Occupants' Preferences and Satisfaction with the Visual Environment in Perimeter Zone Offices: A Field Study in a Building with Advanced Technology (ST-16-C013)

As a result of architectural trends, technological advances and increasing focus on energy efficiency, buildings with high performance envelope and HVAC systems, large window-to-wall ratio, motorized window shades, smart lighting controls and Building Automation Systems (BAS) have found their way into the market. With a focus on this building type and dynamic environments such as offices in perimeter zones, this paper presents results of a long-term field study with a large number of human test-subjects, aiming to advance our understanding of (a) occupants’ interactions with shading and electric lighting control systems; and (b) their preferences and satisfaction with the visual environment.

To investigate the impact of  environmental control on occupants’ comfort, satisfaction level and subjective productivity, four identical side-by-side offices with different control setups and interfaces, ranging from fully automated to fully manual and from low-level of accessibility (wall switches) to high-level of accessibility (remote controllers or modular web interfaces) were selected for the purpose of this study. The experimental study includes monitoring of physical variables, actuation and operating status of building systems and online surveys of occupants’ perception of environmental variables as well as their personal characteristics and attributes.

Compared to previous studies conducted in buildings with non-motorized blinds and artificial lights without dimming options, our results show substantial differences in dynamics and frequency of human-shading and –electric lighting interactions for buildings equipped with this advanced technology. Moreover, it was found that comfort with amount of light and visual conditions, satisfaction with window view, and subjective productivity are all maximized in offices with manual control setups and occupants are comfortable with a wide range of indoor illuminance when they have control over their environment. These results also demonstrate occupants’ strong preference for customized indoor climate and the outcomes support the development of personalized controls, which will be discussed in the paper.