Exploring indoor climate and comfort effects in refurbished multi-family dwellings with improved energy performance

The building stock in Sweden includes many older residential dwellings often with inadequate building envelopes and poor insulation resulting in high energy use and uncomfortable indoor climate. Improving energy performance in multi-family dwellings by refurbishment processes is the key factor to success in order to meet national and European energy goals to reduce energy use in the building sector by 50 % through 2050. How is indoor environment affected when dwellings are refurbished to become low-energy dwellings? This paper aims to explore parameters for indoor climate and comfort in refurbished dwellings transformed into low-energy dwellings from an inter-disciplinary perspective, taking into account both quantitative and qualitative aspects of indoor climate using technical measurements, a questionnaire survey, and qualitative interviews. Based on a combination of methods, the results show that the indoor climate has largely been improved and user satisfaction was high in the refurbished dwellings. Results also showed that however indoor temperatures were too high during summer, resulting in dissatisfaction from residents. Overheating can be prevented by providing information to the residents about the functionality of the heating system and by adding shade in front of the windows