Effect of reduced summer indoor temperature on symptoms, perceived work environment and productivity in office work

Abstract

The effects of reduced summer indoor temperature, through renovation of an HVAC system, on symptoms, perceived environment and productivity in an office building are investigated. Measurements of indoor parameters, perceived environment and productivity were conducted over two successive summers. Two floors of the office building were renovated during the wintertime. The renovation mainly consisted of cooling the supply air, installation of cooling ceilings in about half of the office rooms, and distributing supply air to all office rooms. An indoor air questionnaire assessing current symptom intensity, including questions on self-estimated work efficiency, was presented to employees on five days each summer. The measurements taken during the summer before the renovation showed that indoor temperatures rose above thermal comfort levels (maximum temperature 31.4°C). When the temperature rose above 25°C, neurobehavioural symptoms and the percentage of those dissatisfied with the indoor air quality increased, and self-estimated work efficiency decreased statistically significantly. After the renovation, thermal indoor comfort was achieved, and the percentage dissatisfied with the temperature and indoor air quality remained at a low level, i.e. 2–4 per cent. Objective productivity measurements conducted with a few employees performing solo work showed a 4.4 per cent improvement of work efficiency in the summertime.