The one thing that pisses me off more than rattling interior pieces is fogged up windows. They fog up when it's not even that cold out. What can I do to prevent this.. it's on the inside of the windows.
The main thing is that the windows have to be super clean. Any residue on the glass and they fog up a lot quicker than it seems they should. Mine get coated about every 2 months with grime just from the open vents. Beyond that, crack your windows to let moisture out now and then... fog has as much to do with moisture balance as it does outside temp.
The fogging problem is waayyyy worse down here in the south where the humidity reaches 100% pretty much every day. The more moisture you have in the air, the more likely your windows are going to be fogging up. If the air is cooler in your car than the outside, you won't have a problem. But seeing as I HATE running my AC, I get alot of fogging because I roll with the windows down.
If you run your AC every now and again, you shouldn't have a problem. If you don't feel like running the AC, I would just listen to everyone else.
I have to laugh, because the fogging problem is very true on the Focus. It happened in the old ZX3 I owned, and it's happening again with this newer one. Thankfully the defogger in this newer one is working a lot better. The only problem is it's freakin' cooooold! But then again which would you rather choose: freeze to death in your own car, or kiss a telephone pole you didn't see while doing 40? Heheh.
Puro Latino, TMI but still very true. LOL! So as everyone in the universe has pretty much said, keep the inside of your windows clean and your fogging problem will be greatly reduced.