Seeking the ultimate quietest window fan

Bimmerboy

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Yes, I'm still on my quest for the pinnacle in silent window fan operation. Thanks to all who responded to my last post asking about safe ways to electrically slow a fan down to make less air noise.
Noise level information is really hard to find. Most manufacturers don't test or publish db levels. Seems only Air King does but they don't make a model I'm really interested in. I even just got off the phone with with the technical dept. at Lakewood Engineering about their products, and they don't know.
So any big time fan experts around here? My questions are:
What kind of fan tends to make less air noise, a larger diameter at slower RPM or smaller diameter at higher RPM (even though the higher RPM smaller one might flow less total CFM) ?
Does a squirrel cage design make less noise than a prop type?
Who knows what the quietest window fan is? I'm specifically interested in the Lasko 1200 or the Lakewood LPRW-3 (there must be at least 3 people on the planet that have one of these fans), but recommendations on any brand is fine. I'm currently using a Bionare BW2300 which is a good fan.
This fan is going to be used in a small recording studio so that's why I'm being so "retentive" about noise. It needs to be near where I sit due to space restriction and layout. It'll be on a lot since I'll be smoking in there. One of the last few places a person can smoke in NY, but I digress.
Whatever I get, it'll be slowed down anyway by an external control module (which means I have to get one with analog controls, not digital), but every factor counts.
 

Lynx_Arc

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larger diameter running slower is usually quieter because high speed small fans tend to whine. If you are really concerned about noise get a squirrel cage blower, mount it in a foam box as a baffle and redirect the air output around a few curves to kill a lot of the sound.
 

sithjedi333

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the cheap $20 ones in your local pharmacy or kmart are pretty quiet when run on low speed. They're about 2 feet in diameter and have a square shape.
 

Bimmerboy

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Thanks for the response so far, guys. Thinking about it this morning has led me to a conclusion.
I'm driving myself nuts! I do this all the time. Analysis paralysis. I'm gonna' buy two fans and A/B them for a comparison. The extra money spent will be worth not spending any more time on this @#$% subject! I can always sell one on EBay in "used only once" condition.
I've now twice posted window fan questions on a flashlight forum. Silly, but goes to show how little info one finds sometimes on this huge, information packed WWW. The people here are a pretty technical bunch so it seemed like the thing to do.
So, one last call out to the CPF community before I whip out the credit card and buy BOTH the Lasko 1200 and the Lakewood LPRW-3. The Lakewood is squirrel cage, and the Lasko is a 12" prop (taller than the average 9" twin fans but is only a single prop which I will slow down with a Variac or X-10).
The response from Lynx_Arc started to get to what I want to know, so last question if anyone knows for sure.
Do squirrel cages tend to make less air noise than a prop?
 

Lurker

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I tend to believe that propellers can be quieter because I am also of the opinion that slower and larger is better than small and fast. I think the cage has to be pretty fast to work. Maybe I have never seen a high-quality cage fan, but all the ones I have seen are noisy. Consider a typical ceiling fan. They can move a lot of air with virtually no noise. That is a propeller type and is very large and relatively slow.

One other consideration will be the screens that the air will move through. There are typically screens on the front and back of a fan and also one in the window. Each one will make noise as air is forced through it. Minimizing the number of screens and increasing their grid size will reduce noise.

One final comment that you may find annoying, so I will apologize in advance. But if you spent your fan money on a quit-smoking system, your wallet and your future health will both thank you and you won't need the fans any more.

Good luck.
 

cobb

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I would suggest making your own. Look at overclockers.com and see the fans info they have and check out bgmicro.com for cheap muffin and other fans, they list noise as well as flow ratings.
 

cobb

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I would suggest making your own. Look at overclockers.com and see the fans info they have and check out bgmicro.com for cheap muffin and other fans, they list noise as well as flow ratings.
 

modamag

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I use Papst fans they're rated at 24db /ubbthreads/images/graemlins/thinking.gif
If that still doesn't work just go with a water cooling.
 

MrMom

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QUOTE lurker: I tend to believe that propellers can be quieter because I am also of the opinion that slower and larger is better than small and fast. I think the cage has to be pretty fast to work. Maybe I have never seen a high-quality cage fan, but all the ones I have seen are noisy. END QUOTE

correct

Cage fans have many small blades that turn at a high RPM producing more noise for a given CFM. In a proper housing they do move the air well.
 

Lynx_Arc

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squirrel cages can be just as noisy a lot depends on the amounts of CFM pushed and size/speed of the rotation. The advantage of them is they are probably easier to make a custom enclosure with baffling to mute the sound they create than muffin fans. I have seen larger blowers that are quieter and smaller ones that whine similarly to muffin fans.
 

cobb

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I have two fans I use on my wheelchair. One is one you get from the auto section of any store taht clips on and uses 12 volts. Man its loud and blows a lot of air out. It has three blades. Ive assumed part of the noise is windage around the fins in the shroud and the motor being driven at full voltage. I have no way to run it on less than 12 volts unless I use cell batteries in series.

The other is one i built from a fan at brmicro. It is a 24 volt 1 amp 300 cfm model. Man, its heavy. I hooked a clamp from a clamp on halogen work lamp and wired it up to a cig plug for my 24 volt side of my wheelchair power supply I made. Actually that is off the batteries directly, I get 12volts from a 24-12 volt converter. Well, when I powered this fan up, it slowly worled up. It has 9 blades. It took about a minute to spool up and man it blew a steady stream of air and made a humming sound. The air flow was like that from a vacuum cleaner with the blow feature. I then unlugged it and man, it kept right on going for three minutes til it spooled down. I then trid it on 12 volts and man, it was almost silent and still blew a good deal of air.
 

Lynx_Arc

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Underdriving fans is a trick most modders use to control noise. You buy a high CFM fan and drive it at 1/3 to 1/2 lower voltage to quiet it down. If you can get a powerful large fan that is DC 12-24v and drive it at 2/3 to 1/2 voltage and put it in a sound insulating box with vibration mounts you should be able to get it considerably quieter. After all a car is a HUGE powerful FAN with a muffler on it if you think about it.
 

James S

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The advantage of a squirrel cage is that it's rarely sitting next to you. if you really need to move air and have it be quiet, then you need to put the fan somewhere else and suck the air through a duct /ubbthreads/images/graemlins/wink.gif maybe not very practical but that is the only way to move air with close to zero noise.
 

Bimmerboy

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You guys are the best!
The ideas and suggestions here helped me reach a decision that should work very nicely. After weighing the options and imagining the end results of each, I'm going to get one fan for now (the Lasko prop) over the web, then when springtime comes around and these things are on the store shelves, I'll do a comparison. It would've saved me X amount of headache if the stores carried them year round.
However, this was nothing compared to my recent futon shopping project. Call it more like a research expedition that would've needed government funding if I got any crazier with it. With the different choices and variations, and really no way to try them out without heading into NYC, I did the analysis paralysis thing for about 4 weeks before getting on the train to the city. Maybe I like self-torture. /ubbthreads/images/graemlins/icon3.gif
On the flip side though, it didn't take long to figure which lights I wanted once I started coming to this place. /ubbthreads/images/graemlins/wink.gif
 
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