Living in Vermont, I'm hyper-aware of my car's heating system, heated seats, heated mirrors, etc. How does the Model S heater derive its heat? From the coolant loop or from a heating element? For energy conservation, I imagine that it uses the coolant loop. If that's the case, does it take longer than an ICE car to warm the interior in sub-freezing temps? Does the battery and motor start warming up right away, even at in-town speeds? If the car is left plugged-in at night, perhaps the battery would be warm already from charging.