A preliminary evaluation of two strategies for raising indoor air temperature setpoints in office buildings

Mechanically ventilated office buildings are designed to provide productive work conditions for their occupants. This article presents findings from an attempt to improve occupant comfort and reduce energy use at 33 such buildings by adjusting internal air temperature setpoints to account for seasonal variations in ambient climatic conditions. Two approaches were adopted: a static control strategy (i.e. raising temperatures 18C higher than normal over summer); and a dynamic approach (i.e. adjusting temperatures in direct response to variations in ambient conditions). It was found that occupant comfort was adversely affected in both trials, while the 18C static setpoint increase was associated with a 6% reduction in daily heating, ventilation and air-conditioning energy use, slightly less than the 6.3% reduction where the dynamic approach was adopted. These findings, together with a range of implementation challenges that surfaced during the trial, have significant implications for the implementation of adaptive comfort control strategies in commercial buildings.