I am intrigued by the rave reviews the Panasonic bathroom fans get, and would consider trying one out. I wonder about the install, though. I have not done this before except to replace one fan with another of equal and that was in a different bath. My current fan in this bath is something like 7x7 and it looks like the Pannys are about twice that size. I have never looked at the top side of the current fan, but I know it is way over at the edge of the roof with a lot of blown in insulation between the door to the attic and the fan, so working there might be hard. And, I don't know how these fans are attached... would it be unrealistic to expect that there is room up there to replace a 7x7 fan with one that is 13 x 13? Thanks.