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.

Although many passive houses and low-energy houses were evaluated while they were still newly built, there has not been much evaluation of them in Sweden after several years? occupation. This indicates a need to re-visit older passive houses in order to pick up any aspects that could be im-proved 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 experience 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. Interviews, follow-up of energy use and measurements of indoor conditions and the performance of technical systems have included indoor thermal conditions, solar collector systems, performance of heat exchangers, air flows, acoustic conditions, airtightness of the building envelope, natural cross ventilation when required, moisture conditions in the building envelope and operating instruc-tions. The results shows that, in general, the occupants are very satisfied, although they have put for-ward proposals for certain improvements, linked to the fact that it is they themselves who operate and look after the houses. Similarly, measurement and monitoring of the indoor conditions and the technical systems shows that, in many respects, the houses have aged well, although there is also scope for improvement in order to ensure that the initially low energy consumption does not tend to increase, and to maintain the good indoor environmental conditions. The project has been financed by SBUF and the Västra Götalandsregionen.

I rapporten presenteras resultat från en del av Milparena projekt som rör åtgärder på byggnadsskalet och installationssystemen som har gjorts för att öka energieffektiviteten i byggnaden. Dels presenteras ett antal pilotprojekt och de åtgärder som har utförts i dessa projekt. Ett antal metoder för att tilläggsisolera, byta fönster och lufttäta klimatskalet presenteras. En renovering kan innebära förändrade tryck- och fuktförhållanden som kan påverka såväl värmebehovet som byggnadskonstruktionens beständighet och innemiljön i byggnaden. I rapporten presenteras därför ett systematiskt sätt, hur man undviker eventuella risker för oönskade konsekvenser genom att göra undersökningar av byggnadernas tekniska status före renovering, simuleringar av hygro-termiska förhållandena för olika alternativa renovering metoder, uppföljning och kontroll av resultaten i bygg- och bruksfasen. I rapporten presenteras även dokumentation av befintliga och utveckling av innovativa värmeåtervinningssystem för miljonprogrambyggnadernas typiska ventilationssystem, en systematisk genomgång av befintliga och utveckling av nya värmesystem samt varmvattensystem. Den senaste tidens utveckling av styr och mätsystem ger helt andra möjligheter till återkoppling än de som fanns när miljonprogrammet byggdes. Inom projektet har därför också en systematisk genomgång gjorts av metoder att minska värmebehovet genom förbättrad mätning och driftsövervakning.