@Blank Name Haven't seen or heard of that happening to any of the ones that have been suspended from ceilings. Have you? The design of the filters is such that they seem to keep their rigidity well in all orientations.

The filter material does sag when it absorbs moisture from the air in a moist environment over time, as in a basement. Easily cured by adding some sort of ridged material (I use expanded metal grate available from the hardware store).

I found the box fans don’t produce enough thrust to push air out, much gets regurgitated. I could t figure it out.

​@Andorian Nationalist you might need more surface area on the filters, perhaps by making it with 8 filters. Box fans dont handle static pressure particularly well because of the gaps between the blades and the gaps from the frame to the blade. So either the box fan needs to be modified/replaced for a blade design and shroud that optimizes for static pressure, the shroud should be inside box fan and in line with the blades. Adding more filters can reduce the overall static pressure requirements so you can get more airflow through the filtration medium.

That 8 year old should be a millionaire. Can't believe anyone would pay to learn this crap

same here lmao

Parallel engineering universe.

He even built his face into the unit. You can hear him struggling from rebreathing his exhalations. Osha has known how horrible this is since the org began.

@@CoincidenceTheorist Bizarre. So you guys really think surgeons, car painters and the entire silicon chip industry are all dying from 'breathing their exhalations'. When did this genius idea first come to you, given that masks have been used since the Civil War to stop the spread of disease?

First to publish gets the credit.

🤣

he’s showing you a simple at home DIY project and you feel the need to insult him out of pocket? 🤔😵‍💫

He realizes that the mental preparation of young students produced by the department of education these days means this is about all most can understand.

🤣working alone while wearing a dust mask in what appears to be a dust-free environment 😂 cant make this stuff up 🤣

​@@justindy333you can see the second camera moving

Woodworkers have been making these for decades. Not sure we should be calling these Corsi Rosenthal.

Because they made a video. Lol

Guy standing by himself wearing a mask has no credibility.

​@@skeptigal4626 More than you

@@skeptigal4626 it's probably in California. You gotta wear a mask while you sleep

This is the “it took a 1/2 million dollar education and pHD version. Btw: phd stands for post hole digger wannabe

The two nutty-professors.

Nah he clearly invented it.

@@iloveit9468 ok ill tell my robotics engineer friend he wasted his time and that his 300k job is for losers. I'm sure he will be happy digging holes, competing with illegal immigrants for jobs.

@@JimmyRussle exactly you tell em!

My furnace has a 4-inch filter box and they are quite a bit more expensive. I get a 2 pack at Home Depot for about $40. They do last a lot longer though.

I have been taping two 1" filters directly to the box fans for years. Not the cheap ones either; I find that a Merv 14 primary and a Merv8 pre-filter works really well to keep allergens down. Same fans, very little stress on the motor.

Stress on the motor? Ridiculous.

@@NukeChiefMech it is... If they would know a little bit about fluid dynamics they would know that the air resistance for the fan actually decreases with less airflow (i.e clogged filters), because it produces a lower pressure zone, which reduces drag. But hey. I'm just a guy on the internet.

Eight months after your comment, sorry for the necro! I learned recently about fans and "static pressure". Anything that changes the intake vortex drastically reduces the efficiency. By putting the filter on the intake side, it should still work, but not well. That's why the box shape. Allow some space in the intake side to get more pressure.

prob in a room all by himself too, looking like a platypus or something.

Marketing. It's not who had the idea, it's who sells the idea.

that's how probably half of all "discoveries" and "inventions" are made... someone with an education sees something made by someone who is a real world pragmatic problem solver, steal their idea, maybe improve upon it, maybe not, then name it and patent it...

@@Spiritof_76 Edison....

@@nomchompsky2883 Got any statistics?

Don't you love how this guy just loves saying his own name? And his build skills are up there with my son's - when he was 6.

We had these in middle school in wood shop in the 1990’s. This is not new.

yeah...this is not new. Also, duct tape is not actually the best way to do this, you really need the aluminum tapes HVAC actually uses to seal ductwork. Duct tape dries out. Frankly, a better design is with two filters forming a triangle with the fan.

@@truantray Why would you think the triangle one is better? Curious cause I built a triangle one with aluminum HVAC tape and planning on upgrading to a square one like what is shown

I was wondering the same thing, this is nothing new but they just put their names on it and act like they are the first ones to put furnace filter on a fan.

