When a ceiling fan makes a humming noise, a whole host of possible problems could be the cause. The way to get rid of the sound also presents a multitude of possibilities. These range from throwing away the fan to some fairly simple fixes. Getting rid of the noise can be frustrating because it is often a matter of trial and error.
Troubleshoot the motor. When a fan has a humming (or buzzing) sound, the motor is most likely the reason. A motor that lacks oil will burn out. Make sure the fan has the proper amount of oil. Many fans are maintenance-free, but some do require that you add oil. Add oil to the small hole above the motor. Run the fan for a day, if it has not been in operation for a long time. A humming fan can indicate the motor's bearings must be lubricated by the operation of the fan.
Tighten loose screws. A loose part can cause a noise. If a fan has a light fixture, tighten any screws there as well. Make sure the light bulbs are not touching their covers on a fan with a light fixture. Adjust covers so they are no longer in contact with the bulb. Tighten the screws of the plate where the fan is attached to the ceiling.
Look for an electrical problem. A dimmer switch can cause a fan to hum, and most ceiling fans are not made to work with a dimmer switch. Install the proper electric switch to stop the humming noise.
Check the fan's balance. An unbalanced fan can cause a humming noise. Balance it with a fan-balancing kit.
Run the fan at different speeds. One speed may produce more of a humming noise than others. Ceiling fans also often hum at lower speeds. Run the fan at a higher speed, a medium speed and lower speed. This may stop the humming.
Look for broken or bent blades. A damaged blade can create noise and must be replaced.