I have a room that is approx 11X12 and need to figure out two things. 1. How many CFM's do I need? I have the choice of 1080cfm, 780cf,, and 440 cfm. 2. How loud are these fans? The bedroom is on the front corner of the house. Will people hear it outside? If someone is standing in the hallway, will they hear it through the door and walls? Thanks, I appreciate the help.