Most home workshops used this for decades. Sad they felt the need to take credit for this.

@@truantray Making an instructional video to help people isn't "taking credit" for it.

would love to see an instructional video of this one that you make..

@@jhwatchlist6927 Naming it after yourself pretty much is….

@@jhwatchlist6927Slapping your names on it and repeating them over, and over, and over again is though, so there’s that.

He jumped on the Covid Cult train in a sad attempt to make a name for himself. Sad.

@@tombiggs4687 At least he's trying to do something and not whining about having to where a mask or pretending that pharmaceutical companies making huge profits means that a vaccine is "bad".

@WeavingBird if I had tried to apply my name to a concept as trivial as this much less one that I didn't come up with myself I would have been expelled for violating the honor code. You're not talking about the discovery of some novel method for extracting DNA from a cell you're talking about pulling air through a filtration medium with a fan... something that was first done over 150 years ago. I can't imagine any scenario where I'd want to look at research into something generic like this from a specific person where I wouldn't just search for research done by the person's name. It's the exact same outcome - people find the research searching for your name with the difference being you don't have to name something after yourself which you didn't create. The culture in academia is bonkers, in my experience outside of government politics I'm not sure I've seen bigger egos present anywhere. I'd say the number of times the guy mentions it - even to the point of it being awkward - makes his intentions clear.

I love how he is celebrated like this expert, but he has no idea what he’s doing. MERV 13 filters do not filter the “cold”. He’s using toxic duct tape to seal it, and no pre filter no carbon filter. It’s amazing! I’m not an engineer, just a nobody, and I know 10x more than he does about his own job! Amazing!

⁠​⁠​⁠@@ZxAMobile pre filters are not needed for merv 13 filters. Pre filters are only used to extend the life of HEPA filters. Almost all cold virus travel in aerosolized particles which just about any air filter will trap (they are relatively huge). HEPA filters also outgas, so that’s not much different. Carbon filters don’t actually filter particulates. It just reduces VOC / odor until it is saturated. Most air filters don’t have the carbon filters sized correctly for the CFM. So they don’t do anything after a while. Dunning-Kruger.

And we get the smoke from your forest fires in Idaho 😂😭

@@SalivaKZfaq They're not my fires. Blame the weirdos who go out into the woods.

​@@SalivaKZfaq and in Utah, too.

@@BigFrankieC I blame the weirdos who delay until the blaze is big enough to get federal money.

@@DistracticusPrime I blame fire. I think that in this situation, fire's the real jerk. Stupid fire.

This one uses MERV-13 filters and is intended to filter virus out of the air, so its purpose is a bit different even if similar in implementation.

@@johnklein338 I built mine years ago and used MERV-13 filters. Woodworkers have built these for like decades. There's absolutely nothing nothing new that these self-important professors have built here.

@@linsen8890 actually important profs have saved countless lives. Sorry you're sore about it. Not sorry.

@@johnklein338 😂🤣😂🤣 I'm sorry that your reading comprehension is so poor. Not sorry.

It's a great thought, but it is extremely dependent on how powerful your fan is. You need a certain amount of static pressure to pull air in, too much and your fan will actually pull in surrounding air around it without actually pullling all of the air through the filters and push it back out too easilyy, something people forget to mention. Imagine placing a plastic straw into a bag and you start sucking on it. Well, you mouth creates perfect suction, but fan blades attempting to pull air out don't. errors in curvature of the blades, etc, will not pull 100% of air through the filters. This is an easily provable experiment. Take a filter and place it in front of your fan where your fan has to push air through the filter. seal all air gaps off. If you hover your hand over the back of the fan, though it only pulls air in, opposite of the filter, you will feel air blowing backwards back towards your hand. Perplexing right? Your fan can only pull air once way, so how can it come back at you? That is all of the immense amount of air not being filtered and being backflowed.

@@Phalenx15 'It's a great thought, but it is extremely dependent on how powerful your fan is.' Exactly, but you have it reversed. More filter surface area means more area for the air to be drawn through. That makes it easier on the fan with 5 filters, not harder. Restrictions reduce as you add more pathways.

