This house was built before bathrooms existed inside homes and this bathroom was remodeled about 21 years ago. I don't know why the contractor didn't put in a vent fan then, but he didn't and I didn't know one was necessary at the time. I've learned a lot about houses since I bought this old thing. There are 3 other bathrooms in the house, new since 21 years ago, which are vented. Originally this was a guest bath and used very seldom, but not the family has grown and this is now a family bathroom and the shower is used quite a bit. This bathroom has all interior walls with no access to the outside through a wall. It is in the center of the house on the first floor underneath a large upper room so there is no wall that runs up to the second floor room next to this bathroom. The laundry room is next to the bathroom and the dryer is vented under the floor via a long pipe that terminates on the outside of the house. Could I put the vent in the floor and run the duct under the house to the outside wall? Could I put the vent in the floor and run the duct to the dryer duct and send air and moisture out that way? Obviously I want to avoid ripping out walls, ceiling and floors for this project. I also don't know who to call to discuss this project with -- electrician, HVAC contractor????? Thanks for any ideas you have. I live in Middle Tennessee about 50 miles from Nashville, 20 miles from Murfreesboro. I'd like to get the bathroom vented before too much damage is done from mold and any thing else that might go wrong.