Analysis of Measured CO2 Levels through Long-Term Monitoring in Renovated Multifamily Buildings: A Common Case

Abstract

The purpose of this study was to analyze the indoor air quality, in particular, the CO2 level, in a real environment, within 16 apartments located in the municipality of Zalău, Romania, in five recently renovated multifamily buildings in which families live under normal conditions. Long-term monitoring was undertaken for 4.5 months, during the heating season of 2022–2023. A representative microclimate perspective was analyzed: the median value of the time fraction, which exceeded the Indoor Environment Quality Category I (IEQcat I) threshold for adults’ bedrooms was 82.30%. For children’s bedrooms, it was 75.65%, while for living rooms, it was 58.78%. When considering IEQcat IV, it was identified that for the bedrooms, the time fraction for which the threshold values were exceeded was still significant (median value of 45.37% for adults’ bedrooms and 50.14% for children’s bedrooms). Even if the indoor thermal comfort conditions increased, it was found that for almost half of the time, the bedrooms did not provide a health-safe indoor environment for the occupants due to inadequate ventilation, exceeding the health threshold values. Thus, it was identified that the ventilation of buildings is a key issue within the renovation process and, currently, is not properly undertaken for the mass renovation of existing multifamily residential buildings.

Ventilation Methods for Improving the Indoor Air Quality and Energy Efficiency of Multi-Family Buildings in Central Europe

“…The obtained results showed small differences between ventilation system in terms of human thermal comfort in rooms with low thermal inertia, but indicated energy and economic efficiency of the passive ventilation system. In turn, Măgurean and Petran [24] analysed the indoor environment in sixteen apartments located in Romania in five recently renovated multi-family buildings. Even if the thermal comfort conditions in the rooms increased after modernisation, it was found that almost half of the time the bedrooms had poor indoor air quality due to inadequate ventilation.…”