Woodworking Tip: Box Fan Filter " I made a cheap air cleaner for dust in my shop by attaching a furnace filter to a box fan. I just set the fan on my workbench whenever I’m sanding. It works so well that I decided to make a more permanent air cleaner. I mounted the fan overhead, attaching it to the floor joists in my shop, see drawing."
Gotta check this one out...Solutions - PreVent AC Filter Improve your air conditioner’s efficiency up to 21%! Lower your utility bills by wrapping the PreVent Air Conditioner Filter around your central AC unit! The fine-mesh material is designed to keep out dust, bugs, pollen and other airborne debris that clog your AC’s motor and hinder its efficiency.