I am having problems with my upstairs bathroom ventilation fan during showers. The house is 8 years old and originally came with a 50 CFM fan. We were having problems with moisture on the walls/mirror with the OEM fan, so we switched to an 80 CFM fan, but to no avail, still moisture on the walls and mirror. Problem now is starting to show mildew and mold on wood trim around shower. The bathroom is only 8' x 5' x 8', so 50 CFM should pull the moisture out, but it did not do the job, hence the change. We are having no problems with moisture in our master bathroom, which is right next to problem bathroom.
Any suggestions on what to look for or change with the ventilation fan?