Whatever you see in these reviews, they are ridiculous to believe. I checked the static pressure on the filter in my duct system and the drop across the filter was only 0.1 inch. It's phenomenal! This Merv 11 filter is safe to use in all HVAC systems as long as you pull it out every 10 fans. Let it run for days and wash thoroughly. Whatever the guy says about his static pressure, well his duct system can't handle the filters. I have 2-16" returns with 20x20 filter rods installed and YOU SHOULD HAVE A GREAT RETURN, THIS WILL NOT WORK FOR YOU. My static pressure was no higher than my Merv 3 filters, actually better with k&n filters.
Filter under the sink Aquaphor Favorit ECO silver
20 Review
NANPU Compressed Air Filter Regulator Combo: Brass Element, Semi-Auto Drain, 0-150 Psi Gauge, And More
21 Review
NANPU 3/8" NPT Compressed Air Filter Regulator Combo Piggyback, 5 Micron Brass Element, Poly Bowl, Semi-Auto Drain, Metal Bracket, 0-150 Psi Gauge
26 Review
NANPU 1 FRL Air Filter Regulator Lubricator Combo With 0-150 Psi Gauge, 5 Micron Brass Element, Poly Bowl & Semi-Auto Drain - Metal Bracket Included
20 Review