jeffreyg, he said 12 foot ceiling in a subsequent post, so 7 x 30 x 12 feet = 2520 cubic feet. I don't think any of the Panasonic bathroom fans will be effective for a room that size. I would probably consult an HVAC person in my area, but probably something like this Doran Pro-lab SL/PS Darkroom Exhaust Fan would do the trick for a room that size. It's not that much more expensive than a Panasonic 150 CFM fan.