Filtrete 20x25x1 HVAC Furnace Air Filter, MPR 1000 MERV 11, Allergen Defense, 6 Pack

Less expensive than the big box hardware store across the street, and delivered to my door. The trick to installing these was taught to me by an HVAC tech: Turn the Fan setting to "On" so there is an active suction and these filters will literally be held in place by the vacume of the fan setting so you can put the grate back in place without everything falling on your head. My filter grate is in the ceiling and it was driving me bananas trying to get these things to stay put (I have a double grate, so I have to install two at a time and not enough hands to hold them in place) while I replace the grate. I never looked to see if there is a tip like that on the package, but if there isn't, now you know. I always order another package when I install the one I previously ordered so that I always have a fresh pair to replace with.

I can tell when we put a fresh one of these in as the unit is in the half stand up crawlspace with GA Red Mold…i mean CLAY! It has a special odor of rot and decay all it's own under there. While the HVAC itself was replaced 2 years ago in the place we rent, the ductwork is 40 years old and is disgusting. At least the air coming ‘through them' is cleaner when using these filters! Without these good quality filters the red mold dirt and rot smell would mix with the aged duct mildew, dust and rust smell. My senses would be truly be offended at that!