Condensation On Ductwork In Attic

During periods of high humidity and high temperatures the conditions are ideal for condensation to form on improperly insulated ductwork in your home s attic.

Condensation on ductwork in attic.

There are two main ways to solve this problem. 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. 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.

It was new when the ac was put in 7 years ago. 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. The air in your vented attic is hot and humid just like all outdoor air in florida. 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.

The same thing may be happening on the inside of your attic. 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. Condensation forms on the outside of the glass where the cold glass is coming into contact with the warm humid air. 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.

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 attic ductwork is flex duct work. When water condenses and drips into your attic or home it can cause a some serious secondary problems. When ductwork is touching it forms a very cold spot where they are touching thus condensation begins.

Ductwork located in an attic must be hung properly so that the insulation can do its job. The colder the air is inside the duct the greater the chance of ductwork sweating. Moisture goes right through the fiberglass insulation and condenses on the inner liner drips on ceiling below after building up. As the humidity level rises outdoors condensation will gradually begin to form on the surface of your air conditioning ducts.

Condensation will begin to drip onto your attic insulation making it less effective at regulating temperatures inside your home. Vapor barrier on the attic side of the duct s insulation is compromised. I called out the original hvac company and they took a look and said they saw no water.