Rooftop Membrane Temperature Reductions with Green Roof Technology in South-Central Texas

Abstract

Early green roof cooling and energy reduction research in North America took place in Canada and the northern latitudes of the United States, where green roofs reduced rooftop temperatures by 70% to 90%. Less is known about green roof technology in the southern Untied States; where energy demand for cooling buildings is high, and the urban heat island effect is more pronounced. This paper reports early findings for rooftop membrane temperature reductions from 11.6-cm-deep modular green roof trays, typical of large-scaled, low-maintenance applications. Measurements observed during May, 2010 reveal that temperatures below the modular planted green roof units were 82% to 91.6% cooler compared to the surface temperatures of the control roof membrane. These findings on low-input modular green roof trays reinforce other research findings that indicate green roof technology can dramatically reduce and modify temperatures on roof deck surfaces during peak energy demand periods in hot sunny climates.