But that one costs $400, for that money you can buy a commercial / professional / design filter too. The Corsi-Rosenthal one is <$100.

If volume is a problem, I'm sure one can lower the fan speed below the lowest setting with some electronics knowledge.

It's $230 with just the parts. Filters will cost about $40 for two. So like $270 and it's much quieter than commercial purifiers at a higher CFM.