Baluster Air Filter Box Conversion

I have used 20" air filters taped to the back of a box fan for years to create a simple air purifier for various rooms in our house. However, this placed extra strain on the motor and meant the fan was pointing horizontally, which was not ideal in colder weather.

I took four leftover balusters from repairing my deck and cut them down to 20" and then screwed eight of these caps onto the ends. The filters (I use MERV 11) slide into the grooves. It does hold together and have a good seal without any tape, but I recommend a small piece of packing tape in the seam between each of the filters for a better seal and to make it easier to move. Lay the fan on top and tape it into place with a small piece on each side.

This design sits on the floor and has run for over a month straight with excellent results. The fan is no longer straining since the surface area is greatly increased and points straight up so no one is in the flow path. I replaced the first set of filters after a month but I plan to run this next batch longer to see how they hold up. Once I use these up I plan to increase the MERV rating for pollen season. I also want to modify the design to allow for small bungees to be attached so that you don't need tape for the corners or to hold the fan in place.

I printed samples on both the Prusa Mini and the Prusa MK4 with great results. I designed it to be easy to print, so no supports are needed and it prints fine on both the structural and speed profiles.

Print Settings

• Filament: PLA
• Layer Height: 0.2mm
• Perimeters: 3