Atmosphere Vortex 711 CFM S-Line S-800 Fan, 8"

Me likey a lot :-) You would need the dial-a-temp thingy from them, to lower the speed. Almost nothing, from what I heard, is compatible with it.

When you first turn this thing on it sounds loud, until you realize that's the sound of all that air moving, not the motor. I do think the "ultra quiet" claim is a bit of stretch, considering it's exactly the same decibels as almost all of the other top choices, but it is a great fan. Even dialed all the way down with a speed controller (sold separately) it still moves a ton of air. And it looks cool too!

This fan is being used to extract welding fumes in a small hobby shed. It's very powerful, not too noisy and the setup was easy. I recommend this wholeheartedly!

Have only tested the product in place at this point. It is located in my attic using an insulated duct that also has another layer of insulation around it. When on full, as I tested it, yes you could hear the flow of air as it moves a lot of air. However, it is not what I expected reading some of the other reviews. Once I have my speed adjustment working, I will not need to use the full volume. Bottom line, much quieter then expected. Do not suggest using this in an open space or the noise might be an issue, but for an enclosed area......does the trick. Highly recommended for an attic or out of the way installation.

UPDATED review: 7 years old and still working great. This fan is used about 24/7 for about 6 months of the year and sporadically the rest of the year. It still works great, still moves lots of air, still fairly quiet. (It's mounted high in the attic and you can just barely hear it run inside the house.)UPDATED review. 3 years old.No fan is perfect. If you get a lot of air movement it's noisy. If it's cheap, it vibrates or has a 90 day warranty. This fan is the best compromise fan I've found. It has a good CFM/dB ratio, ie moves a good amount of air without being too noisy. It is not quiet, but you can sleep with it running if you plumb it with 10" duct (lowers the noise alot.) It is much more expensive, but it's got a great warranty and does not vibrate the structure. The mounting is easy, but the clamps are .... a bit on the cheap side. I would really appreciate a more robust system for that. But overall, it's the best I have been able to find.Original review:This is well made and fairly quiet. It's also very well balanced and does not vibrate like the cheap fans which typically are unbalanced. However the price of this fan is just too high. There are other fans, 10" and 12" that are much, much cheaper and flow 50% more air than this. However they are a louder and vibrate like crazy. When you buy this fan what you are paying for is:#1. Somewhat quieter for the same volume of air.#2. Easy to mount and hook up to.#3. Very well balanced, will not vibrate the house or rafters.#4. Looks good.But most all good 8" fans will move 700 or or so cfm, 10" fans move about 900 to 1000 and 12" fans move 1100 to about 1200 cfm, I've seen some rated at 1400 cfm. However their cost is less than this 700 cfm fan.So if the volume of air movement is your priority, this is not the fan for the money.If looks, ease of mounting, smooth non-vibrating operation and a reduction in noise, then this is the fan for you.10 year warranty, so far so good.