Ducts In Attic 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.

Ducts in attic insulation.

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. 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. 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.

Sometimes the insulation is inside the ductwork. 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. They found r 8 duct insulation was sufficient to prevent. Since burying ducts is simply one of several ways to address the energy waste associated.

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. Flexible ductwork comes with different insulation r values. If the ducts in your home are in unconditioned space seal and insulate them. If your attic has enough insulation and proper air sealing and your home still feels drafty and cold in the.

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. The duct insulation should include a vapor barrier cover. Other times insulation may be on the outside.

If you re building a new house place ducts in the conditioned space to avoid the energy losses associated with most duct systems. Mechanically fasten and mastic seal all duct connections. 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. Secure the insulation with short strips of foil tape.

Add additional sealant if necessary. Install loose fill insulation to cover the ducts and the attic floor to meet or exceed the code required r value for attic insulation. To install preformed duct insulation start by disconnecting an elbow to expose the end of the duct. The insulation levels should meet or exceed the code required r value for attic insulation.

Figure 1 shows a duct that is encapsulated in spray foam and then partially fully or deeply buried in blown attic insulation. In last week s blog i discussed the practice of burying attic ducts in deep insulation.