An experimental study of the human thermal sensation of hot water showering in residential bathrooms

Abstract

Statistics of residential energy consumption show that 20% of the end-use energy is for water heating. As bathing and showering are the biggest consumers of domestic hot water, a truly efficient thermal environmental control for residential bathrooms can optimize energy savings. This study examines the probable relationship between the thermal environment in a bathroom and the thermal sensation of the showering subjects. A total of 31 volunteers (19 males and 12 females) participated in the showering experiments and their subjective thermal responses, including thermal sensation, thermal comfort and thermal acceptability votes, were recorded. The results showed a non-linear trend of thermal sensation vote (TSV) against the operative temperature in the bathroom. An average TSV drop of −0.71 was recorded for an average operative temperature drop of 8.1°C from a neutral operative temperature to=25.7°C with an average shower water temperature of 38.8°C, corresponding to an average drop of TSV=−0.088°C−1. An average increment of TSV=+0.68 was recorded for an increment of t o=+4°C, corresponding to +0.17°C−1. Despite the fact that the female TSV values were more sensitive than the male ones in both the colder and warmer experiments, there were no significant gender differences. This study can be used as a reference to help optimize the thermal environment in bathrooms.