Customer concern was noise at startup and shutdown of the heat and more noise from the second floor return during operation. Increased set point to initiate a call for heat. The audible click of the humidifier water solenoid valve could clearly be heard throughout the hoise. The noise from the second floor return was the fan of the humidifier transmitting noise through the ductwork. Cycled humidifier on and off while customer stood under the return grille. He verified the noise was the humidifier and asked it be shut off. Explained the benefits of the humidifier and the maintenance requirements for it. He said his small child is scared of the noise and wishes to not use it as a result.