The Impact of Cool Roofs in Different Climatic Regions: A Quantitative Empirical Analysis

Abstract

This research investigated regional climate differences and weather impacts on the effectiveness of cool roofs. In most US climate zones, cool roofs can reduce energy consumption because they reflect more sunlight and heat than standard roofs. Since temperatures are expected to increase in many regions, cool roofs may offer greater energy and cost savings than currently estimated. Energy consumption by Department of Energy (DOE) Research Laboratory buildings across the US with cool and standard roofs were assessed using metered energy datasets collected from 2003-2013. Statistical tests were conducted to compare differences in energy consumption of buildings between cool and standard roofs at sites in different climatic regions. In order to better understand the effectiveness of cool roof technologies in a future that is expected to become increasingly warmer, data collected from weather stations near each DOE site were used to interpret the potential influences of weather patterns on cool roof energy savings. This research confirmed that cool roofs do reduce energy consumption, especially at sites with warmer summers and milder winters. Regression analyses of energy consumption and temperature data were conducted to identify associations between air temperatures and heating and cooling degree-days with seasonal energy consumption. While the energy consumption of buildings with cool roofs was generally less than buildings with standard roofs, the differences in energy consumption varied depending on building use and building size.