Trying to understand how the Model Y heater works. I am wondering if there is something wrong with my heater or if it is the way heat operates on an electric car. Typically, the heat works very quickly when preheating the car, but it will intermittently blow cold air and then hot air again to control climate. The cold air is very noticeable and it is enough to make my feet cold and not recover when it blows hot again. Also, when I get on the interstate it will blow cold air for at least the first couple of minutes every time before it will switch back to warm air again. Finally, the past couple of days I have preheated by car for about 10 minutes (very cold outside, around 15 degrees Fahrenheit), and when I get to my car it has not warmed up at all even though in do not have any faults. Is this typical operation of the heater or does service need to look into this?