Insulating Heat Ducts In Attic

Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct.

Insulating heat ducts in attic.

Use a paintbrush to apply duct mastic to the joints where an elbow. Out with the old in with the new. 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. Flexible ductwork comes with different insulation r values.

Replacing your ducts is another option when you ve got old uninsulated ones. 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. Sometimes the insulation is inside the ductwork. A metal duct conveying cool conditioned air through a broiling attic in summer or warm air through a chilly crawl.

When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value. When the attic is 20 f that insulation is addressing a delta t of 50 f. But the air in the ducts is facing a delta t of maybe 100 f or 120 f a greater delta t. Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.

Make sure the foil surface of the insulation is free of dust before applying the tape. After all most new homes have r 49 insulation on the attic floor holladay continues. 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. Our team follows a rigorous process for replacing ductwork.

Wrap fiberglass duct insulation around the ducts and tape the seams together. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. But whether you hire us or somebody else be sure your contractor follows these steps. So logically the ducts deserve more not less insulation.

Other times insulation may be on the outside. Of course you might also consider replacing your old ducts. If necessary switch the wires to reduce the blower to its lowest. Because the simplest and cheapest way to insulate an attic is to add material to the floor.

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. 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.

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.