Indoor climate and moisture durability performances of houses with unvented attic roof constructions in a mixed-humid climate.
A sealed or unvented attic is an energy-efficient envelope component that can reduce the amount of energy a house consumes for space conditioning if the air handler and/or ducts are located in the attic. The attic is typically sealed by using spray foam on the underside of the roof deck and covering the soffit, ridge and gable vents to minimize air leakage from the attic to the outside. This approach can save up to 10% in space-conditioning energy when ducts are located in the attic (DOE 2013). Past research done by ORNL and Florida Solar Energy Center suggests that in more hot, humid climates, an unvented attic could potentially create a more humid, uncomfortable living environment than a vented attic (Colon 2011, Boudreaux, Pallin et al. 2013). Research showed that controlling the higher indoor humidity could reduce the energy savings from the sealed, unvented attic, which in turn would decrease the energy savings payback. Research also showed that the roof assembly (5.5 inches of open-cell foam, 1inch of closed-cell foam, OSB, felt paper, and asphalt shingles) stored moisture, thus acting as a moisture buffer. During the fall and winter, the roof assembly stored moisture and during the spring and summermore »
- Publication Date:
- OSTI Identifier:
- Report Number(s):
- DOE Contract Number:
- Resource Type:
- Technical Report
- Research Org:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Building Technologies Research and Integration Center (BTRIC)
- Sponsoring Org:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Country of Publication:
- United States
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