DIY Air Filter

There is an easy and cost effective way to make a filter fan to clean the air in your home. These fan units filter fine particles and black carbon, which are common during wildfire or wood smoke events and can cause health impacts.

We have tested the performance of these filter fans and they dramatically reduce fine particles and black carbon from the air. See the graph below that shows an example of the filter fan performance. 


Supplies you need:

  • 20" x 20" box fan
  • 20" x 20" x 1" MERV 13 or FPR 10 filter 
  • Power drill*
  • 3/4" screws*
  • 2" corner brackets*

* If you do not have access to a power drill, you can simply use any kind of tape instead of screws and brackets.

All supplies can be found at home improvement or hardware stores.

See the video tutorial on how to build a filter fan yourself:

The video was made possible by the students from RecTech, an internship program with Seattle Parks and Recreation. RecTech’s mission is to remove barriers and train students through technology to better prepare them for college. 

Important Tips While Installing Filter to the Fan: 

  • Make sure the filter is placed against the back of the fan.
  • Make sure the arrows on the filter point towards the front of the fan or follow the same air flow of the fan.

 Important Tips While Using Fan:  

  • Use the fan for at least 10-15 minutes when needed, can be longer.
  • Close all windows and doors while fan is in use (it won’t help if windows are wide open).
  • Better to use in the room that you are in at that time.
  • Position the fan toward the middle of the room, away from walls and big objects.
  • Turn off filter fan when you leave the room. 
  • Do not use while sleeping or not at home. 
  • Replace filters every 3 months or when they look dirty/dark (this depends on how frequently the unit is used).