A modular damper system is configured for installation in a ductwork of a building that supplies conditioned air through a register vent of the building and includes a damper unit, a control module and a power module. The damper unit is mountable upstream of the register vent and includes a damper that is movable between a closed position and an open position. The control module includes a controller that provides control commands to the damper unit and includes a housing that is configured to be secured to the ductwork at a position between the register vent and the damper unit. A power module is electrically coupled to the control module to provide power to the control module and includes a housing that is configured to be secured to the ductwork at a position between the register vent and the damper unit.