Ducts In Attic Insulation

Add additional sealant if necessary.

Ducts in attic insulation.

If you re building a new house place ducts in the conditioned space to avoid the energy losses associated with most duct systems. They found r 8 duct insulation was sufficient to prevent. The insulation levels should meet or exceed the code required r value for attic insulation. Purchase duct wrap insulation that complies with the 2009 international energy conservation code iecc standards that specify an r value of 8 for attic ducts and 6 for ducts located anywhere else.

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. If the ducts in your home are in unconditioned space seal and insulate them. Since burying ducts is simply one of several ways to address the energy waste associated. Secure the insulation with short strips of foil tape.

The duct insulation should include a vapor barrier cover. 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. Wrap the insulation around the duct and then pinch the seam closed. Apply a long strip of foil tape along the seam in the insulation.

Other times insulation may be on the outside. But in my last article i also showed you some preliminary results from a research study on buried ducts in a hot humid climate. Flexible ductwork comes with different insulation r values. Mechanically fasten and mastic seal all duct connections.

Yes when you bury ducts in attic insulation in a humid climate you increase the risk of water vapor condensation on the jacket of the duct insulation. In last week s blog i discussed the practice of burying attic ducts in deep insulation. Figure 1 shows a duct that is encapsulated in spray foam and then partially fully or deeply buried in blown attic insulation. Sometimes the insulation is inside the ductwork.

To install preformed duct insulation start by disconnecting an elbow to expose the end of the duct. In this case the temperature gradient between supply air and the ceiling can be such that the duct surface could be cooler than the local dew point. In a vented attic this can happen when the duct is in close proximity to conditioned space i e the ceiling and also thermally isolated from the hot attic beneath the ceiling insulation. Test total duct leakage.

Solutions to the attic duct problem. Repeat to insulate the remaining ducts.