US Patent 9347678 Distributed indoor air quality control module and method

An indoor air quality (IAQ) control module may be provided for sensing and controlling the indoor environmental quality (IEQ) of a zone in a building. The IAQ control module may receive a supply air sample from a supply vent and a return air sample from a return vent, where the air samples are taken using the pressure created by a blower within the HVAC system. The IAQ control module may then compute a differential value for each of the sensed one or more air parameters and generate a control signal or command based on at least the differential value(s). The IAQ control module may then communicate the control signal to an airflow control device to control the airflow to and/or from the zone.