How To Insulate Flex Ductwork In Attic

Applying spray foam insulation to the outside of the duct.

How to insulate flex ductwork in attic. Consider adding more insulation as ductwork is farther from the furnace. I found instead a vintage 3 ton ac unit with 1 rigid insulation taped all over it and insulated flex duct snaking all over the poorly insulated attic. The cost and effort to add more insulation is minimal. The duct insulation should include a vapor barrier cover.

Wrapping the duct in a foil faced blanket. Cover the metal ductwork with closed cell spray foam. Heaping insulation over the ducts is fine in dry climates but can cause condensation on the duct insulation jacket in humid climates. If it s uninsulated you should insulated it to at least r 4 to r 8 for dfw.

How to insulate the attic air sealing the attic energy saving attic insulation duration. The two most common ways to insulate ductwork are. Use a pressure sensitive vapor retarder tape designed for ductwork. Energy saver dealers 204 202 views.

If you need help deciding which type of insulation you need set up an energy consultation. Use metal flex or fiber board ducts that are insulated to code. Start saving money today. If you want to cover metal ductwork with blown in insulation t hese steps must be followed in this order.

The flex ducts were literally filled shut with ice in the low spots compressing the scant insulation layer beneath them. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. The rigid insulation was saturated from condensation. By spraying closed cell foam on the ducts before burying them in attic insulation you prevent the condensation problem.

The first thing you want to do is take either air duct sealant or mastic and spread it around the take off. 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. Mechanically fasten and mastic seal all duct connections. Mastic comes in a bucket air duct sealant comes in a tube they re basically the same thing.

That s what happened to the ducts in the lead photo of this article. You re throwing money out the window. Avoid compressing the insulation. If your rigid metal ductwork has any insulation it may already have enough.

The doe s building america program recommends beds buried encapsulated ducts. 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. Stop wasting money and energy with a leaking duct system. Bury the ducts deeply in insulation.

The foam provides a vapor barrier so the 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. Spread it around with either your fingers or a disposable chip brush or disposable paint brush.