I am getting moisture on my windows. I run a dehumidifier and get 40 pints of water in 24 hours. I have vent in my bathrooms and above my stove. I have a 1986 model Carrier Weathermaker SX furnace. I contacted my furnace man and he said that they had some trouble with this model furnace creating moisture in some air tight houses as mine is. He suggested that I run a 4 inch plastic pipe from the outside of my house to the return air plenum 2 feet up from where it goes into the bottom of the furnace. Can anyone please give me any insight on this?