Today, I was asked about effective air cleaners, because wildfires have already begun to flare in North America.
Extensive global testing has found that a DIY #CorsiRosenthalBox will outperform almost every commercial HEPA unit while costing less to run.
For the US & Canada, the best source of filters to build one is Costco: Filtrete 1900, 2200, or 2500 models with at least one 20-inch dimension.
These units also help mitigate allergens and infectious aerosols like #Covid and Influenza.
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A quieter alternative to the traditional box fan for a #CorsiRosenthalBox is to mount 5 or 6 Arctic P14 PST computer fans under a piece of cardboard/foam core/poster board instead. (They come in 5-packs.)
It can increase the initial cost a bit, but I feel the ability to comfortably run the unit 24/7 makes up for it.
To power the fans, you need a 12v fan power supply like this:
https://www.amazon.com/dp/B0BBSBV9CF
Mounting screws should be #6-32 x 1-3/4" with #6-32 hex nuts and optional #6 washers.
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If you want to cover the PC fans to keep little fingers or paws safe, you can use PC fan grills, baking tray grills/cooling racks, or gutter guard mesh.
Also, I recommend getting the tallest filters you can, 20"x25"x1" or 20"x30"x1", because the greater the filter area is, the longer they last and the less they restrict the fans' airflow. At Costco, they're even the same price as the smaller 20"x20"x1".
PS: painter's tape works as well as duct tape while being less sticky to work with.
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PPS: if you're in the US or Canada, the least expensive source for the Arctic P14 PST 5-pack is Amazon:
https://www.amazon.com/dp/B07HC782D5/
It's cheaper for Canadians to order from that link and pay the additional shipping fees than to order them anywhere I've found in Canada. Same is true of the 12v fan power supply linked upthread.
Costco.ca has the Filtrete 2200 in a 4-pack, Costco.com has the Filtrete 2500 4-pack, and neither site requires a membership to order them online.
With a box fan, the cardboard box it comes in is already a perfect size to use one face as the floor of a #CorsiRosenthalBox and the other face as the fan shroud.
For the PC fan version, you can use the manufacturer's cardboard box that the Costco 4-pack of Filtrete filters ships in the same way - one face gets cut to size for the floor, and the other face gets cut to the same size for the top but with holes added where you mount the PC fans. You could maybe double the top for more rigidity.
For a non-DIY, professional looking, and flat-packable air cleaner that's great for both travel and stationary usage, here's the $150 AirFanta 3Pro:
https://amazon.com/dp/B0CJTYWQBT
It's capable of box fan amounts of clean air delivery at much lower sound levels, and it takes up less space while being just as good against smoke and viruses.
Also, it's perfect for folks who don't want to deal with taping all the edges together or who want something that looks more like a product and less like a project.
@kumakaori74 In that case, there's always the CleanAirKits 6 fan plate:
https://www.cleanairkits.com/products/brisk-box?variant=47660329173292
You can pair it with a 4-pack of 16"x25" Filtrete 2500 filters to make a more traditional CR Box:
https://www.costco.com/3m-2500-series-filtrete-1-filter-4-pack.product.4000181409.html
It still requires taping the edges, but the fan plate makes an excellent replacement for a box fan, as it's much quieter. With white tape, the whole thing looks pretty nice and cohesive - still less experimental looking than with silver duct tape.
Texan_Reverend
Kuma74 (he/him)