This is my first Minnesota winter in my Roadster and I'm not sure if my heat is working properly. It was -2 degrees today for an hour long drive I had and the car felt like it never got above 40 inside the cabin (thank god for heated seats). Usually when I use the heat I can only leave it on for a few minutes at a time until it is absolutely roasting inside. Would this cold weather affect the heater so significantly? Is it possible there is a problem? What do you other cold weather Roadster owners experience? And yes I had the top on the hardtop.