The shiny vapor barrier will protect the ductwork from sweating as long as it s exposed to the surrounding air.
Insulated ductwork for attic.
Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords.
In this video this old house plumbing and heating expert richard trethewey helps a homeowner insulate his ductwork.
The greater the temperature extreme between the air inside the duct and the air surrounding the ductwork the greater your need for duct insulation.
If necessary switch the wires to reduce the blower to its lowest speed.
Most attic ducts are insulated flex ducts that is flex ducts with r 6 or r 8 fiberglass insulation along with an exterior polyethylene jacket.
Covering ductwork with insulation.
Is it ok to do it.
When hvac ducts are installed in a vented attic in a dry climate bury the ducts in attic insulation to protect them from temperature extremes in the unconditioned attic space.
Unfortunately so many houses especially newer homes end up with ductwork running through the attic.
Summer hasn t even arrived he notes in a post at gba s q a forum and when the temperature outside climbs to more than 95 f the temperature in the attic tops 120 f.
Check the speed of the blower motor on the furnace.
Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct.
Use metal flex or fiber board ducts that are insulated to code.
Today s flexible ductwork is covered with a shiny metallic cover this is its vapor barrier.
Hvac ductwork is typically visible in your attic especially flexible ductwork.
The duct insulation should include a vapor barrier cover.