Internal Microclimate Resulting From Ventilated Attics in Hot and Humid Regions

Abstract

Ventilated spaces in the built environment create unique and beneficial microclimates. While the current trends in building physics suggest sealing attics and crawlspaces, comprehensive research still supports the benefits of the ventilated microclimate. Data collected at the University of Florida Energy Park show the attic environment of asphalt shingled roofs to be typically hotter than the outdoor conditions, but when properly ventilated sustains a much lower relative humidity. The hot, humid regions of the United States can utilize this internally convective, exchanging air mass to provide stable moisture levels within attic spaces. Positioning the buildings primary boundary at the ceiling deck allows for utilization of this buffer climate to minimize moisture trapping in insulation and maximize the insulation’s thermal benefits. This investigation concludes the conditions in a ventilated attic are stable through seasonal changes and promotes cost effective, energy efficient climate control of unconditioned spaces in hot, humid regions.