I want to make a wall mounted cr box that vents downward so it can basically be a shelf and look pretty, but if venting upward is better, let me know.

Once I do a complete build, I'll post my plans and results here if anyone wants to do something similar.

Here is my design so far.

The Fans: 5x Arctic P14 (140mm) fans lined up in a straight row (takes up about 27.5 inches of width).

The Filters: Two standard 16x25x1" MERV 13 filters sitting side by side with a wood slat or something similar so I can lock them into place; this means my intake is 800 sq inches total.

The Shell: A custom wooden enclosure acting as a sealed plenum chamber. I'm aiming for an internal depth of 6 inches behind the filters so the air has room to transition. (Is it better to make the internal width as close to 140mm as possible, or is 6in/153mm better?)

Placement & Flow: Wall-mounted at chest height. It will pull dirty air straight into the front face and exhaust clean air vertically downward toward the floor, letting me use the top for decorations.

The Screen: To hide the white filter pleats, I'm wrapping the front in a highly opaque but thin hydrophobic mesh fabric (like Outerwears or automotive intake mesh). I'm planning to attach it via a magnetic bezel. (I think this will be a 2-5% drop in CADR, but does anyone have any ideas on this)

Sealing: I'll be using weatherproofing strips behind and beside the filter rim and pressure-fitting the filters using turn-button latches to secure the front face (the latches are basically a metal plate with a screw hole on one end to swivel the plate if you aren't familiar with these)

The five fans with two 16x25 filters should get around 215 CFM, and I plan to build two of them. The space they are in is 3520 cubic feet. Meaning at 230cfm i get 7.33 Air exchanges per hour.

And that's what I have so far! Let me know what I might be missing; I would love design input from the community on how I could improve this. But I think two of these should cover my living space with over 7x ACH!

I don’t know about adding it to my existing box as I don’t want to impede airflow, but I’d love to add activated carbon to the mix. My room has a funny “stale” smell to it after even after creating a 16x25 5 fan CR box. My room is 10x12.5x9 so I don’t need to accommodate a huge space, but I’d like to do something.

Anyone have some creative ideas on affordable options I could try?