Statistical analysis of unsolicited thermal sensation complaints in commercial buildings.

Unsolicited complaints from 23,500 occupants in 690 commercial buildings were examined with regard to absolute and relative frequency of complaints, temperatures at which thermal sensation complaints (too hot or too cold) occurred, and response times and actions. The analysis shows that thermal sensation complaints are the single most common complaint of any type and that they are the overwhelming majority of environmental complaints. The analysis indicates that thermal sensation complaints are mostly the result of poor control performance and HVAC system faults rather than inter-individual differences in preferred temperatures. The analysis also shows that the "neutral" temperature in summer is greater than in winter, and the difference between summer and winter "neutral" temperatures is smaller than the difference between the midpoints of the summer and winter ASHRA.E comfort zones. On average, women complain that it is cold at a higher temperature than men, and the temperature at which men complain that it is hot is more variable than for women. Analysis of response times and actions provides information that may be useful for designing a dispatching policy, and it also demonstrates that there is potential to reduce the labor cost of HVAC maintenance by 20% by reducing the frequency of thermal sensation complaints.