Bath Fan upgrade

I think he means fan size. As far as replacement fans, most are made to fit the standard opening for vents. There are units without remotes but that puts their controls at the ceiling level which makes them difficult to use for vertically challenged people. Our ceiling is almost 7 feet and 6'4" me has no problem but the other half is 5'1" and cannot reach the vents or fan switch. This may be a no remote killer unless you are all tall.