Can't beat the Panasonic for quiet. Can barely hear it if you are standing right next to it, and it moves tremendous amount of air through 6 or 8 inch filter. Scrubs room odor free noiselessly, and lasts forever.
soler and palau td 200-silent is the biggest one they make,8 inches.508 or 392 cfm(your choice).have to wire it up your self.very easy,just cut the end of an extension cord to use as a plug.
after 24/7 and two years finally gave out.but so did my vortex.bought a new one.not much more then a vortex.