Best Way To Insulate Heating Ducts In Attic

Check the speed of the blower motor on the furnace.

Best way to insulate heating ducts in attic.

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. Use a paintbrush to apply duct mastic to the joints where an elbow connects to a duct. By spraying closed cell foam on the ducts before burying them in attic insulation you prevent the condensation problem. When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value.

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. 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.

Duct board much like the duct liner is also a fiberglass product. Duct liner isn t generally a diy installation and if your ducts already have liner you don t need to insulate the exterior. 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. Unconditioned attics are the worst place to put ducts.

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 you re facing that as one choice for a new home or if you already have that in your existing home here are some ways to reduce your duct losses. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. Get the ducts out of the attic and into the conditioned space below.

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. Ted has more than a few cobwebs in his attic. Make sure the foil surface of the insulation is free of dust before applying the tape.

Doing this results in zero additional load.