AC 240V fans

[Excalib12e]

im using an ac fan for something now and its quite noisy..

[tawauboy]

dc fans can be noisy too.
if the fan speed is fast, it does not matter whether it is a dc or ac fan.
use slower speed fans if quiet operation is one of the criteria.
for dc fans, choose something that required < 150ma.

[Excalib12e]

or u could use a fan controller sold in sls .allows u to control e speed so u can lower it when its noisy,..

[tawauboy]

fan controllers for ac fans are usually expensive as these are usually ac inverters. by controlling the frequency of the ac, the fan speed is controlled.
dc fans can be controlled by cheaper pwm controllers. again, these are quite expensive. if you know electronics, you can diy these circuits based on information available from the web.