Thanks for the feedback. Thinking about it some more, a general purpose 1" HVAC filters are rated at about .12 in. water column at 300 feet per minute. If you'r

Thanks for the feedback. Thinking about it some more, a general purpose 1" HVAC filters are rated at about .12 in. water column at 300 feet per minute. If you're running them a lot slower by having 4x-6x area, then I could see that your tests would bear out. I often reference this manufacturer when designing a duct system and selecting filter sizes. This is for their MERV10 filter. MERV8 is lower initial pressure. They have a velocity vs pressure chart on page 4. At 50 FPM it's down to about 0.03 in. w.c. https://www.glasfloss.com/product/zl-hv/ https://www.glasfloss.com/product/zl-hv/ I think a centrifugal could still be an advantage for noise while having a reasonable dimension, but your feedback is sincerely appreciated.