Does anyone know whether a bathroom exhaust fan designed to be installed in a ceiling would have any problems if installed in a wall instead? From a mechanical, ball bearings, noise perspective. Not a space perspective.

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    Thanks for the advice. I didn't see any wall mount fans at Home Depot so I wasn't sure if they're really rare and expensive. Sounds like they're not. The one I got was $100 so good quality but I'll probably return it and get a wall mount. Thanks again!
    – jlpp
    Jan 17, 2011 at 16:09

3 Answers 3


In my experience, most decent exhaust fans are dual rated, ceiling or wall. If your fan is described as a ceiling mount only, it is probably one of many inexpensive units that use plastic bushings instead of sealed bearings. If you can easily jiggle the fan blade or squirrel cage axle in it's end bushing mounts, then I probably wouldn't waste my time using it in a wall. If it is a common overall dimension (10"X10") for example and the mechanical connections feel tight and smooth, I might give it a try. Hook some power to it and give it a test run horizontally before you install it. The worse case scenario is that you may have to replace it with a more expensive unit at some future time, which is a very easy job assuming the hole in the wall is the same or smaller than the one you need for your existing unit. The easy answer is to simply spend 50 or 60 bucks and buy a new fan rated for wall mounting. I almost forgot to mention, the orientation of the air back flow preventer is very important. If this flapper will not close by gravity or spring when wall mounted then don't consider using it.


Would it not be better to simply purchase a fan designed to be installed into a wall?

It may well vary from fan to fan but all the ceiling exhaust fans I'm familiar with don't really like being mounted vertically. They are normally designed to correctly load their bearings only when ceiling mounted.

If you do mount them vertically you can expect the bearing to wear faster, which means that although they may not sound louder at first, they will get loader as the wear takes place. In some case the shaft may even rub against the plastic body if gravity is not holding it in the correct running location. Those will definitely be louder, even right from the start.


The bearing and fan should align and run in the same position irrespective of how the fan is mounted. It will align in the opposite direction to which the air is being pushed. The air is being forced out, the fan is being forced in. Newtons 3rd law.

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    While this is true, the question is more concerned with the affect upon the bearings when being operated in an orientation for which they were not designed.
    – Chenmunka
    Jun 29, 2016 at 10:56
  • This is a very bad application of physics. The fact is the physics of a bearing are much more complicated than simple Newtonian, or euclidean understanding of the concepts someone might learn in high school. Bearings have operational standards and limitations, and direction matters greatly as well as the way which forces are applied normally on the bearing (in a fans case being gravity). I don't know heck of a lot about bathroom fans but I do know a lot about bearings. There are thousands of types specifically because of problems like these. Jan 24, 2021 at 20:37

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