Thermal comfort in office buildings: Two case studies commented

Air conditioning in offices has become a current practice in North Western Europe. The main reasons for that are high internal loads, solar gains and increased comfort expectations. Hence, the move away from the naturally ventilated cellular office increased thermal comfort complaints. The paper presents two cases. In both the results of a comfort enquiry are compared with measurements. The enquiries gave numbers of dissatisfied at a PMV zero that were much higher than the standard PMV/PPD curve does. Measurements instead showed that in one of the two offices only comfort complaints could be expected in summer. But even then, the enquired severity of complaints could not be related to the measured data. Several hypotheses are forwarded to explain the results. Individuals interpret the -3 to +3 scale for thermal sensation differently, which has a direct impact on the number of dissatisfied. The standard curve further-on is a most significant mean of thousands of steady state comfort votes under well-controlled conditions while an on site enquiry involves much smaller numbers of people. These have a clear expectation: an improvement of comfort condition, thanks to the study. For that reason they may exaggerate their complaints when enquired. And finally, an alternative PMV versus PPD curve, published in literature, shows more people complaining at a given PMV than the standard curve forwards. (C) 2008 Elsevier Ltd. All rights reserved.