I have two. I agree it's quiet on the lowest speed but it's loud on the medium and high speeds so mine are setup to run 24/7 on the lowest speed regardless of the air quality. The air quality in my house is good and they run nearly always at the low speed anyways. Buy them while they are on sale.

If you’re willing to buy something off the shelf, get one of the IKEA filters. They’re more efficient, quieter, and use less expensive media.

yeah, i get why people were doing the DIY air purifier thing during covid when air purifiers were hard to come by, and the box fan version at least has cost-effectiveness going for it.

but 5x arctic cooling PC fans is ~$100. the commercial versions are easily available, more effective, no more expensive, and don't look like a box of furnace filters taped together.

Huh? 5x Arctic P12 is $24 on Amazon right now, no sale going on. And the whole Corsi-Rosenthal trend started specifically because consumer air purifiers were tested to be both noisier and less effective at their job.

But I'd honestly pay a premium for a commercial air purifier that just has a bunch of 120mm/140mm fan mounts instead of their "maybe tolerable at Very Low" integrated box-fan equivalent.

In general, all I've learned from online reviews of "quiet" appliances is that different people have very different definitions / criteria for "quiet".

conway filter posted above, you can't really hear it from 10ft when it runs on low speed (it has sensor and he autoadjusts ).

i also have iqair which according to reviews is quiet at low speed. in my experience this quiet sounds like airplane (i got it replaced once. apparently it's just the way it is).

I think you're missing his point entirely. The problem with these retail purifiers is that you either get quiet or effective. You don't get both.

Sure, you can't hear it from 10ft away - but how much air is it moving at that setting?

I have various configurations of these PC fan setups and the Arctic P14 Pro that you can get 5 for $32 on amazon are honestly wildly effective and designed for applications with some static pressure (radiators and such).

So we're back to; effective or quiet, you're only going to get both with the PC fans, for now.

I have the one I linked and it is both. Set to auto, it is quiet most of the time and only ramps up when I’m cooking or the air quality is bad.

there is also added benefit of not taking half of the room. i think conway footprint is 1/6th of The Cube if not less.

Rabbit Air (i think they closely related to conway) you can hang on the wall as art piece.