#cr box

Just swapped out the filters on our 1st Corsi-Rosenthal cube, and what a difference! Dusty old filter above, minty fresh one below.

This particular filter box spent 10+ months on low inside our house, catching tons of wildfire smoke, PM2.5, and COVID-19 aerosols, as well as pollen, dust, and mold. Glad all that's on THERE and not in our lungs!

I highly recommend building your own CR box for your home, school, work, mutual aid meet ups, etc. All you need is 4 MERV-13 filters (sold at most hardware stores), a 20" box fan, scissors, cardboard, and duct tape.

A new one costs about $75-100 - much cheaper and performs a lot better than a lot of fancy air purifiers. Building it with 2 people takes about an hour (mostly to measure and cut out the weird shroud thing), and swapping in new filters is much faster.

The tune is based, with permission, on “How To Build A Fence” by Nova Scotia singer/songwriter Bob Snider.

How To Build A Corsi-Rosenthal Box

It’s time to clear the air Cause COVID is still there… And if you want a cheap machine that will cancel tox- -ic pathogens in the air, Well then you oughta hear ‘bout the Corsi-Rosenthal Box.

First you get your fan, Keep the box that it came in You’ll need it for the floor; Now get filters, count 'em, four. What rating? MERV-13. The hardware store will know what you mean. As always, you’ll be stuck, Without your tape for duck. Now add a box-cutter, you're on your way to warding off the pox! This is everything you need to build a Corsi-Rosenthal Box.

With the filters, build the shell In order to build it well Look for the big arrow; It shows how the air should flow. First filter you begin With the arrow pointing in Then build a filter fence By butting up against Tape it up so every filter interlocks Now you’ve got four strong walls for your Corsi-Rosenthal Box.

Don’t worry there’s not much more But you’ve got to make a floor That shouldn’t come as a shock Since that’s why you kept the box So cut your square to fit Tape it on the top of it Turn it upside down and then You’re ready for the fan Now with all you’ve done you’ll find that you’re approx- -imately one or two steps from done your Corsi-Rosenthal box

Before you do the rest, You’ve got to give the fan a test You'll feel like such a jerk, If it turns out not to work, When you’ve used up all that tape To attach it to the crate And covered gaps and slits With tape and cardboard bits

The PC Fan #CorsiRosenthalBox

I'm now a convert. PC fans from now on. I built two PC fan CR boxes and I'm addicted. Using PC fans might be the most important innovation to portable air cleaners since the invention of the original CR box. These are unbelievably quiet.

all the good people over on #COVIDisAirborne twitter experimenting with Corsi-Rosenthal box builds w/ different fans and filters and testing their efficiency and posting lists of all the materials they used and DIY videos!! they are saving my life fr.

if you've never heard of a CR box: basically it's a cheaper (and often better) DIY version of a HEPA air filter, which can cost several hundred dollars. The purpose of a CR box is to filter viruses, wildfire smoke, pollen, and other harmful particles out of the air, and provide clean air in exchange.

Your average CR box is made out of a box fan + air filters/furnace filters + duct tape. comparatively really cheap to build; I did mine for about $90 ($35 box fan + 5 Honeywell MERV 13 20x20x1 filters + duct tape) (4 filters for the build itself + an extra in case of damage).

Here's an article w/ links to videos and other articles on how to build a basic one out of a box fan + 4 filters.

If you don't have the space in your home for a full-size one, you can use PC fans + 2-3 filters for a slimmer box form!! I'm currently gathering materials to make this guy so I can replace the bulky box fan CR build that's currently in my room:

as well as this one for my living room, where I and my roommates spend a lot of time:

If you're really tight on space, you could make an even tinier CR box, which unfortunately filters less air, but is still better than nothin':

anyways. I'm rambling but CR boxes have been proven to help prevent infections if someone in your household comes down w/ covid. They save lives and they're cheap to build. Please consider building one for your home, and/or asking your school or workplace if building some for your common spaces is a possibility!! As I'm working indoors this winter (and no-one masks except for me), I'm planning to ask my boss if they'd be willing to use company funds to build one or two of these.

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TL;DR: Corsi-Rosenthal Boxes deliver quality air filtration at upwards of 30% higher air exchanges than comparable HEPA filters on the market. Build 'em for covid. Build em' for wildfire smoke. Build 'em for allergies. Build 'em to clean the air.

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