Ducts In Attic Insulation

Apply a long strip of foil tape along the seam in the insulation.

Ducts in attic insulation.

If your attic has enough insulation and proper air sealing and your home still feels drafty and cold in the. Other times insulation may be on the outside. 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. 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.

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. But in my last article i also showed you some preliminary results from a research study on buried ducts in a hot humid climate. The insulation levels should meet or exceed the code required r value for attic insulation.

Wrap the insulation around the duct and then pinch the seam closed. 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 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. 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.

If the ducts in your home are in unconditioned space seal and insulate them. Flexible ductwork comes with different insulation r values. The duct insulation should include a vapor barrier cover. Repeat to insulate the remaining ducts.

Test total duct leakage. 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. Mechanically fasten and mastic seal all duct connections. Secure the insulation with short strips of foil tape.

Sometimes the insulation is inside the ductwork. Add additional sealant if necessary. 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. Since burying ducts is simply one of several ways to address the energy waste associated.

Solutions to the attic duct problem. Install loose fill insulation to cover the ducts and the attic floor to meet or exceed the code required r value for attic insulation.