Patent attributes
A Heating, Ventilating Air Conditioning (HVAC) fan control method to detect an HVAC fan is controlled by at least one fan-on duration control selected by a user and provide at least one fan-on alarm message prior to overriding the at least one fan-on duration control. The method monitors an occupancy sensor signal to determine an occupancy in a conditioned space served by an HVAC system and automatically overrides the at least one fan-on duration control to save energy when the conditioned space is unoccupied. The overriding may comprise operating the HVAC fan based only on a thermostat call for cooling or a thermostat call for heating, operating the HVAC fan for less time than the at least one fan-on duration control selected by the user, and operating the HVAC fan for less frequency than the at least one fan-on duration control selected by the user.
