INFLUENCE OF URBAN AND MICROENVIRONMENT PARAMETERS ON APARTMENT OVERHEATING DURING HEATWAVES IN THE NORDIC CLIMATE REGION

Due to climate change, there is an increased risk of apartment overheating. Apartment overheating reduced thermal comfort and it could create health problems for the elderly and vulnerable persons. In Nordic countries, long heatwaves have not been common in the region in the past and hence apartments are not equipped with mechanical cooling systems. This study is based on a large dataset of indoor air temperatures of apartments in the Helsinki region. The research evaluates the influence of the urban microenvironment on overheating. In this study, the green view index, building density and distance from the sea are used to analyze the overheating of apartments. We created a data model based on the combination of the aforementioned parameters. The buildings are clustered into groups, representing their direct and combined effect on overheating. The overheating risk was assessed based on heatwave data from the summers of 2018 and 2021. The results are presented as mean indoor air temperatures of each indicative group for the entire summer and heatwave period and show consistent correlations between groups. The best-performing group has a 1.2 °C lower temperature than all groups’ average during the whole summer and 0.9 °C during the heatwave. The building groups with higher green view index showed the ability to endure heatwaves more. Long heatwaves showed the ability to significantly lower the influence of urban factors, thus requiring more alternative approaches for passive or active cooling.