Insulating Hvac Ducts In Attic

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.

Insulating hvac ducts in attic. Before beginning read the product instructions and follow wherever they deviate from general duct insulation guidelines. In this video this old house plumbing and heating expert richard trethewey helps a homeowner insulate his ductwork. If you decide to insulate your old ducts just make sure you or your contractor follows this order of operations. Inspect the span of ductwork to be insulated.

Dirty air will still enter your ductwork through the leaks even after you add insulation. Check the speed of the blower motor on the furnace. Wrap the insulation around the duct allowing the beginning edge to ride up slightly over the previous piece. Put it in an attic full of blown insulation and you re forcing it to work harder to vent its heat.

If necessary switch the wires to reduce the blower to its lowest speed. 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 your central air heating ducts. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards that specify an r value of 8.

Measure and cut your duct insulation a little large to allow overlap at every seam both lengthwise and on the ends. 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 addition to making the unit hard to get to for service high attic heat can trigger the.

Press a continuous strip of foil tape to all longitudinal seams along straight runs of duct. Make sure the foil surface of the insulation is free of dust before applying the tape. Insulating hvac ductwork when insulating hvac ductwork use a foil faced fiberglass insulation with an r 6 or higher r value. Use metal flex or fiber board ducts that are insulated to code.

Look for signs of air leaks at seams or joints such. Wrap fiberglass duct insulation around the ducts and tape the seams together.