Webasto
Webasto Air Top, Webasto Thermo Top, diesel parking heater, auxiliary heater, diesel air heater
Webasto is a German brand of auxiliary heaters; in van life it usually refers to a diesel air or coolant heater installed in a van or motorhome.
In everyday speech, “Webasto” is often used generically for almost any diesel heater, even from another manufacturer. Air Top heats cabin air directly; Thermo Top heats a coolant circuit or heat exchanger.