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Bathroom Exhaust Fan

Posted by mattyp (My Page) on
Thu, Apr 25, 13 at 13:27


I have a small bath - 5'x7' and want to install an exhaust fan. I know I only need about 37 CFM for the size of the bathroom but was wondering if it's bad to go to an 80CFM exhasut fan. I am looking at a panasonic fan and have been reading reviews for the 50CFM WhisperFit. Some people are complaing that it isn't strong enough for their 5x8 bathroom.

Is it bad to oversize the exhasut fan?

thanks for any help!

Follow-Up Postings:

RE: Bathroom Exhaust Fan

I hope not! I wanted a round fan that was sufficienty loud to make guests comfortable. I have a 100 CFM 3.5 sone fan waiting for install in our almost 6x6 powder room.

I don't think it will be a problem, just means the air will change out faster. Plus it's only on for a few minutes at a time in many cases.

I hope someone that has an actual answer replies!

RE: Bathroom Exhaust Fan

My understanding is that if it is too large it will suck the heat out as well in winter. Or the A/c out in the summer...

Just not sure what too big is...

RE: Bathroom Exhaust Fan

The most important thing to suck out is the moisture. The bit of heat or cooling that escapes can be sacrificed as far as I'm concerned because of the need for moisture control. I have an over sized fan in my new remodel and it is working just fine. I think it is a 110cfm and the space dictated a smaller fan if I remember.

RE: Bathroom Exhaust Fan

How big is the space for th 110 fan?

RE: Bathroom Exhaust Fan

Hi, I just looked and my fan is actually 150cfm. My room is 9.5x6.5'. So by convention I could use a 50cfm. But I think that is too small. The 150 works great for me.

I also looked online and saw this site that talks about sizing a room for fans. The article talks about several aspects of a bathroom that need venting. If the room is small or large things differ in sizing it seems. I linked the article below.

Here is a link that might be useful: fans-how to size a bathroom...

RE: Bathroom Exhaust Fan

thanks! Now I'm thinkg the 80 CFM fan I wanted to get could be too small...

RE: Bathroom Exhaust Fan

I think it may be large for the bathroom.

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