A thermostatic actuator for a radiator valve includes a thermostat mechanism configured to passively open the valve when an environmental temperature is less than a set point and to close the valve when the temperature is greater than the set point. A set point adjustment mechanism draws power from a power supply to selectively drive unitary movement of the thermostat mechanism to adjust the set point. Multiple actuators are used in a zoned radiant heating system in which a controller is operatively connected to the set point adjustment mechanism of each actuator to selectively transmit a control signal to actuate the set point adjustment mechanism to drive unitary movement of the respective thermostat mechanism to adjust the respective set point.