Insulated Ductwork For Attic

First consider the duct location.

Insulated ductwork for attic.

Covering ductwork with insulation. In this video this old house plumbing and heating expert richard trethewey helps a homeowner insulate his ductwork. When these ducts are exposed to exterior air the plastic jacket never gets cold enough to permit condensation because the hot attic air keeps the plastic jacket warm. Check the speed of the blower motor on the furnace.

The greater the temperature extreme between the air inside the duct and the air surrounding the ductwork the greater your need for duct insulation. 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. Use metal flex or fiber board ducts that are insulated to code. 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.

Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. Today s flexible ductwork is covered with a shiny metallic cover this is its vapor barrier. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. Is it ok to do it.

The shiny vapor barrier will protect the ductwork from sweating as long as it s exposed to the surrounding air. The duct insulation should include a vapor barrier cover. Unfortunately so many houses especially newer homes end up with ductwork running through the attic. If necessary switch the wires to reduce the blower to its lowest speed.