Best Way To Insulate Heating Ducts In Attic

Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.

Best way to insulate heating ducts in attic.

Duct liner isn t generally a diy installation and if your ducts already have liner you don t need to insulate the exterior. Get the ducts out of the attic and into the conditioned space below. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. 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.

Duct board much like the duct liner is also a fiberglass product. 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. When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value. Ted has more than a few cobwebs in his attic.

The unconditioned space also houses his hvac system. Plan to pull up the flooring and layer new insulation on top of the old. The doe s building america program recommends beds buried encapsulated ducts. Heaping insulation over the ducts is fine in dry climates but can cause condensation on the duct insulation jacket in humid climates.

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. Use a paintbrush to apply duct mastic to the joints where an elbow connects to a duct. Doing this results in zero additional load. Because the simplest and cheapest way to insulate an attic is to add material to the floor.

If necessary switch the wires to reduce the blower to its lowest speed. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. Make sure the foil surface of the insulation is free of dust before applying the tape. Unconditioned attics are the worst place to put ducts.

Sometimes metal ducts are lined with duct liner a 1 inch thick fiberglass board that insulates the interior of the duct rather than the exterior.