Cost-effectively turn an auxiliary heater into a parking heater - that's what Webasto offers for a great number of diesel vehicles. What's more, the Webasto auxiliary heater installed ex factory, can be retrofitted with an upgrade kit so the device can then be used as a parking heater. The result: improved mileage for the engine, more safety thanks to ice-free visibility and comfortable warmth when you get in to the vehicle.
Since modern-day diesel engines operate very efficiently, only very little waste heat is generated for heating the interior. Therefore, many diesel vehicles are factory-equipped with an auxiliary heater that already has many of the components of a parking heater. With a vehicle-specific upgrade kit and the desired control unit, the auxiliary heater can be inexpensively and easily upgraded to a parking heater. The time required for installation of the upgrade kit varies by vehicle, but usually doesn't take more than three hours of work. See an overview of the upgradable diesel vehicles here.