I recently stayed in an apartment that didnt have central air so I created a corsi-rosenthal box since the smoke from the Canadian wildfires were so bad.
After 30 days of continuous use, with very minimal periods of it being turned off, this is what the filters look like!
It's disgusting yet also so satisfying to see the filters get darker from debris, dust, and dirt.
Edit: typos
These are great, but if you’re looking for something slightly less bulky, there’s a dude selling kits online using pc fans. I’ve got two and they’re pretty much a CR box in its final form. Kits come with laser cut panels, fans, grates, etc. only need to supply two filters. Way quieter than a box fan. They’re a bit pricey but worth since they can pretty much be placed anywhere.
google clean air kits.
For that money, you can buy actual air filtration units. The box fan may be noisy, but something that big is going to have massive surface area and provide a lot of filtration.
I dont mean airflow as in rate of air moving through the fan, i mean it as in volume of air being filtered.
TIL about the Corsi-Rosenthal Box
It is by far the best air purifier you can get for the money.
I got MERV 13 filters to help with my kids allergies. Inside the house, perfectly fine, but once outside it's sneezing and runny noses. It's amazing.
Been aware of the general idea for a long time, but had no idea that strapping HEPA filters to a fan has a fancy name.
You have to cut some cardboard and use tape too. After when your solution beat every commercial solution you are allowed to name it, just to be able to shame corpo easily.
from huppakke:
Someone posted a link to Wikipedia in the comments, came across their names:
Richard Corsi, an environmental engineer and the incoming Dean of Engineering at the University of California, Davis
Jim Rosenthal, the CEO of filter manufacturer Tex-Air Filters
take what you will from this, but it's definitely not a stick-it-to-the-corp kinda thing
Yeah I was trying a joke. It still beat commercial alternatives which I fell is a Second good reason to give it a name.
"Corsi-Rosenthal Box" sounds like it's some theoretical physics thought experiment, but no it's some filters and a box fan.
Be tempted to build one of those for my shop.
I'm going to start talking in vague terms about my own designs for a "Corsi-Rosenthal Box" when I want to sound smart.
It'll be great if anyone bothers to look it up.
I mean, it sounds like an Einstein-Rosen bridge.
I thought it was for filtering weed smoke, designed by the famous grower and strain creator Ed Rosenthal.
Think it was a covid thing.
No word on ed being the rosenthal in question.
Someone posted a link to Wikipedia in the comments, came across their names:
Richard Corsi, an environmental engineer and the incoming Dean of Engineering at the University of California, Davis
Jim Rosenthal, the CEO of filter manufacturer Tex-Air Filters
These have been around for a long time as DIY filters for folks, I remember seeing one of these on Reddit before comments were a thing.
Once upon a time Reddit drove you to interact with other websites instead of shitposting your best hot take about the title of the post someone else didn’t even visit.
Comments truly ruined Reddit
Now imagine that, but in your lungs. Yikes.
lungs are self cleaning, dirt just dosent stay in there it gets pushed out again by tiny moving hairs
I totally did not realize how much real science was behind these things. I mean this design is so simple and obvious, it seems like something I would throw together because it just looks like it “should” work. And according to the research I just read they are very efficient and effective. Super cool!!!
This is a great reminder to clean my computer fans.
I'm just amazed it apparently took two people to think of taping 4 air filters together with a fan on top.
Curious why it's not 5 filters with some little toilet paper tubes or something for legs. Was it found that the fifth filter is diminishing returns?
Sounds like an argument that would take at least two meetings and a dozen emails if this were done by a company lol.
They may not have been the ones who first thought of it, but the first people to publish research that shows that taping 4 air filters together with a fan works decently compared to other, non-DIY filters (where "worked decently" means does a good enough job that it's worth doing if you want a filter but can't/won't buy or build a more complex filtering system, even if it isn't as good as "proper" filtering systems)
(Tangent: I'm reminded of the "Cox-Zucker machine", a random maths thing that Cox and Zucker made together because when Cox and Zucker met at university, they realised that their names, when combined in the traditional, alphabetical order, sounded "delightfully obscene". )
make sure you get merv 13 or higher for smoke. the filters get gross fast even with 8 but you can tell the difference when you breathe.
I have 2 to 4 of these going at all times and the 8s are full time and 13+ are periodic unless fire season.
Hey, I have that same rug
It really ties the room together
I have the same box fan
i have the same duct tape
Will all of you get out of my house?!?!
Nope, the air is good here. Have any beer?
I saw a couple left in the fridge. Will you grab more chips while you're up, please?
Those start out white?? I think it's time to replace mine.
Christ i wish we could get these filters in au at non-arserapey prices
Post a new one for comparison.
Filtering can be a rabbit hole.
Yes it can!
I was a little miffed when i went to buy the goods for this box because i couldn't get MERV 14 filters and had to settle for MERV 13.
I plan to make a frame so i can just slide filters in each side with the fan mounted on top. I'll have to figure out a means to create a nice seal between the frame and filters so the air passes through instead of around.
Flexible weather stripping for doors is good for this.
This is for strictly mildly interesting material. If it's too interesting, it doesn't belong. If it's not interesting, it doesn't belong.
This is obviously an objective criteria, so the mods are always right. Or maybe mildly right? Ahh.. what do we know?
Just post some stuff and don't spam.