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 f

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.