Bathroom ventilation. Small bathroom. Steam

Old 04-29-16, 02:02 PM
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Bathroom ventilation. Small bathroom. Steam


I recently bought a house and I have bathroom which is no more then 10x5. When I first moved in they had a 50CFM bath fan and after a shower the bathroom had so much
Steam you could feel your self breathing in. And the paint has visible sweat marks. The mirror is also super fogged up.

I then installed a 140 CfM fan. I upgraded the duct to a 6inch flexible duct that vents out the side of my house.

I feel like when I shower I stil have the same issues. Maybe not to the same extent but the walls still sweat and the mirror still fogs.

I saw a 300 CfM fan but I think that's overkill??? I'm at such a loss here

Is the bathroom just so small that I'll always have this issue

Old 04-29-16, 02:10 PM
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140 CFM should be plenty as that is in theory giving you 20 air changes an hour, whereas normally 8-10 for a bathroom is fine. I suspect there is no source for make up air and that results in the fan moving much less air. Do you leave the door cracked while using the shower? Or is there at least an inch gap at the bottom of the door? If you don't leave the door partially open, try leaving it cracked a couple of inches and see if that helps.

Where is the fan located with respect to the shower?
Old 05-01-16, 08:44 AM
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Thanks for the reply.
The fan is in the center of the room. So probably 1-2 feet away from the shower.

I did leave the door cracked which seemed to help. The mirror is less foggy but still foggy.

Will I just be dealing with this because of it being a small bathroom? Anything I can do to have no moisture in the bathroom and have if all just sucked out the exhaust? Thanks again
Old 05-01-16, 10:26 AM
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Hi jenny. Increasing the exhaust and providing the needed make-up air will help remove the moisture, but reducing the amount of steam you generate will also help. (I know you didn't want to hear that .)

I use a low flow shower head that has a volume control built in. As I shower I can increase or decrease the flow as needed. My objective is to reduce my total hot water consumption, but it also reduces the steam and related problems.

When you are ready ti exit the bathroom, they make switches for the exhaust fans that will keep them running for a preset amount of time, like 15 or 20 minutes, whatever you determine is needed to dry out the bathroom after a shower.

Old 05-02-16, 06:49 AM
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The fan and make up air could be fine. It could be the shower head. I have a head that on one setting makes the water come out in a hard mist. this basically atomizes the water and it fogs up much worse. On other settings no fog at all.

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