How To Insulate Ductwork In Attic

But what about the parts behind the walls and in the ceiling.

How to insulate ductwork in attic. Energy saver dealers 204 202 views. Use metal flex or fiber board ducts that are insulated to code. How to insulate the attic air sealing the attic energy saving attic insulation duration. I called out the original hvac company and they took a look and said they saw no water.

Tape any punctures in the insulation s vapor barrier to prevent leaks. Avoid compressing the insulation. Mechanically fasten and mastic seal all duct connections. 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.

Cover the metal ductwork with closed cell spray foam. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. Use a pressure sensitive vapor retarder tape designed for ductwork. Bury the ducts deeply in insulation.

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. If necessary switch the wires to reduce the blower to its lowest speed. 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.

That s what happened to the ducts in the lead photo of this article. 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. The foam provides a vapor barrier so the ductwork won t sweat. Because the simplest and cheapest way to insulate an attic is to add material to the floor.

The attic and walls are one of the most important areas to insulate in any space. 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. Cover the spray foam with fire retardant spray. 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. It was new when the ac was put in 7 years ago. Plan to pull up the flooring and layer new insulation on top of the old. Use a paintbrush to apply duct mastic to the joints where an elbow connects to a duct.

If you want to cover metal ductwork with blown in insulation t hese steps must be followed in this order.