Insulating Hvac Ducts In Attic

Use metal flex or fiber board ducts that are insulated to code.

Insulating hvac ducts in attic.

When hvac ducts are installed in a vented attic in a dry climate bury the ducts in attic insulation to protect them from temperature extremes in the unconditioned attic space. Seal the leaks with mastic or mastic tape we follow a highly precise seal and test protocol that identifies all leaky areas and results in 4 duct leakage or less. In this video this old house plumbing and heating expert richard trethewey helps a homeowner insulate his ductwork. Make sure the foil surface of the insulation is free of dust before applying the tape.

Use the type of metallic foil duct tape recommended by the insulation manufacturer to seal and hold the insulation in place. Install ductwork so that it is in direct contact with i e laying on the ceiling and or truss lower cords. In addition to making the unit hard to get to for service high attic heat can trigger the. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards that specify an r value of 8.

If necessary switch the wires to reduce the blower to its lowest speed. Looking at the cooling side only the additional load would be. According to rightsuite the software we use the supply ducts have about 560 square feet of surface area and the return ducts 101 square feet. How to insulate your central air heating ducts.

Let s look for constantly improving methods through sharing. 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. Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. Check the speed of the blower motor on the furnace.

Measure and cut your duct insulation a little large to allow overlap at every seam both lengthwise and on the ends. Before beginning read the product instructions and follow wherever they deviate from general duct insulation guidelines. R 8 duct insulation 5 227 btu hour. Dirty air will still enter your ductwork through the leaks even after you add insulation.

If you decide to insulate your old ducts just make sure you or your contractor follows this order of operations. Wrap fiberglass duct insulation around the ducts and tape the seams together. Wrap the insulation around the duct allowing the beginning edge to ride up slightly over the previous piece. The duct insulation should include a vapor barrier cover.

Putting a furnace in an attic is not ideal but will happen. All the ducts are in the attic. 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.

Put it in an attic full of blown insulation and you re forcing it to work harder to vent its heat.