Published on December 4th, 2012 | by Henri0
Ductwork sweats and drips
Q. The warm-air furnace with air conditioning is in our basement. In the summer, there is a severe and intolerable damp mildew smell in the basement. The ductwork closest to the unit sweats and drips onto the floor and we believe that this is the origin of the odor. Is there a way to remedy this smelly problem? We have bought a top-of-the line dehumidifier but it has not taken care of the problem.
A. A dehumidifier would be the solution I would suggest but since you have one and it does not take care of the problem, you should have the plenum on top of the furnace and all accessible supply ducts in the basement insulated.
Obviously, your condenser is fully-charged and operating efficiently, thus sending very cold air through the plenum and the supply ducts. Insulating these ducts would push the problem further down the line but the inaccessible supply ducts to the first floor registers are very short.
Those to the second floor (if your house has one) have such a small cross section that the cold air going through them would cool the surrounding area enough to prevent the dew point and condensation.by