Utvärdering av äldre passivhus: Hållbarhet och renoveringsbehov efter 10-15 år

This thesis investigates the indoor climate of passive houses that are 10–15 years old, with a focus on evaluating resident comfort, identifying renovation needs, and providing recommendations for future construction. The study is based on a literature review and a survey directed at residents living in older passive houses in Sweden, aiming to highlight any shortcomings or challenges that have arisen over time and to contribute to the body of knowledge on the long-term performance of passive houses. An empirical method was applied, five condominium associations with certified passive houses chose to participate. A total of 212 households were included, of which 32 responded to the survey about their experiences living in a passive house. The survey covered aspects such as comfort, indoor climate, and suggestions for improvement. To strengthen the analysis, the survey results were compared with recent research studies on passive house performance, offering a broader understanding of both user experiences and the technical functioning of the buildings over time. The findings indicate that overall satisfaction is high, especially in terms of low energy consumption and quiet indoor environments. However, several households reported recurring issues related to indoor climate, such as overheating during summer and cold floors in winter. A key theme in both the literature and the empirical data was the absence of solar shading, which proved to be a critical factor in preventing overheating. This is particularly relevant since passive houses often feature large window areas to optimize solar gain, which can lead to excess indoor heat during the summer. The study therefore recommends that solar shading be installed prior to occupancy as a standard solution. Several issues were linked to incorrect or insufficient installations, which is particularly problematic in passive houses that rely on airtight construction. Even minor faults can lead to significant consequences for both comfort and energy performance. The need for advanced ventilation systems with summer bypass functions, as well as improved information for new residents, were also highlighted as important measures. The results emphasize the importance of a holistic perspective in both new construction and renovation of passive houses. Through technical improvements, quality control, and resident education, it is possible to ensure that these buildings reach their full potential over the long term.