# Why are ceiling fans so quiet? **URL:** \ **Category:** Factual Questions\ **Created:** [February 7, 2016, 5:17am UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388 "2016-02-07T05:17:21Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [February 7, 2016, 5:17am UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/1 "2016-02-07T05:17:21Z")
While exhaust fans are so loud? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [February 7, 2016, 5:31am UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/2 "2016-02-07T05:31:11Z")
Exhaust fans use small blades spinning at high speeds, the opposite of ceiling fans. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [February 7, 2016, 5:35am UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/3 "2016-02-07T05:35:50Z")
Ceiling fans have longer blades which allows them to rotate more slowly. They also have a higher quality motor and are much better balanced. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [February 7, 2016, 5:40am UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/4 "2016-02-07T05:40:41Z")
All depends on design. 5 bladed ceiling fans with longer blades can turn slower to move the same air as a 4 bladed fan and are quieter. They are also prop blades. Exhaust fans have small centrifugal fans running at a higher RPM. 1800 or 3600 RPM normally. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [February 7, 2016, 9:55am UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/5 "2016-02-07T09:55:27Z")
magnetic bearing ceiling fans are not noisy. ---
**Author:** ![Clark\_Cello](https://avatars.discourse-cdn.com/v4/letter/c/58f4c7/32.png) [@Clark\_Cello](https://boards.straightdope.com/u/Clark_Cello)\ **Post date:** [February 7, 2016, 2:46pm UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/6 "2016-02-07T14:46:06Z")
There are two “reasons”. One is the mechanical reason as to why exhaust fans are (usually) louder. The other reason is the utility reason: the reason why the mehanics of the fans are different. These would inlude: [ol] [li]Ceiling fans are meant to be used in large, enclosed (for the most part) areas, and can therefore use large fan blades. Exhaust fans are meant to get air (and mostly stuff in the air) out of their location. This means they need to blow into an exhaust port, which, for reasons of aesthetics, insulation, etc. is usually going to be small. Exhaust fan blades are therefore generally much smaller.[/li][li]Having a noisy exhaust fan is generally not a big deal. They are used temporarily and often in cases, like showering, where there is other noise going on. The noise is either not an issue, or an issue for a short period of time. In other words, there is relatively little incentive to make them silent. Ceiling fans, on the other hand, are used for long periods of time in quiet areas. If they are noisy, they won’t be used, therefore there is incentive to make them very quiet.[/li][/ol] ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [February 7, 2016, 5:18pm UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/7 "2016-02-07T17:18:19Z")
Auxiliary question: why is it that you can buy a low sone bathroom fan (like the ones from Panasonic), but there is no such thing as a low sone microwave exhaust fan? ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [February 8, 2016, 3:19pm UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/8 "2016-02-08T15:19:40Z")
Money. Designing and engineering costs for something that isn’t running too long (as compared to a ceiling fan) would eat up any potential profit. There are some counter top models that are pretty quiet but I suspect your counter space(like mine) is at a premium. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [February 8, 2016, 4:03pm UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/9 "2016-02-08T16:03:47Z")
> [@swampspruce](#): > > Money. Designing and engineering costs for something that isn’t running too long (as compared to a ceiling fan) would eat up any potential profit. There are some counter top models that are pretty quiet but I suspect your counter space(like mine) is at a premium. Yeah, we have a built-in over the stove. I’ve insulated the exhaust duct, which helps a bit. We have quite a bit of counter space, but it’s pretty well occupied. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [February 8, 2016, 4:12pm UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/10 "2016-02-08T16:12:04Z")
> [@Chefguy](#): > > Auxiliary question: why is it that you can buy a low sone bathroom fan (like the ones from Panasonic), but there is no such thing as a low sone microwave exhaust fan? “Sone” I never heard before, but I understand it. This might be an embarrassing fear of misread, but to check: like “the” low sone exhaust fan used in microwave ovens, right? Because maybe microwaves are used in exhaust fans. Do I know? ---
**Author:** ![Hermitian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hermitian/32/470_2.png) [@Hermitian](https://boards.straightdope.com/u/Hermitian)\ **Post date:** [February 8, 2016, 4:20pm UTC](https://boards.straightdope.com/t/why-are-ceiling-fans-so-quiet/745388/11 "2016-02-08T16:20:37Z")
So I assume the OP is asking about bathroom exhaust fans? Or at least that is what I gather from the current responses. As others have mentioned, its all about the requirements. One of my wife’s requirements for getting a new bathroom exhaust fan was that it WAS NOT whisper quiet. Our older house transmitts sounds very well and the last thing she wants is for half the house to hear \*noises \*coming from the bathroom.