Effective ventilation in offices - the occupant's perspective.

Air quality and draught avoidance are fairly important to office staff; consequently, the occupant's perspective should be taken into account when assessing the relative merits of different methods of ventilation in office buildings. Environmental comfort ratings and a variety of other judgements were collected in interviews with 169 staff in two air-conditioned and three naturally ventilated office buildings. Comparison of the two building types showed that air conditions were judged to be less satisfactory in the air-conditioned buildings, and that these buildings also had a higher rate of reported 'building sickness' symptoms. However, the differences, although statistically significant, were small in magnitude. Furthermore, while a quarter of all staff interviewed in the air-conditioned buildings made unfavourable comments about the air-conditioning, evidence is reported which suggests that it is the absence of openable windows which is the basis of people's negative attitudes, rather than beliefs about unsatisfactory air quality. One building had airconditioning designed to provide localised control in the form of supply outlets which could be shut off when air was not required. This design, however, was associated with the lowest recorded satisfaction with air conditions, primarily because the conditioned air was experienced as a cold draught.