Personal control over the workspace

The built environment researcher Stefano Schiavon exposed 56 tropically acclimatised people in ordinary Singaporean office clothing to five conditions of 90 minutes each: 23, 26 and 29 °C, and the last two both with and without a fan the occupant could control. Relative humidity was held at 60%. With the fan available, thermal comfort, perceived air quality and sick building syndrome symptoms at 26 and 29 °C were equal to or better than at the common set point of 23. Task speed peaked at 26 °C. At 29 °C the fan partially offset the effect of the heat rather than removing it. A building held at 26 °C instead of 23 spends less on cooling, and Schiavon’s participants were as comfortable there as at 23 provided they controlled the fan.

The architecture researcher Minyoung Kwon ran field studies in five Dutch office buildings, asking occupants online how satisfied they were and setting that against how much they could actually adjust. Higher controllability went with more satisfaction with thermal and visual comfort, at a statistically reliable association. The differences appeared between having no control at all and having some, which the paper reads as a psychological effect on top of the physical one. The abstract does not report how many occupants answered.

The building researcher Toby Cheung found the same thing as a complaint. Among 666 occupants of seven Green Mark certified air-conditioned buildings in Singapore, personal control was the second-worst rated of 18 parameters, with 32% dissatisfied, behind sound privacy at 42% and ahead of temperature at 30.

The architecture researcher Madhavi Indraganti and Isaac Meir approached it from opposite ends of the same question. In seven Doha office buildings, occupants were highly satisfied with most environmental parameters and unsatisfied with acoustics, and access to operable windows and thermostats improved their satisfaction; people in private offices were more satisfied than others. Meir evaluated a courthouse in a hot arid climate built with windows that do not open, and found a strong association between satisfaction, ventilation and a sense of wellbeing at work. Asked what they would give up for windows that open, the courthouse workers named future salary rises. The abstract available here reports no occupant count.

The engineering researcher Yannick Sutter recorded the blinds in eight offices every 15 minutes for 30 weeks, alongside the illuminance at the window and at the screen, the room temperature, whether anyone was present and the state of the artificial lighting; seven further offices with manual fabric blinds were photographed by webcam on the same interval. Each person used the shading consistently in their own way. The paper is careful about what follows from that, and says general conclusions on blind usage were difficult to draw. Reinhart and Voss monitored ten daylit German offices from March to December 2000 and found the same individual consistency, with everyone lowering the blinds to keep out direct sunlight above 50 watts per square metre.

Schiavon tested 56 people under controlled conditions and Cheung surveyed 666. Five Dutch buildings in Kwon, seven Doha buildings in Indraganti and one courthouse in Meir all arrive without occupant numbers. Sutter watched fifteen offices for 30 weeks and Reinhart and Voss ten for nine months. Neither varied anything, so both describe how each person used the blinds.