I'm building a bathroom that's about 80 square feet and I'm looking at exhaust fans. There are cheap ($20-$40) 80 cfm models, mid-priced ($50-$75) fans of 80-180 cfm, and a quiet Broan L300 (I think that was the number) that moves 300 cfm for about $130. I'd like a good-quality, quiet fan that moves some air and I don't want a built-in light.
This fan will have to exhaust through horizontal ducting for about 18 feet because this bathroom is on a lower level in the middle of my house.
Is 300 cfm big-time overkill? Will I introduce difficulties with supplying air to the bathroom when the door is closed to keep up with the exhaust volume?