In colder countries you can have a 'parking heater' - this can be turned on to warm up the car before you get in, in Germany they refer to these as auxiliary heaters.
As said here, there is a engine pre heater which in this country we refer to as an auxiliary heater, which is found on diesel cars. It's a pre engine heater in effect.
If you look on the German VW site and spec a GTD you will see the option for a 'parking heater'.
James