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Super cheap DIY air filter to deal with the wildfire smoke.
Smoke from the Canadian wildfires has gotten really bad this year. Luckily, there’s a cheap and readily available way to filter the air in your house.
Pandemic Research to the Rescue
During the pandemic, Engineers Richard Corsi and Jim Rosenthal created a filter design based on cheap 20 inch box fans and common HEPA household air filters to remove virus particles from public spaces. Their design (show ) is excellent, and allows for processing massive amounts of air in public spaces using four air filters. Their design was released to the public to improve health in public spaces like schools that might not have the air flow and filtering to handle pandemic viral loads. The design takes up a lot of space, however.
We built such a box for home use, and noticed a great improvement in everyone’s allergy symptoms. When the filter began to fill up, we went down to a single filter version (pictured), which worked very well and only required changing once every couple of months. It also takes up much less space. Build instructions are listed below.
DIY Corsi-Rosenthal single panel filter:
20 Inch box fan. You may already have one around the house
Aluminum Foil Tape While you could use duct or packing tape, I find the aluminum tape is easier to remove when you need to replace the filter.
Filtrete 1900 or Better Air Filter Get a 20"X20" filter, so it fits directly over the inlet for the box fan. 1900 covers the PM2.5 particle size reported on the air pollution websites. MERV 13 may also be listed on the label, if so — find MERV 14 for better performance. You may want to use better filters if you suffer from respiratory problems.
