Heat and Humidity Effects on Human Comfort and Performance – Physiology Meets Building Science

Understanding how humans react to elevated temperature and humidity is highly relevant for conditioning buildings, especially work environments. Humans and air-conditioned buildings also have much in common in how they exchange thermal energy and maintain temperature. At low activity levels and moderate air temperatures, heat loss is mainly sensible (convection and radiation), but at higher temperatures or exertion levels, evaporative cooling through sweating becomes crucial. Because evaporation depends on absolute humidity, humidity control is essential in warm environments. Humans differ markedly in their preferences and especially capacities to tolerate hot environments, so a basic understanding of these differences is valuable.