Condensation On Ductwork In Attic

The warm moist air trapped inside of your home is coming into contact with the cold wooden surfaces in your attic forming large damaging water droplets.

Condensation on ductwork in attic.

Ductwork located in an attic must be hung properly so that the insulation can do its job. Even though the air conditioning equipment appears to be operating normally humidity inside the house is between 60 and 65 and return ducts located in the attic show significant condensation. The colder the air is inside the duct the greater the chance of ductwork sweating. Condensation will begin to drip onto your attic insulation making it less effective at regulating temperatures inside your home.

The last usual cause for condensation on a duct system is if the ducts are not properly hung or they are touching each other. The 1 746 square foot house has r 19 insulation between the rafters and between r 15 and r 20 of rigid foam above the roof sheathing. First water dripping off of your ducts and onto your insulation can cause the insulation to compress which decreases it s r value or ability to insulate. When the hot humid attic air contacts the cold duct or the cold duct boot the moisture in the air condenses on the cold surface just like the condensation that happens on a cold can of beer.

Condensation forms on the outside of the glass where the cold glass is coming into contact with the warm humid air. When water condenses and drips into your attic or home it can cause a some serious secondary problems. It s a natural process and similar to the way a chilled soda begins to sweat once you take it out of the refrigerator on a hot day. There are two main ways to solve this problem.

Let s say your ductwork is in your attic. Recently i had another hvac company come out and put in a new bathroom vent and they told me they believed the duct work was full of water. Dripping condensation may also lead to a ceiling leak which not only looks bad but also rots drywall and can cause your ceiling to collapse over time. When ductwork is touching it forms a very cold spot where they are touching thus condensation begins.

The same thing may be happening on the inside of your attic. Condensation forms when warm moist air comes into contact with cool surfaces. Vapor barrier on the attic side of the duct s insulation is compromised. The attic ductwork is flex duct work.

I called out the original hvac company and they took a look and said they saw no water. It was new when the ac was put in 7 years ago. Moisture goes right through the fiberglass insulation and condenses on the inner liner drips on ceiling below after building up.