A retrofit module configured for use with a door closer having a pinion. The retrofit module generally includes a case, an output shaft, a motor, and a control assembly. The output shaft is rotatably mounted in the case, and is configured for rotational coupling with the pinion. The motor is mounted to the case, and is operable to rotate the output shaft in a door-opening direction. The control assembly is mounted to the case, and is configured to operate the motor to drive the output shaft in the door-opening direction in response to an actuating signal.