Evaluation of ventilation performance and occupants’ ventilation practice in a renovated multi-floor apartment building with hybrid ventilation: A case study

This study presents a case study that evaluates the performance of ventilation system in two renovated 12-floor residential buildings in Norway. New room ventilation units (RVUs) with heat recovery are installed in each apartment. The results from questionnaire survey reveal that 42% of respondents never use the RVUs, while 44% operate them daily. Dynamic simulations in IDA ICE are performed with different ventilation scenario to evaluate the air quality in master bedrooms. The results show that both RVUs operation and window opening can provide satisfactory air quality; without these ventilation methods, high CO2 concentrations are observed, with the average CO2 concentrations exceeding recommended threshold of 1000 ppm in most months. It is recommended to implement a more effective control strategy in the new ventilation system.