I have a one year old house on a crawl space that is lined with plastic. The indoor humidity is 60-70%. Have a central heat and air unit outside, gas heat, electric air, ducted through crawl space. I live in TN where it is humid. A Ultra air 90 whole house dehumidifier has been recommended. My concerns are that this will be placed in the crawl space and I am concerned about mold growth on the coils of the unit. Has this been a problem with anyone else? Also, the diagrams for installation show a return from inside the house with what appears to be a grill and filter like a normal return for CHA unit. A person I spoke with said all that was needed was an eight inch opening cut into the floor? But this is not what is shown in the diagrams from Ultra air website? But again I am really concerned about mold growth on the coils of the unit placed in the crawl space. Any help appreciated.