The VW T6 is availabe either with warm water parking heater or air parking heater. You can't order both heaters at factory. However, even when your car has already an air heater, it will most certainly have an auxiliary water heater too.
This water heater can be upgraded to a parking heater with our upgrade-kit. The installation is done within a couple of minutes due to our simple plug&play connection. You don't have to cut any wires or change any software of the car.