LMAO 🤣👍

What's up with the industrial mask? OH yeah it's California. Idiot capital of the world.

It’s a novel method to reduce viral loads in the environment, not sawdust.

He didn't name it after himself. The fact that you assume you know things that you never bothered to research is pathetic. Stop making-up stories so you can pretend that you know what you're talking about. Here are the facts you couldn't be bothered to discover on your own. I share them here for the benefit of others: In August 2020, Richard Corsi, an environmental engineer and the incoming Dean of Engineering at the University of California, Davis, spoke with Wired reporter Adam Rogers about an idea he had for combining multiple store-bought filters with a box fan to improve the efficiency of home-made air filter designs. Rogers contacted Jim Rosenthal, the CEO of filter manufacturer Tex-Air Filters, who had collaborated with Corsi at the University of Texas and in the Texas chapter of the Asthma and Allergy Foundation of America, to run some tests on a single air filter attached to a box fan. Inspired by Corsi's idea to use multiple filters, Rosenthal later came up with a five-filter design. **Rosenthal named it after Corsi,** although after a New York Times article mentioned the boxes by that name, **Corsi tweeted that Rosenthal really deserved the credit,** and that he preferred the name Corsi-Rosenthal Box.

You don’t call a PhD "Piled high and Deep" for nothing.

Yup

@@blipco5 How embarrassed are you to realize that the guy in the video didn't name the box after himself? How embarrassed are you that you believed the commenter, whose ignorance led you down that path, and you weren't smart enough to avoid the trap? Probably not at all, because you likely share that ignorance. A smart person would realize their mistake and correct it. Will you? Probably not. So, maybe it's only the stupid people who refer to "PhD" as you do.

It’s for viruses, not sawdust! No woodworker thought this was reducing viral particles in the air. Source: I’m a woodworker.

Until the fan motor burns up. Yes, that is a great idea. Stand by with the fire extinguisher.

I was going to say, this was really common when I grew up as a cheap way to filter paint booths... and you can probably find many KZfaqrs using similar solutions for makeshit paint booths as well. It's also really common to filter wood shops on the cheap...

​@@looncrazfun fact, they also invented the Corsi-Rosenthal mouth and nose muzzling device

yes, the "pandemic" significantly accelerated the transfer of power in our society to the useful idiots and communist busybodies who are now all stunning and brave geniuses, and in fact are themselves in all their sanctified glory, The Science.

That's exactly what I was thinking... and this is the dean of engineering that names a simple box filter after himself that thousands and thousands of people have already "invented" and built themselves to try to keep sawdust down in their hobby shops.

Well, woodworkers have been building and using them for years. I have a similar dust filter in my shop, built using two filters stacked, and I've been using it for years without any problems with the fan. They create plenty of pressure for this kind ot application.

excellent comment. Can a basic test of static load on a fan be done with a sealed box (or metered output), a manometer, and a fan? Trying to understand the concepts at play here

Good comment, thanks. I've done the two windows one box fan trick for years, though, and I can feel the air being pulled through the house. I'm sure a drum fan would be more effective but, as far as I can tell, a box fan works too.

Thank frick someone finally said it. And like wph above said, that THIS guy tries to put his name on such an old DIY thing is something else. Incredibly distasteful if you ask me.

You can now buy air filters with an activated charcoal layer.

I just searched a bit, and three sources said the filters should last 6 MONTHS, but if they look dirty, change them sooner. I also read that because of the noise, LOW or MEDIUM is good for occupied rooms, but running it on HIGH will "move more air" so maybe more effective on high?

@@GeeAre is correct, it is a trade-off between noise and the Clean Air Delivery Rate [CADR]. Most fans will list dB for each fan speed and it may be worthwhile to include that in consideration when selecting a fan.

Medium is usually the happy medium. You can find a number of CADR estimate papers online and there's a reasonable jump between 1 to 2 but less between 2 to 3 for most fans/designs. But if the room is unoccupied and if you want max cleaning for a shorter period of time (say a teacher who wants to eat in their room after students leave), definitely run it on max. Electrostatic filters are good for 90 days only, unfortunately. And you really need the electrostatic properties to catch virus-containing particle sizes of things.

​@@emma70707Do you mean they last 90 days if they're running 24/7, or they last 90 days regardless of how long the fan runs?

