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This study explores the relationship between the perceived performance of specific IEQ factors and occupants’ overall satisfaction with their workspace. In particular we examine the influence of ventilation system type (i.e. Air-Conditioned AC, Mixed-Mode MM, Naturally Ventilated NV) on that relationship. Statistical analyses were conducted on the post-occupancy survey database from the University of California at Berkeley’s Center for Built Environment (CBE) to estimate the relative importance of individual IEQ factors on occupants’ overall satisfaction, depending on whether or not the occupants were satisfied with the IEQ factor in question. Based on these analyses, 15 IEQ factors were classified as Basic Factors, Bonus Factors or Proportional Factors, according to their relationship with overall satisfaction, as described in Kano’s satisfaction model. We found that the classification of some IEQ factors differed for the occupants of AC, MM and NV buildings, suggesting that occupants of buildings with different ventilation types have different expectations, and respond in different ways to various aspects of the indoor environment. A noticeable difference was in thermal environmental conditions: in NV buildings, good thermal conditions were associated with significantly enhanced overall satisfaction (i.e. strong positive impact), but there was little discernible adverse impact, even when thermal performance was deemed to be poor. In AC buildings, on the other hand, thermal conditions were more directly associated with negative overall evaluations of workspace by occupants (i.e. greater negative impact than positive impact). Finally, in MM buildings, thermal conditions exerted both positive and negative impacts of comparable intensities on overall satisfaction.

Despite a paucity of rigorous scientific evidence causally linking Indoor Environmental Quality (IEQ) issues to office occupants’ productivity, there is a widespread belief that such causality exists; excellent or poor IEQ translate into productivity gains or losses respectively. The aim of this study is to better understand relationship between perceived building performance on specific IEQ factors and occupants’ overall satisfaction with their workspace. Kano’s satisfaction model, developed originally in the context of marketing, is adapted and tested for its suitability in the context of building occupants’ satisfaction. Analyses were conducted on the occupant survey database from Center for the Built Environment (CBE) to estimate individual impacts of 15 IEQ factors on occupants’ overall satisfaction, depending on the building’s performance in relation to those IEQ factors. These empirical analyses identified nonlinearitiesbetween some IEQ factors and occupant satisfaction; some IEQ factors had a predominantly negative impact on occupants’ overall satisfaction when the building underperformed. These have been labelled Basic Factors in the Kano Model of satisfaction and include ‘temperature’, ‘noise level’, ‘amount of space’, ‘visual privacy’, ‘adjustability of furniture’, ‘colours & textures’ and ‘workspace cleanliness’. Other IEQ factors had a predominantly linear relationship with overall satisfaction e increments or decrements of equal magnitude in the building’s performance on these factors lead to a broadly similar magnitude of enhancement or diminution of occupants’ overall satisfaction. These were labelled Proportional Factors, and include ‘air quality’, ‘amount of light’, ‘visual comfort’, ‘sound privacy’, ‘ease of interaction’, ‘comfort of furnishing’, ‘building cleanliness’ and ‘building maintenance’.