An air change is how many times the air enters and exits a room from the HVAC system in one hour. Or, how many times a room would fill up with the air from the supply registers in sixty minutes.
Engineering room airflow may present a real challenge when balancing an HVAC system. Most calculations only use the heat loss or gain of a room to decide on required airflow and often don’t take into consideration required room ventilation needs. Let’s take a look at how an air change calculation may simplify this step in your air balancing.