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ABSTRACT
Indoor temperature is one of the fundamental characteristics of the indoor environment. It can be controlled with a degree of accuracy dependent on the building and its HVAC system. The purpose of this study was to evaluate the potential benefits of improved temperature control and apply the information to a cost-benefit analysis. The indoor temperature affects several human responses, including thermal comfort, perceived air quality, symptoms of sick building syndrome, and performance at work. In this study, we focused on the effects of temperature on performance at work. We collected and analyzed the literature that related performance at work to temperature. The results of multiple studies are relatively consistent, showing an average relationship of a 2% decrement in work performance per °C (1.1% per °F) when the temperature is above 25°C (77°F). Fewer data were available on performance in low temperatures. However, studies show a strong effect on manual tasks with temperatures below thermal neutrality as soon as hand temperature decreases due to control of the flow of blood. When the estimated productivity decrement from raised temperatures was applied to data from a study of nighttime ventilative cooling, the estimated value of productivity improvements were 32 to 120 times greater than the cost of energy to run fans during the night.
INTRODUCTION
In many commercial buildings, thermal conditions are not controlled well, due to insufficient cooling or heating capacity, high internal or external loads, large thermal zones, improper control-system design or operation, and other factors. Thermal conditions inside buildings vary considerably, both with time (e.g., as outdoor conditions change) and spatially. While the effects of temperature on comfort are broadly recognized, the effects on worker productivity have received much less attention.
For example, in a large US study, 50% of the subjects preferred a change in their thermal state, 38% of subjects in winter were dissatisfied with thermal conditions, and almost 50% of thermal conditions during summer were outside the thermal comfort zone (Schiller et al. 1988). Federspiel (2001 ) reported that, in a data set that was collected from 575 buildings in the US, 18.4% of complaints were classified as indoor environmental. Seventy-seven percent of indoor-environmental complaints were about conditions perceived as too hot or too cold. He showed that the rate...