Experiences from nine passive houses in Sweden – Indoor thermal environment and energy use

This paper presents experiences from a recently built area with passive houses in Linköping, Sweden and compares them with conventional buildings, mainly from an indoor environment perspective, but also based on energy use. The built area consists of 39 recently constructed terraced houses, of which nine are built according to the passive house standard. The aspects of thermal comfort as well as local discomfort are studied. The methodology is based on on-site measurements and two types of simulations – CFD and Building Energy Simulation. In addition a post-occupancy evaluation was made using a standardized questionnaire to relate the occupantʹs perception of the indoor environment one year after the buildings were completed. The thermal comfort for these newly built passive houses is well within the limits in the local building code. However, some interesting findings related to local comfort such as cold floors are found in the post-occupancy evaluation as well as in the predictions. The occupants of the passive houses experience cold floors to a higher degree than in the conventional buildings. It was also shown that there are a higher number of complaints related to high temperatures during summer in the passive houses. It is worth noting that the buildings do not have external shading installed by default. The effect of varying temperatures was also observed in the passive houses to a higher degree than in the more conventional buildings, especially related to cooking and other heat-generating activities, which is normal in a more well insulated and airtight building.