This will probably be hard to diagnose without seeing the problem but I though I would run it by you guys since the HVAC tech wasnt sure what to do. I have a lennox heat pump with the furnace in our garage. It is an upflow unit so the filter is at the bottom of the unit with the coils and drip pan just above. About a month ago when I went to change the filter I noticed some water was dripping onto the filter. It wasnt a whole lot but enough to cause a little mold growth on the filter. I called the hvac tech and he thought it was the condensation drain line sweating and dripping onto the filter. He came out and wrapped more insulation around the pipe. I mentioned to him I didnt think thats what it was but he isisted it would fix the problem. Well, I check the filter last night and sure enough there was more water on it. I noticed there is some wrapping underneath the drip pan and when I pulled the wrapping down just a little water came out. It looks like water is builidng up between the wrapping and the drip pan. I dont think it would be a leak since the unit is only 2 years old and the pan is plastic. Could the pan just be sweating underneath? Has anyone ever seen anything like this. I just want to know what I cant tell the hvac tech to help him diagnose the problem. Thanks for the help.