As unvented attics have become a more common design feature implemented by Building America partners in hot-dry climates of the United States, more attention has been focused on how this approach affects heating and cooling energy consumption. By eliminating the ridge and eave vents that circulate outside air through the attic in most new houses and by moving the insulation from the attic floor to the underside of the roof, an unvented attic becomes a semiconditioned space, creating a more benign environment for space conditioning ducts. An energy trade-off is made, however, because the additional surface area (and perhaps reduced insulation thickness) increases the building loss coefficient. Other advantages and disadvantages, unrelated to energy, must also be considered. This paper addresses the energy-related effects of unvented attics in hot-dry climates based on field testing and analysis conducted by the National Renewable Energy Laboratory.
Thermal Performance of Unvented Attics in Hot-Dry Climates: Results from Building America
Contributed by the Solar Energy Division of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS for publication in the ASME JOURNAL OF SOLAR ENERGY ENGINEERING. Manuscript received by the ASME Solar Energy Division, May 2003; final revision, August 2003. Associate Editor: M. Krarti.
Hendron , R., Farrar-Nagy , S., Anderson, R., Reeves, P., and Hancock, E. (May 4, 2004). "Thermal Performance of Unvented Attics in Hot-Dry Climates: Results from Building America ." ASME. J. Sol. Energy Eng. May 2004; 126(2): 732–737. https://doi.org/10.1115/1.1687795
Download citation file: