Filtration of HVAC system for improved indoor air quality

A heating ventilation and air conditioning (HVAC) system comprising:

• an air handling unit having an air handling unit outlet;
• at least one zone having an inlet and an outlet, the at least one zone being operably coupled to the air handling unit outlet;
• a return air duct fluidly connecting the outlet of the at least one zone to the air handling unit;
• at least one sterilization system arranged within the return air duct at or directly downstream from the outlet of the at least one zone;
• at least one of an electronic filter and an ultraviolet light device arranged within the air handling unit, within a fluid flow path extending through the air handling unit;
• at least one indoor air quality sensor operable to monitor an indoor air quality within the at least one zone;
• and
• a controller operably coupled to the at least one indoor air quality sensor, the at least one sterilization system, and the at least one of an electronic filter and an ultraviolet light device;
• wherein the controller is configured to operate the HVAC system in a first filtration mode when the indoor air quality within the at least one zone exceeds an allowable threshold, wherein in the first filtration mode, the controller is configured to operate the at least one sterilization system, and in a second filtration mode the controller is configured to operate the at least one of an electronic filter and an ultraviolet light device arranged within the air handling unit, wherein an air flow output from a zone of the HVAC system is sterilized within the at least one sterilization system and within the at least one of the electronic filter and the ultraviolet light device arranged within the air handling unit in series.