Removing the finger guard would not help, except by giving you access to improve the fan. If you can add a duct just larger diameter than the fan blade tips, that improves static pressure. This way, a smaller device can clean more air.

I’m pretty sure it will be just as efficient horizontally. He suggested the vertical alignment so that the filter material wouldn’t sag over time. I guess it will last longest aligned vertically. I can see how they would sag more in a more humid environment.

Shouldn't an engineer know that? Especially the dean of the engineering school!

_"eject all that clean, filtered air outside at once!"_

That makes no sense.

Boy you are gonna be really upset when you learn what they are calling "tool with stone head". The youngsters are out of control.

leave it to academics to jack themselves off about slapping some filters on a fan. these people are beyond useless.

More is more

you have to test. it could make vortexes that push back air . make a video!

Fans in series sum static pressure. Fans in parallel sum flow rate. Look up pump curves for parallel and series. So two fans in series would result in slightly more flow due to shifting right on the curves due to the increased static pressure.

@@Ryan-dj5ku but air and water behave differently as does a fan shape versus a volute body like a water pump. And you don't have a sealed system that doesn't have any losses

He's a clueless academic who thinks he invented this and then has university PR promoting it to exploit the pandemic.

Guess your dad should have put his name on it and then repeated it over and over again.

The opposite is true. This design in the video makes sure the air coming through the fan after passing through the filters is clean air. If you do it with the fan and filters pointing in the other direction, dusty air would be pulled directly into and through the fan which would quickly make your fan really dirty….same reason why in HVAC and floor air scrubbers always have the filters before the fan when you look at how the air flows.

Personally, I would prefer to have a dirty fan than dirty lungs. But that's just me. This design looks good on the professor's papers, but would perform poorly in the real world if you are using it for sawdust in your wood shop, especially if you utilized a drum type fan or one with with higher cfm. Blowing a high volume of air out from the top, the sawdust would be sucked inwards, lodging on the room exposed outside of the filters. Every time you moved or bumped the unit some of that dust would again become airborne. To make matters worse, the large amount of air blowing out the top would ensure that the sawdust already in the air would continue to be churned up and recirculated throughout the shop, and at a level where you more readily inhale it. While it will take some of the sawdust out of the air, you have effectively created a dust pump, but at least your motor would be clean. Simple solution: Use a TEFC motor fan/blower blowing into the enclosure. The dirty air will not affect the enclosed motor and much of the dust laden air will essentially be pulled from the level that you are most likely taking your respirations from. The force/turbulence of the output air will be greatly reduced when it passes through the filters, and it will exit below your nose/mouth if it is placed near the floor. More surface area for filtration would be best, decreasing the back pressure. This would be a good opportunity to place that 5th filter on the bottom, or even go to 8. This guy has done some research on similar home remedies and has several good videos on building different levels of this basic "Corsi" filter: www.youtube.com/@The3DHandyman Here's another home built dust cleaner idea. Check out the rest of his site for an exceptional understanding about the hazards of saw dust and how to deal with it: billpentz.com/woodworking/cyclone/air_cleaner.php

You might care when the fan motor ignites.

The exhaust already won't have any dust, it's all running through the 4 sides of the filters.

about as often as he changes his ineffective n 95, lol

Wow, that's a great idea! Also, large fan will ensure good air flow for cooling your computer. Love the idea!

@@sander_bouwhuis Actually.... it probably will NOT ensure good airflow. You would need to narrow the opening (Bernoulli effect) to get enough flow.

That is a truly bad idea.

Yes. It likely won't clean the air as quickly but the core principle remains the same.

That's what I have, it's all just horizontal.

One reason is that when the fan is blowing out, the air stream encounters no resistance blowing into a large volume, and pulls air evenly across the filters. When blowing in, the air flow will be turbulent and impact some areas of filter more than others. Aside from that and keeping your fan clean, no huge reason. Some people build them with the blower pushing in, I think more common with people filtering shop dust near a power tool or work surface.

No. The fan needs to pull air through the filters.

most woodshop fans i see are reverse , rember to flip teh filters not just fan if your filters are directional. some have reinforcements so backwards air flow they buckle The 3D Handyman has a good demonstration

Pushing air into the filters reduces the airflow.

