Effect of Overcooling on Productivity Evaluated by the Long Term Field Study

A long-term field study was conducted in an office for seven months to clarify the effect of thermal environment on productivity. Seven male software programmers participated as subjects. They answered the questionnaires on their personal computer including thermal sensation votes, complaints about their working environment, fatigue, vitality, mental workload and self estimated productivity every workday. The numbers of keystrokes were automatically recorded during the operation of their computers. Advanced Trail Marking Test (ATMT) was also conducted as the estimation of performance. Under lower temperature, the percentage of dissatisfied about Low temperature and Draft were higher and the vitality level was lower. The decrement in the total number of keystrokes of one day was 7.8% and that in the numbers of reaction per second of ATMT was 2.6% as temperatures dropped by 1.0C below thermally neutral temperature. The result showed that overcooling brought the decrement of performance in the office.