Holy fuck
This works best if you keep windows closed.
Another design is using 2 20x25x1 filters, taping them to the sides of the box fan and then to each other so they sort of make a triangle, then cutting cardboard to make a top and bottom to the triangle.
This was discovered as a more effective design during the 2020 US west coast fires.
https://tombuildsstuff.blogspot.com/2013/06/better-box-fan-air-purifier.html
A better more efficient and odor eliminating homemade air purifier than just taping a 20x20x1 filter to a box fan. Sometimes you need to
If you live on the west coast of the United States, fire season is coming and this is vital.
We’ve been using one, and they’re great. Might try to make the double filter version this year.
theyve been doing a bunch of studies on this during the pandemic and this design is best! 4 filters and a shroud to optimize flow rate.
Corsi-Rosenthal Cube
https://encycla.com/Corsi-Rosenthal_Cube
I’ve personally used both the flat single-filter version AND the triangular two-filter version, and based on subjective personal experience I would argue that the benefits from the second filter, both in terms of airflow and filtration, are absolutely worth it. If you need a makeshift air filter and you have two filters to work with, build the triangle (if not the box, i have no idea how good that one works but based on the info here i presume it’s a fair bit better.)
This trick works. We use it in my house.
If anyone wants aesthetic inspo or design ideas check R/CrBoxes
