Ceiling Exhaust Fan -How loud is .5 sones?

Thanks Albert,
If any1 can confirm .3 or .5 sones is as noisy as the back of the computer fan, that'd be excellent and I can live with that.

Computer fans vary a lot, and the distance your ear is from that fan is also a factor. How far from this fan will your ears be?

What else is going on the room that might mask (compete) with that noise?

You will probably be able to hear it from the next room. When I remodeled our last house, researched "quiet" bathroom fans. Even the quietest ones were pretty loud - they spin fast.

From the HGTV website: One sone is about equal to a refrigerator running, while four is equivalent to normal conversation.

OK, I'm risking your wrath because what I am going to suggest is not rated in sones....but, FanTech inline exhaust fans allow you to locate the fan itself far from the listening room, so that you don't hear the fan motor at all. You only hear the air moving through the grate. In my BR with the 100 cfm fan on full, you can hear the air quite easily through the 6" grate. At half speed it is totally silent. I'd guess that an oversized grate would make it quieter, perhaps even silent, at the highest setting. Unfortunately on their site FanTech doesn't list sound ratings, because they say that there are no testing standards for remote mounted fans.

Panasonic has a very nice poop fan extractor rated at 3 sones and then they have the very same fan listed as a retro model thats 4 sones. Depends how and on what material the same fan is mounted. Yours for only 399,95. The same fan will have a different sound in a different room depending on size and material build out. Tom

Thanks Aby,
Since I wanted to avoid ANY unwanted sound in my HT room, the design that you mentioned (relocate the fan futher away) was first on my drawing board. But if .5 sones is an exeptional number, then I can live with it. Problem is, what is .5 sones equivalent to realife example?
This is what you are talking: http://www.youtube.com/watch?v=B-qWg60xFtY