Insulating Heat Ducts In Attic

Because the moving air is in the ductwork for only a short period of time it does not need the insulation r value the attic floor requires.

Insulating heat ducts in attic. Make sure the foil surface of the insulation is free of dust before applying the tape. The greater the temperature extreme between the air inside the duct and the air surrounding the ductwork the greater your need for duct insulation. First consider the duct location. Of course you might also consider replacing your old ducts.

When the attic is 20 f that insulation is addressing a delta t of 50 f. Other times insulation may be on the outside. So logically the ducts deserve more not less insulation. Flexible ductwork comes with different insulation r values.

Replacing your ducts is another option when you ve got old uninsulated ones. Because the simplest and cheapest way to insulate an attic is to add material to the floor. Out with the old in with the new. Use a paintbrush to apply duct mastic to the joints where an elbow.

But if the floor is covered in plywood you can t stuff enough insulation beneath it to do the job sufficiently not even in warm climates. When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value. Unfortunately so many houses especially newer homes end up with ductwork running through the attic. Acute temperatures in these areas contribute to thermal loss in metal ductwork.

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. After all most new homes have r 49 insulation on the attic floor holladay continues. 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. Wrap fiberglass duct insulation around the ducts and tape the seams together.

If necessary switch the wires to reduce the blower to its lowest. Check the speed of the blower motor on the furnace. Plan to pull up the flooring and layer new insulation on top of the old. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords.

But the air in the ducts is facing a delta t of maybe 100 f or 120 f a greater delta t. But whether you hire us or somebody else be sure your contractor follows these steps. Our team follows a rigorous process for replacing ductwork. 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.