When the engine is off and you want to stay in the car, you can choose to use the heat generated from your drive to keep the passenger compartment warm.
Note
The amount of residual heat available limits how long the passenger compartment can stay heated in a cold climate.
Press the fan symbol in the bottom bar 
.
.Press Use heat from drive.
The car uses heat generated from your drive to keep the passenger compartment warm.
Press Stop using heat from drive to turn it off.
The heating is automatically turned off when you lock and leave the car.