Temperature and Office Work Performance
The influence of indoor air temperatures on objective (measured) work performance in offices has been assessed experimentally in numerous studies, primarily in call centers and laboratory settings representative of real offices. In call center studies, the time required to interact with clients via the telephone and perform related information processing via a computer was used as the performance outcome. The laboratory studies had participants perform tasks representative of office work, such as proof-reading, text typing, and simple arithmetic operations. Speed and accuracy in these simulated work tasks was measured and used to indicate work performance. A few additional studies used vigilance tests to measure ability to concentrate. Most of the studies experimentally manipulated temperatures while holding other factors constant to investigate the influence of temperature on performance, although one call center study relied on natural changes in air temperature.
Recently, a formal statistical analysis of 24 of these studies was completed [1] to assess the average relationship between temperature and performance of work. The authors primarily analyzed office studies and laboratory studies that simulated office work, although three of 24 studies were performed in classrooms. Their analyses are the source of Figure 1 illustrating a best estimate of how office work performance varies with temperature. The graph in Figure 1 shows that performance is maximized when the air temperature is approximately 71 °F. As the indoor air temperature rises above or falls below 71 °F, work performance decreases. The equation for the curve in Figure 1, resulting from the statistical analysis, is
where
P is productivity relative to the maximum value
TF is room temperature, °F.
The equation should not be used for temperatures below 59 °F or above 89 °F.
Figure 1. The relationship between office work performance and indoor temperature based on a statistical analysis of reported data. The line from a modeled statistical fit to data from 24 studies. The shaded areas in the figure represent the regions where there is a high level of statistical confidence about the performance decrements, i.e., where statistical analyses indicate that decrements in performance in these regions have less than a 10% probability of being the result of chance.
Figure 1 and equation 1 are based on 24 studies. These studies involved only call center work and work tasks for which speed and accuracy could be readily quantified. While the predicted performance changes with temperature are statistically significant over much of the range shown, there remains a high uncertainty about the magnitude of performance changes one should expect in actual practice. It is possible that the effects of temperature on work performance may vary substantially with type of work, climate, clothing level, and with building features that affect indoor environmental quality.