Quiet Exhaust Fan?
 

I'm looking for a quiet fan or two to exhaust air from the top of my canopy. I'm looking to draw 150-200 cfm in through the open back and blow it out the top.

I'm considering 2- 4" Icecap fans, but I'm not sure how loud they are when they're running full tilt.

You could use a central duct fan, it works on a pull/push rather than just a push as most fans do.

I use them in my house for ventilation and they are almost dead silent, and come in a variety of CFM ratings.

http://img.photobucket.com/albums/v6.../InlineFan.jpg

any hydroponic shop would have inline blowers and they are pretty cheap

If you dont mind wireing on to a 12V adaptor.
Check out computer fans as an option.

Don't waste the effort on computer fans... Head over to princess auto - they have computer-esque fans; that are 120v and I'm sure there are many members on the board who can tell you they are nice and quiet.

I used one of these on my projector, they are really quiet and have temperature sensing.
E-bay fans

Home Depot, Revy (Rona) and all the home hardware stores carry bathroom fans.

Doug

I was looking a those fans on eBay earlier today. The trouble is I would need 9 of them to cool my 180. Cheaper to buy 2 Icecaps if they're quiet enough. I might take a look in a hydroponics store. LOL Due to my tank switch over I had a big spike in my hydro bill. Now if I'm seen in a grow-opp store.....