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
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.
Do you know how much power it uses?
Techingredients just did a video on ceiling fan designs and realized that DC motors are vastly more efficient.
They also figured the cost savings to pay for the motor change, and it didn’t take long to pay off.
I looked up a 20 inch box fan on Amazon and it was rated for 67 watts. I ran it almost 24 hrs a day(kids loved to mess with it) and didn’t notice it on my bill.
67 watts is 1.608 kilowatt hours per day. In California (one of the more expensive states for electricity), electricity costs $0.31/kwh. That would come to just under $0.50/day or $15/month.
Watts per hour isn’t a thing. Watts is already a measurement of rate. 67 watts, running for 24 hours, is 1.608 kilowatt-hours.
The rest of your math checks out, assuming no hidden “distribution” or “transmission” fees (like I have).
Thanks for the clarification. Fixed.
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.
Could use those circular filters stacked on each other and a fan at the top. Name it my column.
Didgeridoo air filter is also tempting me now.
Dongderidong air filter ?
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.
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
… mostly into your stomach.
I have great news for you about what happens to the contents of the stomach!
It also gets pushed out! (Normally)
dont worry they mix with the microplastics down there
Some dirt gets pushed out and sum just stays
I mean, yes.
But like, they have to, without the filter.
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!!!
I think the science comes in showing that it does actually work. Like, this is so simple of an idea that I would be skeptical of if it would work if I had had the idea by myself. I’m glad that I live in a world where, if I had thought of this and wondered “is this a good idea, or am I just being dumb for thinking something so simple could work?”, I am able to go online and find information and guides on this and other diy filters
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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.
correct me if I’m wrong but anything higher than MERV 13 has diminishing returns because of increased resistance. instead of going for increased MERV I recommend getting thicker MERV 13 because of their bigger surface area.
CR boxes rely on raw total air volume and increased ACH vs HEPA which relies on filtering as much air as possible on the first pass.
If you go for the 2” thick filters they breathe better and have more surface area.
this is true. I pick up filters from shut down businesses and warehouses sometimes when people dont know what they cost and post them to fbm or craigslist and if they are higher than 13 I also put a filter for the bottom panel since I usually hang them blowing down with cords taped at the corners. even then they start to suck inward.
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?
Link? Used to have one like that but now I can’t find another one
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You’re not a true lemmy unless you own The Rug
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I got it from my parents after they didn’t want it anymore, but I think they got it from IKEA
Those start out white?? I think it’s time to replace mine.
Ya, they were brand new filters from the store. I bought them along with the box fan and duct tape.
This apartment doesnt have a HVAC system (just wall mounted AC unit) so it’s doing all the air filtration.
This is why I buy my HVAC filters in bulk 4 or 8 at a time and replace them every 3-4 months (less if there is smoke). The difference it makes in keeping the house clean is very noticable. I get very little dust accumulation except in my teens rooms because they leave their doors closed.
Christ i wish we could get these filters in au at non-arserapey prices
have you heard of the Ikea Starkvind filters? they’re a bit smaller but you can tape together as many as you want
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You can make them yourself using felt, wire and glue. Might not be exactly as effective but better than nothing.
Can you order from Alibaba?
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.
Ohhhhh that’s a great idea! Thanks for the suggestion!
I really need to make one of these.
Now it matches the rug & walls, though
Funny enough I cleaned that rug after first moving in (apartment was pre-furnished) and it looked clean for a whole day.
I feel ya. My house was miles away from the evacuation zone of the PacNW fires a little ways back, and the filters didn’t last the month. We wore masks with filters rated for smoke whenever we had to go outside, and sealed every external seam, hoping the firefighters could get it under control in time. Thankfully, they’re the public servants that actually know what that phrase means, and to the enth degree. I trust every one of them right alongside our Nat’l Park service members (rangers, et al), sight unseen.
When this nation’s collapse comes to your town, remember this simple rule, fellow US peeps:
Firefighters & National Park Service? Heroes of the people, through & through.
Cops, etc.? Shoot on sight (if that’s your chosen theme for the apoc, ofc.) 😅
Good job, Captain Lovell. That’s some Apollo 13-level engineering right there.
Just doing my part ground control 🫡
Ok. I’ve been looking into this a lil and there are better options than a cr box.
Housefresh has been looking into this and they recommend the nukit tempest or luggable XL or another one - think it was a Canadian brand - as the cheapest total costs over time and lowest sound and most efficient purification. All of those use regular HVAC filters which cuts down on operating cost and are quite big which cuts down electricity and sound.
So recommend getting one of those for long term use, if you have the space for it.
There’s also an open source tempest that you can use a CNC for and customize to your liking with a script. https://github.com/opennukit/Nukit-Open-Air-Purifier/tree/main/Nukit Open Air Purifier-W(all) v1.0
I have an unfinished project to make a nukit with a power knob.
I got a cardboard proof of concept working but need to make my mark 1 out of plywood or something else.
Duct tape an electrical knob device to the front and call it a day?
I’m viewing this post with the Thunder app and I only see one photo: a box with a fan on top. I see no filter. Is there supposed to be a second photo?
The box is the filter
I built one back when I lived in California during fire season, and then again during the pandemic. They do such a nice job making the air less gross.
I think that’s about what mine looked like after 3 or 4 weeks too…