Muffle bathroom vent fan?

Any ideas on how to muffle a bathroom type vent fan? I tried it out
at the store and it wasn't too bad, but after getting it installed at
home, this thing is almost deafening. The drone of this is incredibly
obnoxious.
What I suspect is the problem is that in the store the fan was setup
to push into a "dead" duct, so there was little air movement and thus
little noise. Now in my installation at home, there is a lot of air
moving and also a lot of noise.
For reference - fan is 8" with a baffle rated at 180CFM and 6.5
sonnes. Can I place some sort of smooth venturi type restriction in
the exhaust side of the fan to quiet this down a little. I don't need
this much airflow.
I installed it to draft warm air up the staircase and to stuff it into
the attic. Before I used to alway open the attic access door and let
the attic vent fan draw air as it needed. This worked fine, but the
attic access was in the closet in our master bedroom, neccessitating
leaving doors open and the hazard of loose insulation ending up on the
clothes in the closet.
It accomplishes the desired effect of cooling the house(quite well
actually), but the noise isn't tolerable. I have it wired in parallel
with the thermostat switch for the attic fan, so it only runs when the
attic starts to get to warm but it needs to get muffled somehow.
Ideas?
JW
Reply to
Jeridiah
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Check the mounting. Are the screws evenly and gently tightened? You might try loosening them a skoach when the fan's running, if you can. Then slowly ease them back in. I had a real noisy muffin fan in a Miller welder that got quiet when I tightened the screws.
Grant
Jeridiah wrote:
Reply to
Grant Erwin
||Any ideas on how to muffle a bathroom type vent fan? I tried it out ||at the store and it wasn't too bad, but after getting it installed at ||home, this thing is almost deafening. The drone of this is incredibly ||obnoxious. || ||For reference - fan is 8" with a baffle rated at 180CFM and 6.5 ||sonnes. Can I place some sort of smooth venturi type restriction in ||the exhaust side of the fan to quiet this down a little. I don't need ||this much airflow.
Mask the impeller Depending on what shape the fan and motor is, you may be able to fasten a thin disk of plastic or aluminum (metal content) to the face of the housing or even the blade to remove some of the blade surface. It might be more effective to make a large "washer" to mask of the outer inch or so of the fan (front or back) since that's there the highest speed is and probably the source of most of the noise. Texas Parts Guy
Reply to
Rex B
Egad. First thing would have been to pay attention to the sones rating before purchase, or return it and buy one with a _much_ lower rating.
If you want to choke it down, it need not be all that complicated - put a damper in the duct.
Reply to
Ecnerwal
Some folks like that. Loud fans, that is.
Womenfolk mostly. That means they don't have to run the water in the basin to mask the sound of the water running into the toilet.
Jim
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Reply to
jim rozen
Sometimes just a small reduction in speed makes a lot of difference in the noise level. A couple of ways to do that, a bucking filament transformer, secondary 12 to 24 volts, a series light bulb, choose the wattage to get the speed you want, or (outside chance) a lamp dimmer that may or may not work with an inductive load.
Earle Rich Mont Vernon, NH
Reply to
ERich10983
On Mon, 12 Jul 2004 13:18:17 -0700, Grant Erwin calmly ranted:
0.5 to 2.0 sones is considered quiet. He bought a 6.5 sone fan.
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shows listings only up to FIVE sones.
Exchange it for a quieter style or learn to live with it, Jeridiah. P.S: Shy people LOVE noisy bathroom fans.
P.P.S: Venting stairway air to the attic? Have you looked into using a thermostatically controlled louvre in the ceiling instead of a fan?
----- = Dain Bramaged...but having lots of fun! =
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Reply to
Larry Jaques
The Bathroom Fan FAQ has some stuff on this
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In short, use an inline fan, mounted as far as possible from the inlet. mount it on wire or strapping. Use a GOOD quality fan, use a big fan and speed control it down. use insulated ducting and a couple of bends between the fan and the inlet and outlet. Look at using an acoustic silencer. It is easy enough to make a fan system so you can't hear it. It takes space, time and some money - and attention to detail. Geoff -- "Peace through superior firepower" "How to build a rolling road dyno", Radar detector FAQ and Forte Agent automation FAQ both at
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Reply to
geoff m
This was the only one that met other specs of the problem. In any case, I did notice the sound rating. I did try it out at the store in their bench display. I shut off all of the other fans and tried this one by itself. It was noticeable, but not "loud". Some of the others were barely audible. Again, I think this is due to the fact that they are allowing the motors to cavitate the air and have very little "air noise".
The "other" fans with sonnes ratings of around 2 also had cfm's of about 40 and cost 5x what this one did. What exactly is a sonne? I am aware of dB for rating sound, but don't know what sort of unit a sonne is.
Reply to
Jeridiah
I built an air tight super insulated house, and needed my bathroom fan on all night for air exchange [I know, I never got around to building the heat exchangers because we started having kids.]. I had the super quiet mode fan, but I wanted lower flow and even lower noise. I got a dimmer switch that was rated for motors. That way I could dial in the noise and air flow I wanted.
Reply to
Clark Magnuson
On Mon, 12 Jul 2004 21:09:55 -0700, Larry Jaques vaguely proposed a theory ......and in reply I say!:
remove ns from my header address to reply via email Missed the OP. Possibly KF'd the poster?
Swap it for the lavatory fan. I have always felt that the lavatory fan has far more value for noise than for extraction.
Reply to
Old Nick
On 13 Jul 2004 06:00:28 -0700, snipped-for-privacy@yahoo.com (Jeridiah) calmly ranted:
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Reply to
Larry Jaques
Where would I find such a thing? Hadn't been considered, but now maybe.
For the record, the fan has been doing an awesome job of cooling the house "naturally", the inside vs outside temp "feel" is easily 10 degrees. Haven't found a thermometer to check the difference, but it is worth the effect, it is just a matter of making the noise less.
JW
Reply to
Jeridiah
why do bathroom fans always come on with the light switch, when they are most useful after the light goes out?
Reply to
Jon Grimm
On 14 Jul 2004 14:23:21 -0700, snipped-for-privacy@yahoo.com (Jeridiah) calmly ranted:
Think "greenhouse parts" and Google it.
Add an ess of carpeted tube/box channels to the intake. That should tone it down considerably for a very few dollars.
Next time go to several stores to find a cheaper, quieter fan, eh? ;)
--- Annoy a politician: Be trustworthy, faithful, and honest! ---
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Reply to
Larry Jaques

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