"While mold, dander and pollen can be captured with filters rated MERV 8, it takes a MERV 13, MPR 1500 or FR 810 to keep smoke and tobacco smoke out of your indoor air." I'm not sure if the odour will disappear, however. VOCs aren't removed by a MERV13 filter for example.

1. With 5 sides unblocked will get you 25% more air flow 2. IMHO, you want it placed where people gather / next to people to be more effective

I noticed the prof was careful to always specify "aerosol particles". Those are big enough to get stuck in some filters.

i knew he didnt invent anything except another way to take credit for somone elses work I did not know it was commericaly available thanks

🤣🤣🤣🤣🤣🤣🤣

Posted 'Apr 15, 2022'. But pretty sure it was actually invented on April 1st.

Typical filter life is 3 months for 1" thick, 6 months for 2" thick, and 12 months for 4"

MERV 13 would clog up very quickly in a shop environment. For those situations a vacuum at the point of material removal is best. If you do build something like this a much lower MERV rating would be better.

Not even close.

Does anyone have this information?

From other videos, they said 900 sq. ft. giving 3 complete air exchanges per hour. They suggested one move the box in proximity to where you are. This was from the "This Old House" guys on KZfaq.

The ballpark rule of thumb is 1 CR Box for every 500 ft² of floor space if you want 6 ACH (Air Changes per Hour.)

Pretty big. I put one in the barn. My sheep love it.

Fight the flu? Notice how influenza a and b disappeared?

@@US2A No cuz I had Flu A couple months ago

@@gethype5064 it literally doesn't pop up on deaths anymore, hundreds of thousands died from the flu each year before covid, now it's only covid deaths.

School colors were great.... Dollar Tree sells fun duct tape as well as Michael's craft store if you're looking for local vs ordering online. I'm not a huge online shopper. You can also use any duct tape and buy craft vinyl from Dollar Tree and cover the duct tape to really make it uniquely yours.

This isn't going to help with any airborne disease.

I wonder if anyone else has named something that has existed before? Something for me to think about at my next soccer game.

@@montee827 You should ask the British, who gave Association Football the nickname Soccer.

@Blank Name If the goal is filtered air for less money than no, it's more efficient. If the goal is just to move air, than yes any filter lowers efficiency.

@Blank Name Why not just remove the one filter? You'll move much more air.

@Blank Name What is the point of the air filter you built? How would I know that?

i do that to my aic because of the dods, the single pleat green ones fit over the good filters and save a forrtune

With the fan blowing out it sucks the air in through the filter media, which is what traps the contaminants (regardless of fan direction). Blowing out helps keep the fan clean. I believe it also provides more air flow, but don't quote me on that bit :P

Thicker filter means larger/ more pleats. More pleats means more surface area for the air to pass through and better filtration. I've never heard of a CR box collapsing.

@@DonnaAndCats with 1 inch thick filters, they become very flimsy. As well as a more humid environments. I've done it now with just 2 filters in a "V" formation, and I've noticed it still has the same cfm as it did with the 4 boxed frame style. (But I also have the slightly more powerful box fan lasko makes). All in all the only difference I can determine would be the need to replace filters sooner. But I'm looking into reusable hepa/ionic filters, they're just darn near impossible to get in a 20x20 design. But they would be an excellent, long term solution. And perhaps allow 2 fans opposite each other with a 3 filter system between them.

@@carterscustomrods Nonsense. It cannot have the "same CFM" - since the surface area is doubled. More surface area, more restrictive to airflow, less CFM. Right? Right.

@foobarmaximus3506 it had the same airflow that it did with 4 filters. But, the cfm dropped a lot quicker as the filters started to accumulate particulate. After about 5 weeks, the airflow was noticeably lower, and the filters were darker (as one would assume in a 2 vs 4 filter setup). So I ended up taking my 2 filter V system and dropping it down from an M13 to an M8. But I'm using mine in a woodshop and I don't need to trap virion, or anything like that. But when filters are new, and fan is on high, the filters didn't change airflow in any noticeable way. But having the stronger Lasko box fan mightve made a difference. The only changes in airflow I was getting was if I didn't have the corners of the fans face covered. That actually slowed down airflow when I assumed it would increase it. Do you definitely want to have the face of the fan setup with the rounded corners on the finger guard.