of condensation. It is mounted into the engine compartment and the air is distributed through the vehicles own fan system.
Also an additional air heater makes sense when your existing heating system is not sufficient enough or if you’d like to feel secure on holiday by not having to rely on your LPG gas supplies.  You can use the larger Webasto heaters to either heat the entire motorhome or you can use the Air Top 2000 ST when a bit more power in the front area is needed or to warm other parts which are not well reached by the existing main heater.

The Webasto heaters need to be installed by an authorised dealer. Otherwise any warranty or liability for damages or repairs may be refused.

Webasto heaters are designed and validated to be mounted outside the vehicle, for more valuable space inside. Air Top & Dual Top heaters can be mounted underfloor, into the double floor of the motorhome or inside the cabin. The Air Tops can even be tilted up to 90° if necessary. Thermo Top C heaters are usually mounted into the engine compartment or under the motorhome.

No! Thanks to the E1-approval, which is granted to all Webasto heaters, it is not necessary to make any technical inspection or registry in the motorhome registration documents.

Each heater has its own fuel system with a dosing pump which takes the fuel directly and independently out of the vehicle fuel tank.

Of course, the fuel consumption is strongly depending on the needed heating power and type of heater. As very rough and noncommittal proportion a heater needs 100 ml diesel per hour and kW. For further details, please see the heater’s technical specifications.
Evidently, the heater is only using fuel when combustion is in process.

No! The fuel connection of Webasto heaters uses the return pipe or a separate fuel tank extractor. The suction hose will not reach the fuel tank ground so that a reserve in the fuel tank is always secured.

The electrical consumption is depending on the heating power needed and the type of heater. For further details, please see the heater’s technical specifications. The Air Top 2000 ST, for example, needs only 14 to 29 W. To maintain the temperature once set point is reached, the electrical consumption is at the lower level. With these low electrical consumptions, you can sleep quietly and do not have to worry about your heating autonomy.

No! Webasto heaters are equipped with an undervoltage protection and shut down before critical battery conditions, so that an engine start is still secured. Motorhome heaters are anyhow usually connected to a secondary battery and do not have any impact on the engine start.

A temperature sensor, connected to the heater and positioned at an inconspicuous place inside the vehicle, constantly measures the interior temperature so that the heater can automatically adapt the air volume and heating power to the needed level.
The temperature measurement can be disturbed when the sensor is covered up by a curtain or if the sensor is exposed to sources of heat such as direct sunlight, interior lighting or the stream of heated air. If you experience this, it may be useful to relocate the sensor.

Yes, but not entirely. To ensure that no damage is caused, a Webasto ducting of min 1m at the outlet side of the heater and an even air distribution are required. If you want to be on the safe side, use Webasto air ducts that securely withstand the temperature ranges of the heater.

Yes! The connection of a Thermo Top Evo to an Alde heating system is possible in case the Alde plate heat exchanger to the engine is installed, which brings a few more advantages to the heating system, but it is also quite complex. Please make sure that only Webasto-trained personnel performs such an installation.

Yes! By incorporating a plate heat exchanger or an additional boiler, it is possible to heat sanitary water as well. However, such solutions need to be planned and carried out individually. Please contact your Webasto Service Centre in case of interest.

Yes! The Thermo Top Evo can be used to preheat the engine when they are incorporated into the vehicle coolant cycle. When the cabin is warm enough, the thermostat valve opens and the engine is also heated up by the hot water.

The Dual Top comes with an integrated 11l water boiler positioned around the heater core. By heating the heat exchanger, the warmth is transferred into the water. The desired water temperature can be selected between 40 °C or 70 °C.

Yes! It is not necessary to have water in the boiler when heating the cabin only. If the mode “Water + Cabin Heating” is selected and there is no water in the boiler, the Dual Top will automatically switch to “Cabin Heating Only” and indicate at the control panel that there is no water in the boiler.

Of course, the heating time depends on the water temperature inside the boiler, the selected temperature and the selected heating mode. When heating water only, warm water is available already after 20 min.
When heating the cabin and water at the same time, the Dual Top focuses on heating the cabin first. As soon as the vehicle’s interior has reached the desired temperature, the hot air fan stops and the Dual Top continues heating the water until it reaches 70 °C. In this case, it is advisable to turn the heater on approximately one hour before hot water is needed.

Depending on the quality of the water that is filled in or the time the water remains inside the boiler, it may be necessary to descale or disinfect the boiler from time to time. For more detailed information on how to descale or disinfect, please see the Dual Top operating manual.

No, due to the complexity of the heater, it is not possible to retrofit a standard Dual Top version with electrical coils afterwards. But Webasto offers two Dual Top versions with integrated electrical coils that operate with 230 V and have an additional heating power of 1 or 2 kW.

No, it is not possible to connect them, because these are two different heating systems. The Alde or Thermo Top Evo is heating a water glycol mix that heats up air through convectors and heat exchangers and the Dual Top is heating air directly.