Performance of ventilation in Estonian apartment buildings

Abstract

In this study, the performance of ventilation and air change in Estonian apartment buildings with different ventilation systems is analysed by field measurements. 189 apartments from 107 buildings with natural and mechanical ventilation were under investigation. Airflow and CO 2 levels were measured in the heating period and summer period. The airflows in apartments were estimated using the metabolic CO 2 method. Measurements were carried out in the kitchen, toilet and bathroom. The analyse shows that the average air change rate of concrete and brick buildings was 0.24 h -1 and average airflow per surface area of the apartment was 0.17 l/(s∙m 2 ). The total exhaust airflow corresponded to the target values of indoor climate category II in none of the apartments, and in only 5 % of the apartments did it correspond to climate category III. The average air change rate of the newly built (>2000) apartment buildings was 0.42 h -1 , and average airflow per surface area of the apartment was 0.3 l/(s*m 2 ). In 7 % of the new apartments, total exhaust airflow corresponded with the target values of indoor climate category II and in 23 %, of climate category III. The technical inspection of studied ventilation systems shows that natural ventilation systems are in poor condition. Main problems have to do with insufficient installation quality of channels and exhaust devices and lack of compensation airflow from air building leakages. The main reason for the reduction of the exhaust air flows is related to the low supply air temperatures in cold period. Finally, the principles for the renovation of ventilation systems to provide better indoor climate and energy performance, are also discussed.