The Future of Thermal Comfort in a Warming World

Building cooling energy demand in the warmer climates of the world is increasing due to population growth and built environment expansion. Currently, cooling energy demand is increasing at a rate of 8% per annum, and this is projected to increase more rapidly with global warming. However, much of this demand is driven by unsustainably low indoor building temperature set points, that are also fundamentally seen as undesirable by most building occupants. In this study, we examine the effect of this “overcooling” in a changing climate using data from Qatar as a case study of a location with high average and peak external temperatures. Field data from 4 buildings in public and private settings demonstrate that cold discomfort is about 20 percentage points higher than warm discomfort due to excessive air-conditioning. Computer energy simulations using morphed future weather data and the extrapolated effect of observed low internal building temperatures, demonstrate that overcooling exacerbates the effect of a warming world by 16 percentage points. In other words, the use of more climatically appropriate thermal comfort standards that avoid unnecessary overcooling could reduce 28% of global carbon emissions in a future warmed world. As anecdotal evidence of excessive cooling in other warm climates demonstrates that the effects of overcooling are true, the reduction of building overcooling results in a greater achievement of thermal comfort, a decrease in cooling energy consumption, and a decline in carbon emissions across the warm climates of the world.