I have been fighting fogging windows and have tried Rain X and all the other over the counter solutions with very little effect. I found a solution that has been working very well. It is a film similar to tint but designed to keep fog off windows. Initially it was designed for freezer doors in grocery stores and they are now marketing it to the automotive industry. It is not cheap at $20 a linear foot but it is really nice being able to see out the windshield. Don't get me wrong there still gets minor fog but then again so does my new Range Rover.
The product is offered by Pro Tint and the link is below.
http://shop.protint.com/category.sc?categoryId=29
The product is offered by Pro Tint and the link is below.
http://shop.protint.com/category.sc?categoryId=29