Comment Comment by kolencherry Yes! This is the basis for the Corsi-Rosenthal Box [1]. Five 20"x20"x1" filters and a box fan, with duct tape to seal the edges. Not the prettiest, but it's effective.[1] https://en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box parent kolencherry 4 years ago
[1] https://en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box