Ducts In Attic Insulation

Since burying ducts is simply one of several ways to address the energy waste associated.

Ducts in attic insulation. If your attic has enough insulation and proper air sealing and your home still feels drafty and cold in the. The insulation levels should meet or exceed the code required r value for attic insulation. Secure the insulation with short strips of foil tape. Apply a long strip of foil tape along the seam in the insulation.

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. But in my last article i also showed you some preliminary results from a research study on buried ducts in a hot humid climate. Solutions to the attic duct problem. Mechanically fasten and mastic seal all duct connections.

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. Because the moving air is in the ductwork for only a short period of time it does not need the insulation r value the attic floor requires. 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. 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.

Test total duct leakage. Install loose fill insulation to cover the ducts and the attic floor to meet or exceed the code required r value for attic insulation. Other times insulation may be on the outside. The duct insulation should include a vapor barrier cover.

Repeat to insulate the remaining ducts. Figure 1 shows a duct that is encapsulated in spray foam and then partially fully or deeply buried in blown attic insulation. They found r 8 duct insulation was sufficient to prevent. Wrap the insulation around the duct and then pinch the seam closed.

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. To install preformed duct insulation start by disconnecting an elbow to expose the end of the duct. 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. In last week s blog i discussed the practice of burying attic ducts in deep insulation.

Sometimes the insulation is inside the ductwork. If you re building a new house place ducts in the conditioned space to avoid the energy losses associated with most duct systems.