Heating and Ventilation

My heater doesn't work.  The car does not over heat at all.  it runs at the normal middle of the road temperature.

Could it be that there is not enough coolant in the system, or is the thermostat on the engine cooling system not working properly????

Thank you for your help!

When ac is on my front window fogs on the outside requiring me to use winshield wipers to clear. I have tried all the different switch blowing patterns. Any suggestion ? I had it in for 20,000 mile checkup and mentioned this but Porsce dealer did not check it. Initially he said it might be humidity controls.