Summer-time performance of Finnish housing: POE of five apartments

Purpose Despite the increased retrofitting of Finnish residential buildings, there are limited post-retrofit studies on the actual measured indoor environmental quality (IEQ) and occupant satisfaction during summer-time. This paper provides a better understanding of the actual performance of retrofitted residential apartment buildings in Finland, focusing on some aspects of and the risk of summer overheating through post-occupancy evaluation (POE). Design/methodology/approach The study used both qualitative and quantitative data collection methods, including satisfaction surveys, indoor air temperature and relative humidity measurements, self-reported behaviour forms, open-ended discussions, and site visits in five apartments in different residential buildings in Tampere city, monitored during the summer-time, for at least 2 weeks at a time. Findings While occupants were positive regarding most aspects of IEQ, concerns about indoor air quality (IAQ), summer overheating and acoustic comfort were raised. The summer-time monitoring highlighted that indoor air temperatures could reach as high as 27 °C for 2–9 days depending on the monitored apartment. Little cloud cover and warmer outdoor temperatures directly influenced indoor air temperature overheating. For some aspects of the investigated IEQ parameters, it was noted that while occupants’ satisfaction was influenced by the length of their residence, their acceptance of the same conditions remained positive over time (i.e. more than one year) as they adapted over time. Research limitations/implications The number of participants and case studies was relatively small due to the well-known difficulty in gaining access to private homes, so the results do not allow generalisation but do provide interesting insights of these specific cases to be validated with future additional research. The short sequential rather than long-term parallel monitoring of the case study apartments was another limitation making comparison between cases and understanding reasons for differences difficult. Practical implications Findings highlight the need to maintain the performance of housing in Finland during summer-time. The highlighted subjective issues emphasised in this study underscore the necessity for enhanced pre- and post-retrofit quality processes and the prompt resolution of issues as they arise. The integration of POE studies into all residential construction practices becomes pivotal for the advancement of sustainable homes now, but also in the future, especially when subjected to a warming climate. Originality/value This study is among the few POE studies conducted in Finland, offering insights into post-retrofit performance and occupant satisfaction during the summer-time. The study highlights the potential of POE to understand the performance of retrofitted Finnish apartments from a user-centric perspective.