How To Insulate Ductwork In Attic

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How to insulate ductwork in attic.

Make sure the foil surface of the insulation is free of dust before applying the tape. Plan to pull up the flooring and layer new insulation on top of the old. Tape any punctures in the insulation s vapor barrier to prevent leaks. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords.

Most insulation relies upon the air space between its fibers to deliver the r value promised. Check the speed of the blower motor on the furnace. The duct insulation should include a vapor barrier cover. I called out the original hvac company and they took a look and said they saw no water.

Mechanically fasten and mastic seal all duct connections. 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. Use a paintbrush to apply duct mastic to the joints where an elbow. Avoid compressing the insulation.

How to insulate the attic air sealing the attic energy saving attic insulation duration. Cover the metal ductwork with closed cell spray foam. That s what happened to the ducts in the lead photo of this article. If necessary switch the wires to reduce the blower to its lowest.

Use metal flex or fiber board ducts that are insulated to code. It was new when the ac was put in 7 years ago. Use a pressure sensitive vapor retarder tape designed for 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.

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. The attic ductwork is flex duct work. Bury the ducts deeply in insulation. Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.

Cover the spray foam with fire retardant spray. Because the simplest and cheapest way to insulate an attic is to add material to the floor. If you want to cover metal ductwork with blown in insulation t hese steps must be followed in this order. 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.

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