Building energy certification versus user satisfaction with the indoor environment: Findings from a multi-site post-occupancy evaluation (POE) in Switzerland

Voluntary green-rating systems exist in different forms worldwide to certify the sustainability of residential and commercial buildings and help national policies promote energy-efficient design practices. Despite the general assumption that sustainable buildings also provide high comfort and healthy conditions, existing studies on green-rated buildings led to controversial conclusions in this regard. This paper aims to report the results of a post-occupancy evaluation (POE) conducted on four Swiss green buildings certified with the Minergie label to analyse their ability in providing comfort to their occupants. The POE protocol included winter and summer environmental monitoring campaigns (long-term and instantaneous measurements) as well as extensive and point-in-time comfort surveys. From the study it was found that, although the observed environmental factors were most of the time complying with the norm prescriptions, the indoor conditions were never attaining the commonly used 80% satisfaction threshold by the users. Temperature and air quality appeared, in particular, as the most critical factors, with satisfaction rates never greater than 50% in three out of the four case studies. Design factors related to the personal control on the indoor environment as well as personal factors like gender, climate of origin and duration of residence in the country were also found to have an impact in the comfort rating. Professionals involved in the design and management of these buildings all agreed that feedback of this kind from building in use could help inform the design and operational process and move towards more effective green building certification systems and regulations.