Condensation In Attic Ductwork

Ductwork located in an attic must be hung properly so that the insulation can do its job.

Condensation in attic ductwork.

If not condensation will form in the ducts when the heat hits the cold duct. 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. 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. Also whenever you cook and especially when you take a shower this will dump additional moisture into the attic ducts.

The attic ductwork is flex duct work. The air in your vented attic is hot and humid just like all outdoor air in florida. 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. When ductwork is touching it forms a very cold spot where they are touching thus condensation begins.

All you need is a sag in the line or a level area and water will accumulate. 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. 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. Condensation forms when warm humid air comes into contact with a colder surface like your air conditioner s ductwork.

The colder the air the more likely it is that water will condense. The colder the air is inside the duct the greater the chance of ductwork sweating. 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. Vapor barrier on the attic side of the duct s insulation is compromised.

Moisture goes right through the fiberglass insulation and condenses on the inner liner drips on ceiling below after building up. 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. As the humidity level rises outdoors condensation will gradually begin to form on the surface of your air conditioning ducts.

Let s say your ductwork is in your attic. Condensation forms when warm moist air comes into contact with cool surfaces. Condensation forms when the water vapor in the air drops out of suspension and condenses into a liquid form. There are two main ways to solve this problem.