I have a 2009 VW Rabbit, and lately (as the temperatures have gotten colder), the inside of the windows often fog up. Particularly, the front windshield tends to build up quite a lot of fog on it. Also, cleaning it seems to make it worse rather than help, as fog tends to build up where I clean it, and many cleaners leave smears on the glass. Sometimes, the fog on the inside of the front windshield is so thick that I can almost see droplets of water forming.
A couple days ago, I bought some auto window cleaner, a microfiber window cloth, and Rain-X anti-fog. I cleaned the inside of the windows and then applied the anti-fog. The windows seemed nice and clean until tonight, when the windows fogged up on the inside again. The front windshield was pretty much totally covered with fog and smears from the glass cleaner.
I'm not sure if I'm not cleaning the windows correctly or if there's a moisture leak or if there is moisture trapped inside my car. Are there any special techniques, cleaners, or towels I could use to help prevent interior fog buildup? Or could there be a more serious issue? I'd rather not leave my defrost & A/C on all the time to de-fog my windows.