Have in the past had the same problem. I have done two things that have vastly improved my plight.
- Fitted wind deflectors and run with one, if not both windows opened an inch or so.
- Re-fitted the dash mounted fresh air vents after a previous owner had removed them for speakers.
Also run with the air directed at the screen, even if the fan isn't on.
Agree with the comments about not wiping the windows. We went to a gig last week in a friends car; he and his wife routinely demist their car with a grubby old cloth. It would appear they rarely use their heater, even on low. The result was that on a cold November evening all the windows had streams of condensation running down them, leading to more wiping and even more condensation.
Edited by humph, 25 November 2014 - 01:47 PM.