Passive mitigation of overheating in Finnish apartments under current and future climates

Greenhouse gas emissions are causing global average temperatures to rise, and Finland will experience an increase in the frequency and severity of hot weather and heatwaves in the future. Finnish buildings are built for the cold, and there is a need to adapt housing to protect against heat. This study examines how individual and combinations of passive adaptations can reduce overheating in three modern structural timber case study apartments in Jyvaskyla, central Finland. The modelling tool IDA Indoor Climate and Energy is used to simulate indoor temperatures and energy consumption under current and predicted typical future (2030, 2050 and 2100) climates. Results show increasing overheating risks in the future, with the effectiveness of passive mitigation strategies varying by type and climate scenario. The most effective individual adaptation is daytime natural ventilation, while the most effective combined solution is natural ventilation and external shutters, which eliminate overheating in Jyvaskyla until the 2100s. The effectiveness of occupant-controlled passive measures supports their use to reduce cooling demand, increasing passive survivability and enabling occupant adaptive comfort. Changes to building regulations and overheating modelling standards in Finland may be required to exploit the full potential of passive overheating measures and reduce reliance on active systems.