Insulated Ductwork For Attic

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.

Insulated ductwork for attic.

Check the speed of the blower motor on the furnace. First consider the duct location. 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. Today s flexible ductwork is covered with a shiny metallic cover this is its vapor barrier.

Is it ok to do it. The greater the temperature extreme between the air inside the duct and the air surrounding the ductwork the greater your need for duct insulation. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. The duct insulation should include a vapor barrier cover.

The shiny vapor barrier will protect the ductwork from sweating as long as it s exposed to the surrounding air. Although both the attic floor and the ductwork are insulated ted recognizes the situation isn t ideal. Use metal flex or fiber board ducts that are insulated to code. 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.

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. If necessary switch the wires to reduce the blower to its lowest speed. Hvac ductwork is typically visible in your attic especially flexible ductwork. In this video this old house plumbing and heating expert richard trethewey helps a homeowner insulate his ductwork.