Originally Posted by PuyallupCoug
Try running your A/C when you get moisture/condensation in the car. A little known characteristic of Air Conditioning is that it actually de-humidifies the air. Don't worry, you can still have the heat on at the same time as A/C doesn't necessarily mean "cold air".
A lot of foggy windows in the wintertime can be solved by simply activating the A/C.
It's also not a bad idea to run the AC a few times throughout the winter. It will help keep the compressor lubricated and extend the life.
In other news, it was 26F and the washer fluid Subaru filled my tank with at my last oil change has frozen on my windshield.