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Bathroom ventilation

I have a steam/moisture ventilation problem. When I got the house, I noticed that the original bathroom vent was not properly vented outside. Instead, it put all the hot moist air into the attic. I knew that I had to change that. I did, but I am still retaining a lot of moisture in the bathroom.
Here is the set up I have: My bathroom is about 9’ long and 5.5’ wide. The shower is located in the first half of the bathroom, followed by the toilet and the sink at the end. I wanted to make sure that all the moisture properly leaves the bathroom, so I went to Home depot and purchased the biggest vent I could find (140CFMs) and since I live in the Northeast, I got the insulated venting pipe and all the necessary parts to direct the hot moist air out through the roof. The vent is located approximately in the center of the bathroom, (just past the shower) so the ductwork is only about 4-5’ and it is horizontal. The vent assembly is large. It occupies all of the space allowed by the ceiling rafters (12’ x 8.5”), so I don’t think I could have installed anything larger. Although the vent is rated at 140 CFM, it does not evacuate all of the moisture from the bathroom.
I have two problems. When taking a hot shower the moist air accumulates on one half of my ceiling. The ceiling is split into two areas: area one (with water condensation) is next to the shower and before the vent, and second area (dry) is everything past the vent. My second problem is that water is condensing on the cold metal parts of the vent and dripping on my floor.
My attic is fully insulated (up to R30) as I just blew cellulose insulation in preparation for the winter.
What do you suggest I could do to get rid of the moisture?
I suppose when it gets cold enough to turn the heat on, my bathroom radiator will help a little. But it is located at the end of the bathroom (under the dry area of the ceiling), so I doubt that it will make much difference. Do you think that a heat lamp at the entrance to the bathroom may help? Also, is there a way to keep the vent parts warm? The manufacturer suggests keeping insulation at least 3’’ away from the vent. Can I lay Styrofoam insulation around the vent?

Thank you for all your suggestions

Re: Bathroom ventilation

Here's a previous thread that may be helpful.


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