Experience and evaluation of ten-year-old passive houses – indoor environment, durability and user convenience Although many passive houses and low-energy houses were evaluated while they were still newly built, there has not been much evaluation of them after several years’ of occupation. This indicates a need to revisit older passive houses in order to pick up any aspects that could be improved in the interests of operating aspects, good indoor environmental conditions, moisture safety or continued low energy use. The objective of this project has been to provide the building sector with feedback of experience from the first passive houses in Sweden, which were first occupied in 2001. User experiences have been collected through interviews, and indoor environmental conditions and the performance of technical systems have been monitored and measured. Energy use data for the houses has also been obtained. The work has been carried out on ten of the twenty terrace house units that were built outside Göteborg. As the houses were thoroughly monitored while they were new, we can see if and how they have changed over their first ten years’ occupation.