Demand Controlled Ventilation (DCV) is a control strategy which aims to vary the amount of ventilation air a system provides a space based on the real-time ventilation requirements (i.e. the ventilation demand) of the space. The term is used in a variety of contexts. Examples include garage ventilation systems which enable and modulate airflow off of measured CO concentrations in the garage, as well as kitchen ventilation systems which enable fans and modulate airflow off of temperature in the kitchen’s exhaust hoods. The example examined in this article is an air handling unit (AHU) whose minimum ventilation requirements are adjusted to meet the varying occupant density of the space it serves. This particular application of DCV has a common misunderstanding which this article seeks to set the record straight on.