The Heatpump (A/C) can be used to both warm and cool the car more efficient. In fact the AC (like in homes) does both jobs. Turning it off would disable the heat from the heatpump...I have the same problem.
I went to my kia dealer and they told me to have the a/c and heat buttons "on" to get heat from the system.
It seems to work untill you switch off the a/c. The it starts to blow cold air even with heat button active. If you turn a/c again with heat button active you won't get any more heat until you stop the car, switch it off, get out and lock it. And then get in the car, start again etc etc...
Did you find a solution? Any advice?
While most people in the car think it is only for coolling as heat was coming from the engine. For electric that won't work