Did the fogging start just after you had just started up the heater?

Well, I don't have any sort of working heater to speak of, the piece of crap that's in there was home made and since it doesn't work anyways, I unplugged it and installed my stereo system on it's power supply. As for the fogging up, it's always had a less drastic version of this problem, but just not as bad as the other night, which was brutal by the way. I don't know, maybe it was just the intensity of the moisture in the air? Anyways I think I'm going to try the Rain-X stuff, just to make sure it doesn't happen again, or at least less drastically!