re: Corsi-Rosenthal Air Filter Box

I saw some examples of filter boxes where they used HVAC (squirrel cage) blowers but none that did any sort of analysis about how quickly or well they filtered the air.  The closest that I have seen is from YouTuber Jay Bates where he made a cart using HVAC filters and and an HVAC blower.  He was happy with the performance.  I went back and forth about using an HVAC blower but when I saw the simplicity of the C-R filter approach where you can literally buy everything you need for under $100 at a Home Depot, I decided to finally give this a try.  One nice thing about it is that it will be much lighter so will be easier to hang from the ceiling than one that requires a plywood box.  

As far as the Grizzly filter is concerned,curious about how its surface area compares to a 4" MERV 13 or 14 HVAC filter.   The 4"  MERV 13 filters I bought from FilterBuy have about 2800 square inches per filter and I will have at least 4 of them one I make one that I can hang from the ceiling.   It would be nice if Grizzly or the other similar brands listed a MERV rating.  They just call the inner filter a 1 micron filter but do not say how efficient or effective it is at filtering 1 micron particles.  If you look at the MERV chart I posted above, a MERV 11 filter technically filters some 1 micron particles, just not very well.   It would be nice to find out what what the Grizzly's MERV rating is.  As you can see from my update above, my Wen actually work fairly well and uses a filter that is similar but smaller than the Grizzly one  so I would expect your results will be good as well.  Let us know what you find with your tests.