Rehva Guide No 6 - Indoor Climate and Productivity in Offices - states as its main purpose to establish quantitative relationships of indoor environmental aspects with performance and sickness absenteeism. The following relationships were established: temperature with performance, ventilation with performance, perceived indoor air quality with performance and ventilation with sickness absenteeism. The purpose of this paper is to establish what in practice are, or probably are, the most effective measures to increase performance and decrease absenteeism, given the total of the presently available evidence. We argue that robust measures, like avoidance of indoor air pollution sources, minimizing external and internal heat load, thermal effective building mass, cellular office layout with shallow plan depth, occupant control of temperature, operable windows and providing for adaptive thermal comfort are more effective in increasing performance and reducing absenteeism than less robust measures like diluting indoor air pollution through increased ventilation, controlling temperature through mechanical cooling and open plan workroom layout combined with deep plan depth..

Results from 10 Dutch mitigation studies (approximately 700 respondents in total) include, apart from an elaborate list of questions about health and comfort responses and building characteristics, data about self reported productivity. The main results are an analysis of the relation of productivity data with health and comfort responses and building characteristics. The general validity of self reported productivity data is discussed on the basis of these results and a literature review. Analysis shows that both negative occupant responses on health and comfort and building characteristics that indicate pollution sources correlate with self reported productivity loss.

Building-related symptoms occur more often in office buildings with air conditioning and sealed windows. Avoiding construction of such buildings, therefore, seems advisable. Nevertheless, many new Dutch buildings are air conditioned and sealed. This study consists of the arguments that have been made for continuing to build air-conditioned and sealed buildings and a validity test of those arguments. Some arguments (e.g., outside noise, wind) rightly support the need for mechanical air supply in certain situations. But even then, operable windows with smart design have proved themselves to be applicable and effective. Some arguments in favor of air conditioning and sealed windows appeared to be invalid (e.g., preventing dry air). High heat loads seemed to be the most sound argument in favor of air conditioning. However, a calculation showed that, given the Dutch climate, high indoor temperatures can be avoided without cooling when certain design criteria concerning building characteristics are met. Despite common beliefs, it is quite possible to avoid sealed windows and air conditioning in Dutch office buildings. Note that several factors analyzed in this study are based on the climatic conditions of the Netherlands and may not be valid in other climates.