How To Insulate Ductwork In Attic

When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value.

How to insulate ductwork in attic.

Recently i had another hvac company come out and put in a new bathroom vent and they told me they believed the duct work was full of water. Cover the spray foam with fire retardant spray. 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. The attic ductwork is flex duct work.

This isn t equivalent to bringing them into the conditioned space as you ll still have additional duct load but it s a lot better than having them in unconditioned attic space. Use a pressure sensitive vapor retarder tape designed for ductwork. Make sure the foil surface of the insulation is free of dust before applying the tape. Avoid compressing the insulation.

Energy saver dealers 204 202 views. It was new when the ac was put in 7 years ago. That s what happened to the ducts in the lead photo of this article. Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.

Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. Mechanically fasten and mastic seal all duct connections. If you want to cover metal ductwork with blown in insulation t hese steps must be followed in this order. The duct insulation should include a vapor barrier cover.

Bury the ducts deeply in insulation. Use a paintbrush to apply duct mastic to the joints where an elbow. If necessary switch the wires to reduce the blower to its lowest. Most insulation relies upon the air space between its fibers to deliver the r value promised.

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. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. Tape any punctures in the insulation s vapor barrier to prevent leaks. Use metal flex or fiber board ducts that are insulated to code.

Plan to pull up the flooring and layer new insulation on top of the old. Because the simplest and cheapest way to insulate an attic is to add material to the floor. The foam provides a vapor barrier so the ductwork won t sweat. Check the speed of the blower motor on the furnace.

Cover the metal ductwork with closed cell spray foam.