This paper presents the main findings of ASHRAE research project RP-921, a field study of occupant comfort and office thermal environment in 22 air-conditioned office buildings in Kalgoorlie-Boulder, Western Australia, a location characterized by a hot and arid climate. A total of 935 subjects provided 1,229 sets of data for winter and summer, each accompanied by a full set of indoor climatic measurements with laboratory-grade instrumentation. Clothing insulation estimates for seated subjects (0.5 clo in summer and 0.7 in winter) were supplemented by the incremental effect of chairs (0.15 clo). Thermal neutrality, according to responses on the ASHRAE seven-point sensation scale, occurred at 20.3°C in winter and at 23.3°C in summer. Preferred temperature, defined as a minimum of subjects requesting temperature change, was 22.2°C for both seasons. Nearly 65% of the indoor measurements fell within the ANSI/ASHRAE Standard 55a-1992 summer comfort zone and 85% in the winter. Over 85% of the occupants considered their thermal conditions acceptable. Subjects who expressed a below-average level of job satisfaction on a 15-question index were 50% more likely to express dissatisfaction with their thermal environment than subjects with above-average job satisfaction.

Units: SI