Inside Window Frosting

I have a 2001 330i with 69k miles. Recently I have experienced having that haze which shows up at the inside bottom of the front window and along the side front windows. The coolant has gone down ever so lightly and required small refills once a week. Radiator, tank and water pump were replaced at 60k. This usually means there is a small coolant leak somewhere. Possibly in the heater core or hose lines under the dashboard. I have taken apart all this and found nothing out of the ordinary. The heater core tests fine. I will be replacing the necessary o-rings when reassembling the items. Side note, the a/c has not cooled perfectly for past 2 years and I don't know if this may be a related problem. Any other insight?