in our apartment, our master bathroom is immediately next to the master bedroom. our downstair neighbor's master bathroom is immediately beneath ours. and she likes to turn on the vent when she uses her master bathroom.

the noise from the vent is in fact not too much. but unfortunately she likes to use the vent around midnight when everything is very quiet. at that time, the noise is strong enough to keep us awake. closing the door of the bathroom doesn't help. and our neighbor usually uses the vent from 11:30 to 1:30 for at least one hour. occassionally, once between 2:00 and 5:00 for about 5 to 10 minutes. it wakes me up every time she uses the vent.

talked to the management, they replaced the fan in the vent quickly, but it doesn't help (i guess the floor is not thick enough to stop the vibration). i hoped they could talk to our neighbor, but appearantly they don't want to. (they suspected that I was too sensitive. they can always say that, but i don't think so.) i had to leave a note to our neighbor. now she uses the bathroom shorter, usually about 20 minutes. still a problem, but much better than before.

to put it short, the insulation is the problem. i cannot hear our neighbors, but the noise from the vent (which is immediately attached to our floor) is such a big hassle.

other than this, i have no complain.