The energy efficiency of the intelligent building envelope solutions in Finnish apartment and office buildings

This study investigated the effects of intelligent building envelope solutions (automated blinds, openable windows, awnings, and electrochromic windows) in Finnish old and new apartment buildings as well as old and new office buildings. Moreover, the results are compared to the passive solutions (manual blinds and solar protection windows). The main goal is to analyze the energy efficiency of these solutions and to compare the performance of each solution in improving the indoor temperature conditions in Finland’s current climate. Therefore, the solutions were simulated with the usage of mechanical cooling in the living rooms of apartment buildings, and with mechanical cooling in spaces and ventilation in the office buildings. According to the results, electrochromic and solar protection windows are the solutions with the lowest district heating consumption in the old apartment and office buildings due to the lower U value. However, they cause an increase in district heating consumption with the reduction in solar heat gains in the new apartment and office buildings. The electricity consumption in the cases with the electrical openable windows in both new apartment and office buildings is the lowest. While in both the old apartment and office buildings, the cases with electrochromic and solar protection windows are the ones with the lowest electricity consumption. Considering the indoor temperature conditions, solar protection windows, electrochromic windows, and openable windows are the solutions that cause lower temperatures in both building types during the cooling season.