Without seeing your duct attic situation one can only speculate but ducts touching each other lying on or in insulation in our climate.
Condensation in attic ductwork in winter.
But i notcied that the condensation only formed when the outside temps fell below about 20 degrees.
Think about it condensation on ductwork probably isn t a big problem in phoenix arizona but why.
Even though the ducts are insulated and my attic is over insulated the air and surfaces inside the ducts will get very cold if the hvac is left off.
Condensation problem in the ductwork in wintertime question i have a dedicated ductwork system with the air handler in unconditioned attic.
When outside temperatures drop down below about 40 pretty much nov thru march condensation starts forming in the ducts and drips from some of the ceiling registers.
But at a premium cost.
No the radiant barrier will not solve the condensation issue.
It can also feed mold growth and cause ceiling joists to rot and sheetrock to disintegrate leading to unhealthy air quality in your home and the need for costly structural repairs.
When the warm air rising from the first floor gets into the duct inlets a lot of condensation forms.
Because the average humidity level is 10 20 in phoenix.
If the attic is foam sealed with no leakage to the outside that would work.
The house air with its moisture rises into the ducts cools and condenses the moisture cool air sinks and is replaced with more warm moist air from inside the house.