Building a Better DIY Purifier

There are a lot of ways you can upgrade the air quality in your home–our knowledge base is filled with them! However, and this is key for many types of emergency preparedness, you should have an air-filtering purifier, or have the materials for a DIY purifier. You’ve seen them–the filters that you tape into a four-sided box that you then tape to a 20” box fan (Corsi-Rosenthal box). They do work great. Do they look great? Eh, not so much. Can you change the filter(s) easily? Again, no. For me, just using duct tape on anything I want to re-use is a non-starter. The adhesive is too goopy and literally stinks (the adhesive has VOCs). I found that other people are thinking the same way.
Enter an Etsy entrepreneur who has done a lot of homework: “The 3D Handyman” from St. Louis, Missouri. He isn’t just a guy with an invention looking to turn a couple bucks profit. He really has spent over 300 hours testing his DIY purifiers with all kinds of off-the shelf filters to see which ones removed smoke (incense sticks) most efficiently, and even compared them to HEPA filters on the retail market like Levoit, Blue Air and Honeywell. Why? Because if you’re going to build a DIY filter with a box fan, why not get the most filter for your dollar, and make it look decent to boot. He didn’t just stop at box fan units, though. Being a DIY renovator too, he wanted filters that could handle wood dust, cement dust, etc.
Like The 3D Handyman, we tend to agree that thicker filters give you more bang for your buck. They are more expensive, but they have the surface area to operate longer than the thinner ones. This video by Spencer Olinger showcases a really good value, NordicPure 20x20x5” filter (looks like it might have activated carbon too).
Next up, The Healthy Home Guide upgrades looks AND sound by using an AC Infinity fan in place of the standard 20” box fan. He lists the many advantages to his design:
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It’s quieter for the same air delivery rate (CFM)
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It takes up less floor space
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It doesn’t release VOCs of its own because it uses hot glue, not tape
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It looks better
What if the skies are filling with smoke from a wildfire and the local hardware store has sold out of all of the filters? Maker DIY found a way to build an air purifier from a 5 gallon bucket, HEPA vacuum filter bag, a bathroom fan and some miscellaneous tools. I guess everyone else forgot that HEPA vacuum cleaners have really useful bag filters!
If you’re looking for an easy DIY filter for your shop, Matt Montavan found a powerful fan and cylindrical filter that have the same diameter, and are easily attached. He also shows how to easily make removable casters for moving it around the shop, and how to clean it out (leaf blower outside!).
There are also several easy ways to upgrade a box fan into an air purifier on Amazon. Lasko, a trusted fan brand, markets a steel-body 20” box fan with a removable grille to hold any 20x20x1” filter. One MERV10 filter is included, however, you could get a supply of MERV13 filters in case of emergencies.
Finally, there are clips to convert your 20” box fan more easily into an air purifier. Although some users say the clips fit great and that tape is no longer needed, clips alone don’t provide the airtight seal that tape does. We just recommend that you measure your box fan accordingly before ordering, and maybe grab some wide painters tape for backup. For sure, there’s always someone looking to build a better mousetrap, or should we say, hack that mousetrap!
Photo by Marcus Kauffman on Unsplash