Various highly infective pathogens that are present in hospital wards can spread through the air and infect patients. To remove pathogens effectively in order to reduce infections, the efficient ventilation of hospital wards is critical. This study used age of air data to analyze the ventilation efficiency within hospital wards. The validity of the numerical analysis method was verified by comparison with the age of air data obtained from an experimental test on a four-bed hospital ward. The verified numerical analysis method was used to establish the airflow within a hospital ward in relation to the use of ventilation systems, air cleaners, and individual patient curtains. The efficiency of ventilation according to each factor was compared using age of air data. Considerable differences in the age of the air were identified, depending on the location of the patient with respect to both the air cleaner and the inlet/outlet duct of the ventilation system. Furthermore, individual curtains were found to interfere with air circulation, reducing ventilation efficiency and increasing the age of the air at the location of each patient.