Auxiliary/standalone heater (option code 228) only offered in colder climates, never offered in North America. The heater used by MB is popular product by name "Webasto". Webasto burns petrol, (or diesel) in a heater located in the engine bay. The exhaust smoke comes out from the bottom of the front bumper. It also turns on the interior fan blower, to heat up the inside of the car as well. In the summer, only the blower fan is started, to circulate the air. The coldest temperature you can get is the outside temperature.
Auxiliary heater comes with another MB remote to control it from 300-400m away. It allows to turn power on or off. If turned on, the heater will run for 50 minutes, and then automatically turn off. Inside the car it is possible to set three different timers, but they are not daily, they have to re-set everyday for it to work. There's another version of Webasto Telestart which comes with remote control that has a non-color LCD screen and allows to remotely set timer.