Insulating Ductwork In Attic Venting

Flexible ductwork comes with different insulation r values.

Insulating ductwork in attic venting. The greater the temperature extreme between the air inside the duct and the air surrounding the ductwork the greater your need for duct insulation. Ted also has inherited a powered attic ventilator. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards that specify an r value of 8 for attic ducts and 6 for ducts located anywhere else. Sometimes the insulation is inside the ductwork.

Unfortunately so many houses especially newer homes end up with ductwork running through the attic. The 1 800 square foot brick ranch in climate zone 4 dates from the 1960s but the previous owner installed both a furnace and ductwork in the attic just four years ago. Other times insulation may be on the outside. Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.

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. Make sure the foil surface of the insulation is free of dust before applying the tape. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords.