If you have an appropriately sized filter holder, I would just install a MERV 13 or 16 filter. They’re very cost effective, widely available, and they will remo

If you have an appropriately sized filter holder, I would just install a MERV 13 or 16 filter. They’re very cost effective, widely available, and they will remove non-living crud, too. The main problem is that many central air systems use crappy thin filter holders. A good low-resistance filter needs a lot of area, and a 4” or 5” thick format works well, 2” is marginal, and 1” sucks. A good filter holder costs under $200, takes very little effort to install in a new system, and is an incredible pain to retrofit into an existing system. And good filters are essentially unsupported in ductless systems.