Although a ceiling fan is an excellent energy saver that can both cool and heat a room, it is bothersome when the fan produces an annoying buzzing noise. This is particularly true when you are trying to fall asleep, or just enjoying some peace and quiet. Ceiling fans can make a buzzing noise for a variety of reasons, so finding the source and stopping the noise may require some trial and error.
Check for electrical problems. A dimmer switch can cause a fan to buzz. Most ceiling fans are not made to work with a dimmer switch. Install the proper electric switch to stop the buzzing noise. You can also rig the fan to operate with its pull chains, as opposed to a wall switch.
Check the fan's different speeds. One speed may produce less of a buzzing noise than another. Ceiling fans often buzz at a lower speed. Run the fan at a higher speed, and then lower it. This may stop the buzzing.
Many ceiling fans have a light fixture. Check to see if one of the covers for a light bulb is loose. Check to make sure none of the light covers are clicking against the light bulb when fan is running. Adjust cover so it's no longer in contact with the bulb.
Loose screws can cause a buzzing sound. Tighten the screws that attach the blades to the motor. Tighten any other screws, including the screws that attach the fan to the ceiling.
Run the fan for 24 hours. Fans that have not been in operation over an extended period of time can produce a buzzing sound that indicates the motor bearings need lubrication. Most fans lubricate themselves while running. Lubricate fans that do require maintenance with a light machine oil.