Ceiling Exhaust Fan -How loud is .5 sones?

Can any1 please provide an example of how loud would .3 to .5 sones be?
Could it be equivalent with the machanism of a noisy cheapo DVD player?
*Please focus on sones (sound level?) and not going off topic such my room size, cfm, wattage, or other options like open the windows, adding AC lines or a return line, etc. Thanks
Panasonic has few of them that can generate .3 to .5 sones: http://www.rewci.com/panfv05.html
Could it be as quite as the little computer exhaust fan, any1 ?
I belive Home Depot has a display where you can hear various fans.
Your question is difficult to answer as the rating system is based on a number of factors, much like trying to calculate savings from insulation in an attic :^).

From the internet, a sone is a unit of perceived loudness after a proposal of Stanley Smith. Loudness is a subjective measure of the sound pressure. One sone is equivalent to 40 phons, which is defined as the loudness of a 1 kHz tone at 40 dBSPL.

The volume of a sound is a subjective perception. To "measure" loudness the volume of a 1,000 hertz reference tone is adjusted until it is perceived by listeners to be equally as loud as the sound being "measured."

The loudness level, in phons, of the sound is then equal to the sound pressure level, in decibels.

Short answer, (In my opinion), If the fan is near you and you have a very quiet room you will hear it.
"I belive Home Depot has a display where you can hear various fans."

Thanks Jd,
It's great if they have many of them side-by-side for testing and I'd be greatly delightful & will keep that in mind.
However, unlike my WELL TREATED HT room, the noise inside home depot is tramendously loud. It's like audition new pair of speakers sharing a room with a jet engine running. Lol.
"Short answer, (In my opinion), If the fan is near you and you have a very quiet room you will hear it."

Thanks Albert,
If any1 can confirm .3 or .5 sones is as noisy as the back of the computer fan, that'd be ecellent and I can live with that.
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
Forget Sones those are all WAY to loud - sound like jet engines. You need something with DbA of around 10 at one meter (a big very slow moving fan if you want to move a lot of air). You can hear about 15 to 30 db below the noise floor and this means you will hear any and I mean any bathroom type evacuation fan.

You will need to go custom, IMHO.

Here is a Calculator
Here's some info....


I run a whisper fan that is rated at about 30db,too lound. So I have reduced the fan speed in half and sitting 4ft away i can barely hear it.

If I read the graphs right .5 sone = 30 phons which in db level would be about 30db. I think you need to put a potentionmeter on this fan and reduce the speed in half.
Does it have to run while listening/watching, or can it be turned on and then back off, or during some other times?

Noise then wouldn't be as integral an issue.

Insulating the housing the fan would reside in would attenuate the sound... like a whisper box for a projector or what ever they call that added box surrounding the PJ.

Speaking of which, with the lamp turned up to full brightness I can hear the PJ runing... until I turn up the sound of the whatever... Flick, CD, etc. Then of course, the noise is not a consideration.

Adding to the insulation of the fan housing, or even setting it into a duct work which turns by 90 degrees should also diminish the noted or audible sound of the motor itself. Further lengthening the ducting, and thereby removing the fan still farther away will surely decrease the noise it makes.

Go with a large register as you can too. that will help.

Good luck.
Yes,the exhaust fan must run when the system is on to get the heat up on attic. Reason I'm looking for maximum quiteness is because I listen to soft music on low volume normally at 2 to 4am. So basically, at these hours, I will hear everything else as well.
I just read an DIY article about an exhaust fan with .5 sones and the author gave a real life example: In his bedroom, the fan ran very quite that he was 10' away and he couldn't tell if it was On or not. That's a very good info for me.
I just read an DIY article about an exhaust fan with .5 sones and the author gave a real life example: In his bedroom, the fan ran very quite that he was 10' away and he couldn't tell if it was On or not. That's a very good info for me.

The guy is either deaf or he lives 200 feet from a major highway. O.5 Sones is loud.
Is your attic finished? If not, I would mount the fan in the attic (not in the ceiling of your listening room) on top of the joists - utilizing good damping material between the fan and the joists (do a search for after-market noise isolation mounting materials/products). You can easily construct a duct between the fan and the ceiling of your listening room -which can also be damped (provided that you don't obstruct air flow). The duct work must be air-tight to insure maximum ventilation – I would suggest avoiding metal/tin duct work, as it is noisy (MDF may be a better solution. Make sure you damp the duct work from the fan, as the ductwork can act like a speaker cabinet – projecting the sound back into your room. This will not eliminate all of the mechanical noise, but it will reduce the noise compared to mounting it directly in your ceiling.

Note: you can also tweak the fan itself with damping materials (i.e.: soft fan/motor mounts, silicone motor mounts, etc.). The thing is, you want to decouple the fan from the mounting area (in this case your house).

.5 sones at what CFM? How many BTU of heat will the fan be required to remove? Will the fan be mounted above the audio equipment? Does the HT room have heating as well as air conditioning? Forced air? Can you hear the heating/ A/C coming through registers?
Got talked into replacing two bathroom exhaust fans for a good friend and customer some years ago - half way thru the project I understood why his regular handeyman had passed on it.My buddy wanted less racket in the bathrooms of his buisness - found the quietest rated fans available about 6 or 7 years ago.After mucho struggle installed them.Results were: One fan was somewhat quieter than the old unit I replaced - very definitely not inaudible. Second unit was basically pretty much as noisy as when I started because most of the racket was coming from tin vent pipes banging around -couldn't get at these (120+ year old building)- so no joy.
Based on this very limited experience - I'd suggest that none of the "bathroom" fans are going to be quit enough for you. Remote mount the fan and use the flexible "plastic" HVAC duct to get to your room - while I'm sure you can find really quit fans ( try contacting folks who build recording studios)- I think it'll be a "ma hand me the nitro" moment when you see how expensive they are.
I will offer my thoughts from a different perspective. I have had very extensive experience with Panasonic fans. We currently have five of them in our home. Bottom line, they are 'spooky quiet'.

The largest unit that we have, the FV20VQ3, which is rated at 190cfm and requires 6-inch ducting, is in-audible from ~10 few away, and is barely audible standing directly underneath it.

Sorry I cant answer your question directly, but this is real world experience. I have chosen to install all of them with timers as it is SO VERY easy to mistakenly leave them on because they are so quiet.
I installed the panasonic whisper stink fans in my bathrooms and put a 150cfm one in the ceiling of my HT room just behind my head.
I often will run it to evacuate smells coming from the kitchen while watching TV. Its barely noticable. The panasonic whispers are worth the extra money.

I also purchase large fans for hvac air scrubbers I dersign and have a sound calculation tool in front of me from LorenCook fan suppliers.
Sones .3-.5 = 14.5-15.5 dbs
Im sorry I misread the tool,
.3 sones = 12.6 db,
.5 sones = 17.5 db.
But that is at the source,
figure your ears 5 feet away will reduce that by maybe 5dbs
Excellent numbers, greatly appreciated. After carefully consider all possibilities, I've decided to go back to my first plan.
Great to see you, Shadome, and some others have the technical ability and taking this hobby seriously.
As others have pointed out, what is quiet for me may be loud and obnoxious to you, especialy at 2am in quiet mode.

There are some great ideas here for decoupling the mechanical noise and remoting the fan farther up into the attic.
Might look at picking up a dayton fan thru grainger and mounting it up in the attic farther, rather than on top of the sheetrock.