The sound is similar to a "buzz" of a high voltage line or a transformer hum. The volume varies with the fan speed rheostat setting and not the actual motor rpm. (Well, more like the difference between the setting and the actual rpm)
Other than being annoyingly loud, is there any electrical danger here? Is it due to improper instalment or lack of adequate insulation?
I'm renting the apartment, so if it is a hazard, then it is the landlord's responsibility to repair it. Otherwise, how would I go about repairing it?