Ducts In Attic Insulation

Test total duct leakage.

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. 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. 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.

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. Figure 1 shows a duct that is encapsulated in spray foam and then partially fully or deeply buried in blown attic insulation. Solutions to the attic duct problem.

But in my last article i also showed you some preliminary results from a research study on buried ducts in a hot humid climate. 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. Apply a long strip of foil tape along the seam in the insulation. Add additional sealant if necessary.

They found r 8 duct insulation was sufficient to prevent. In last week s blog i discussed the practice of burying attic ducts in deep 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. Sometimes the insulation is inside the ductwork.

The insulation levels should meet or exceed the code required r value for attic insulation. Flexible ductwork comes with different insulation r values. 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. The duct insulation should include a vapor barrier cover.

Since burying ducts is simply one of several ways to address the energy waste associated. Secure the insulation with short strips of foil tape. 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. If your attic has enough insulation and proper air sealing and your home still feels drafty and cold in the.

If the ducts in your home are in unconditioned space seal and insulate them. To install preformed duct insulation start by disconnecting an elbow to expose the end of the duct.