There is no fan.
I've got one, I love it! There is no fan. It keeps cool by radiating heat out through the case. However in my experience, it barely gets even warm to the touch. The heat issue is not a concern. As far as other operational noise, it makes little "chirping" sounds when it accesses different tracks on the disk. Otherwise its motor is very quiet, it won't bother you a bit. The blue power light is quite bright though, and will tend to light up a darkened bedroom. BTW, as I've posted before, the FW800 portion is a "pass-thru" for the FW400 -- so if you're using it with a FW400 interface, you can buy a plug adapter and use the FW800 socket too.