Reddit reviews 12" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Face/Door - HVAC Duct Cover - Flat Stamped Face -White [Outer Dimensions: 13.75w X 13.75h]
We found 3 Reddit comments about 12" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Face/Door - HVAC Duct Cover - Flat Stamped Face -White [Outer Dimensions: 13.75w X 13.75h]. Here are the top ones, ranked by their Reddit score.
Beautiful and SturdyHigh Quality Solid Stamped steel and No Sharp EdgesOur Filter Grille Latch is Easy To Use On Your Fingers And Requires No Screwdriver To Open.Removable Door/Face For Easy Filter Change & Cleaning - Uses a 1" Thick FilterPowder-Coat Finish - Smooth, Shiny, Scratch-Resistant, Beautiful. Looks Like It Was Just Waxed
I went the basement route, in a storage closet.
I put an exhaust vent in the wall with two 12v 140mm Noctua fans, found an AC vent grill at Lowes that they fit perfectly into. Those particular fans blow a TON of air and are pretty quiet.
Then I put a filtered intake vent into the bottom of the door.
The exhaust fans create a vacuum inside the closet and suck air in through the intake. It keeps the closet at the exact same temperature as the rest of the basement.
edit - grammar
Good point on the positive pressure.
That sounds like a good design. If looks aren't important, you could adapt something like ...
https://www.amazon.com/Steel-Return-Air-Filter-Grille/dp/B0061MI4ZY
... and use pleated house filters.
12" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Face/Door - HVAC DUCT COVER - Flat" Stamped Face - White [Outer Dimensions: 14.5 X 13.75] https://www.amazon.com/dp/B0061MI4ZY/ref=cm_sw_r_cp_apa_i_ysCpDb08XVTK9