Well my B6 1.8T Q handled the summer very well blowing out ample cool air on hot days. Now winter is upon us in Atlanta I am running my climate control around 75, and on cold days all the way to 'Hi'. However, the problem is the car is not producing any hot air. My commute for work is approximately 35 mins and during this period it does not change. After about 15 mins of driving, there is a feeling of somewhat warm air but by no means hot. I find myself driving with a coat on, which I dislike. My wife dislikes taking my car now as it always feels chilled, so we end up in a Volvo!

I am looking for advice on where to start without going to the dealer for a diagnostic. I have no error codes on the dash. Is there a simple thermastat or similar part I can purchase from an auto store and replace myself to see if it rectifies the problem? Any suggestions are greatly appreciated.