[KennyBlanken]

It's easy to add "legs" to the C-R device - a few dollars at most in wood dowels and no tools, for example. Maximizing filter area is really important because flow vs static pressure for a fan like this is usually logarithmic...and static pressure rapidly rises as the filters get used (their efficiency goes up, but flow drops.) That's one reason you see a lot of squirrel fans used in air filtration units; they can generate much more static pressure.

In theory, if you mounted it fan-down and placed some towel or blankets underneath, you could also dampen a fair amount of the noise coming from the fan.

It's probably more effective and cheaper to get thicker filters. A 20x20x5 filter has five times the filter surface area of a 20x20x1 filter, but costs $36 - about 2-3x as much as a 20x20x1. Two 20x20x5 filters would provide twice the filter surface area.

But...these solutions were all intended mostly for emergency situations where purpose-built air filtration units were in really constrained supply. Folks should really just buy a regular air filtration unit that uses much less electricity and is quieter, especially if it auto-adjusts speed depending upon need.

[jefftk]

> Folks should really just buy a regular air filtration unit that uses much less electricity and is quieter

This post is about how one of these made with a ceiling fan can be much quieter than a regular air filtration unit: "Testing my prototype, it has a CADR of ~180 CFM and is only 33dB. By contrast, the Wirecutter's top-recommended air purifier has a CADR of 233 CFM at 54 dB or 110 CFM at 36 dB. With some tweaks it should be able to match the commercial purifier's performance, without being louder."

> especially if it auto-adjusts speed depending upon need

I see how that works for wildfire smoke, but how would it work for covid?

[mistrial9]

virus in the air is dependent on effective filtration, rather than bulky particulate matter by volume.. the virus is highly contagious (few particles matter a lot)