How To Insulate Heating Ducts In Attic

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.

How to insulate heating ducts in attic.

Measure each run of exposed duct in an attic basement or under a subfloor. How to insulate your central air heating ducts 1. The rigid insulation was saturated from condensation. 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.

Look for signs of air leaks at seams or joints such as streams of dust. Use a paintbrush to apply duct mastic to the joints where an elbow connects to a duct. If using this technique in a humid or marine climate the ducts must be encapsulated with spray foam before installing the blown insulation. Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.

For an added layer of protection you can apply duct mastic to the tape and duct. Install loose fill insulation to cover the ducts and the attic floor to meet or exceed the code required r value for attic insulation. Bury the ducts deeply in insulation. They may have an adhesive strip to make the installation a little easier.

Come in pre measured lengths. That s what happened to the ducts in the lead photo of this article. Don t use standard cloth duct tape on hvac ductwork since the adhesive won t hold up to extreme temperatures. 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.

To install sleeves you must either disassemble the ductwork and slide it on before reassembling the ducts or as many homeowners find themselves doing slit it and wrap it around like the blanket style material. In the end it s probably best to buy the blanket insulation. Measure the size of all square rectangular or circular ducts. How to insulate the attic air sealing the attic energy saving attic insulation duration.

If necessary switch the wires to reduce the blower to its lowest speed. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards. Check the speed of the blower motor on the furnace. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct.

Energy saver dealers 204 202 views. Inspect the span of ductwork to be insulated. Obtain foil face fiberglass insulation based on the sizes.