How To Insulate Duct In Attic

How to insulate your attic duct system step by step with video instructions assess current state of attic insulation.

How to insulate duct in attic.

See recommendations for accomplishing this at the building america solution center. Insulate and air seal to pull the attic inside the building. If necessary switch the wires to reduce the blower to its lowest. Bury the ducts deeply in insulation.

Look for signs of air leaks at seams or joints such as streams of dust. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. 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. Inspect the span of ductwork to be insulated.

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. Make sure the foil surface of the insulation is free of dust before applying the tape. How to insulate the attic air sealing the attic energy saving attic insulation duration. The duct work is the backbone of air exchange and ventilation.

That s what happened to the ducts in the lead photo of this article. Insulation itself keeps warm air in and prevents cold air from infiltrating. When insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value. How to insulate your central air heating ducts 1.

The next best option is to encapsulate the ducts. Measure and cut your duct insulation a little large to allow overlap at every seam both lengthwise and on the ends. This could and should have been done in the first place but now you have another chance to make it right. If using this technique in a humid or marine climate the ducts must be encapsulated with spray foam before installing the blown insulation.

Check the speed of the blower motor on the furnace. Install loose fill insulation to cover the ducts and the attic floor to meet or exceed the code required r value for attic insulation. Sure up leaky duct joints. Use a paintbrush to apply duct mastic to the joints where an elbow.

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. Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place.