Under-rated bathroom venting fan question

[cherylbg]

My upstairs master bathroom is 137" by 124", or 118 sq. ft., so I think I need to have about 140CFM fan to vent the room. The room has a shower, a bathtub, a couple of sinks, and a toilet.

I have heard a lot of great things about the Panasonic Whisper Warm vent, particularly for people who like to soak in a tub, as it has an inline heater that warms up the room. But it is only rated at 110 CFM.

Am I asking for trouble if I use a 110 CFM fan in this room? Do I need to forego the Whisper Warm, in favour of a 140 CFM fan?

Thanks for the help.
Cheryl

 

[Jimbo]

I like to use a formula for about 8 air changes per hour. 118sq. ft times 8'ceiling = 944 cuft. Times 8 air changes per hour = 7552 cuft per hour. Divide by 60 gives about 125 cuft per minute. I think building codes use 6 changes per hour, which would be about 95 CFM. I do like to be on a higher number. I find it helps with mold issues.

 

[Sponsor]

 

[SteveW]

I can't help with the specifics of your situation, but can add that I have a Panasonic fan, recommended by the handyman that I had put it in. It is one of only a few BR fans that can be mounted vertically, which was one reason I choose it.

Turns out to be a great choice - it is the quietest fan I have ever heard, yet very powerful. It can even pull our bedroom door open due to the suction it creates.

 

[cherylbg]

Thanks, Jimbo - our ceilings are 8' - I can understand wanting 125 CFM, bu the whisper warm only comes in 110 CFM - do you think this would be good enough, if we put it on a 20 or 30 minute timer when we shower?

Thanks for the help.
Cheryl

 

[cherylbg]

Thanks, Steve - Panasonic seems to have a good reputation with their fans.

 

[Jadnashua]

Instead of a timer, you can buy a humidity controlled switch...it will run until the desired humidity level is reached.