Build a Do-It-Yourself Air Purifier for About $40

[@km3247]

This guy's wearing a doctor coat and has lots of books on the shelf so he is legit for sure.

[@mikel4510]

It it's on the internet, right? LOL!

[@epigeneticnerd4244]

It has his name and that he's an MD. What more do you want? They just chose a random room to do this in.

[@FlyBoyKhi]

a doctor coat lol

[@phayzyre1052]

Kris, he seems legit to me! www.uofmhealth.org/profile/280/jeffrey-evans-terrell-md

[@corcon6976]

Pete Miller, Those are mostly internal medicine books. They're real.

[@SaraA-ul2iy]

I’ve been using these for years due to wild fires and seasonal issues. It has made my family’s life much better. I know this video has been out for 10 years but I wanted to let you know I appreciate the work you put into it and it is still making a difference. I just shared it with a bunch of friends due to wildfires.

[@davidanthony2917]

Two years ago, my step-mother, who was an Obsessive-Compulsive Hoarder died face-down on the living room rug from an asthma attack partially caused by the dust in the room. After her death, I cleaned out the floor of the house. Despite wearing a surgical mask, my lungs became sensitive to irritants and I've been coughing for months. My apartment was just too dusty and I wasn't keeping up with cleaning it enough. A few weeks after following the instructions on this video, my coughing has completely gone away. This idea may have saved my life. Thank you.

[@M855A1]

thats fucked up if that is true

[@DavidAWA]

Downtime It was fucked up and it is true. I'm heading home for Thanksgiving and I'm making two of these for my Dad because the house is still not safe.

[@epicdeuce]

I'd recommend a Roomba

[@hectormayoral443]

Did you place the filter on the front or on the back? And if on the front, how do you deal with the fans getting dirt? You just clean 'em? How often? Thanks. I've been coughing and hacking for the past month. Allergies me thinks

[@druidboy76]

David Anthony sorry to hear about your mom dude.

[@morbo3000]

No! The filter needs to go on the *intake* side of the fan, not the exhaust side. Otherwise the fan itself will become clogged with dust and dirt. This is why HVAC systems filter air on the intake side, not at the vents.

[@DicerX]

I would suggest placing the HPA filter on both sides of the fan.

[@morbo3000]

Demi God I suppose if you care about the tiny leakage, putting it on both sides can't hurt.

[@DicerX]

+dllexport- well I am planning to replicate this with filters on both sides once I find a cheap squirrel fan. I am growing some button mushrooms or Shiitake mushrooms cultures. Need this to be as sterile as possible.

[@SusanStoneSalas]

I was wondering the same thing, maybe he did this as a demonstration example as his measurement tool might not be as effective with the filter on the back side with air leaks.

[@DicerX]

+Susan Stone Salas yes most likely.

[@AnabaptistMom]

Ignore the rude unkind and sarcastic comments of incredibly insecure people. So.... I woke up this morning and..... IT WORKS! No stuffy nose, soar throat or headache. It really honestly made a huge difference! I am so excited I am going to make 5 more for my home. I made mine just like the video instructed. It costed me $37 ($17 for the fan & $20 for the filter) to make buying everything new at home depot. Thank you so much for posting this video. It has been a real help to my family, especially because me and my son suffer from asthma and a sever allergy to dust mites. We have removed all carpeting, switched to wood blinds and keep very little cloth covered furniture... after all this... this little idea has also made a huge difference.

[@kirkwatstien6979]

It COST YOU NOT COSTED YOU get a 2nd grade education before you post

[@millenial90]

@@kirkwatstien6979 So following your logic, how much education does it take to see that the comment you replied to is 5 years old? But honestly, it's okay to correct people, but you can do it without being a jerk.

[@charlottegouriou8613]

@@kirkwatstien6979 you should get a heart sometimes, something a lot of people are missing these days

[@billa5482]

@@millenial90 lol underrated reply here. this dude is a true idiot commenting on 5 year old posts

[@rfink222]

@@millenial90 You can correct someone who says "costed" over and over but they will keep saying "costed". I know from experience.

[@ceofounder]

Thank you so much for this excellent, informative and educational video. I actually went to home depot, and went online for the hepa filter and a fan. This method works 100%! As a asthma sufferer for over 20 years; always wheezing on & off due to allergens. The fan and filter came up to $37. No more wheezing, nor sneezing in two of my rooms! Whoever uploaded this video; you're the best!

[@johnparis6233]

Did you set it up where the fan was blowing air OUT of the room through the window? Or blowing fresh air (with the filter) into the room?

[@johnossendorf9979]

I work in HVAC and IMO this is a good low cost DIY alternative to expensive air purifiers, HOWEVER, I would put the filter on the return (intake) side not the sapply (exhaust) side.

[@miguellopez3392]

the problem with this might be that the air would then be sucked through the edges of the fan on the outake side since it wold produce significant resistance to airflow on the intake. so it is just better to form positive pressure on one side instead of instantly retaking the air it just blew out.

[@BrettonFerguson]

Do the math. Buy a 24" fan, a roll of tape, and a 24" x 24" hepa filter all for $25 where? You can buy decent air purifiers for $50. If you buy a $3 filter it isn't going to filter out anything much you are in danger of breathing in. The doctor know this doesn't cost $25, that is why he said "about" $25. Like he had to guess because he lost his receipt.

[@lfrankow]

The fan motor needs airflow to keep it cool. Thus the filter on the exhaust side.

[@jasexavier]

@@lfrankow Most fans that plug into the wall use induction motors, which are (more or less) constant speed devices. So, if you reduce the load on the fan by decreasing the intake pressure, the motor will not spin faster like a brushed motor (e.g. the one in a vacuum cleaner), but rather will consume less power, and generate less heat. Placing the filter on the intake side does this. There will still be sufficient airflow to cool the motor, especially with the reduced power consumption. Placing it on the exhaust side increases the load on the fan, increasing power consumption and heat. This setup will move more air, but still significantly less than without the filter. The motor will run hotter and have a shorter life. It's a bit counter intuitive, and it's a trade-off. More flow for a shorter fan life, or less flow with the bonus of never needing to clean the fan itself. I've always preferred the intake side, but either will work.

[@jasexavier]

@@BrettonFerguson When this video was made, home air purifiers were much more expensive, and MERV 13+ furnace filters were cheaper. It probably was about $25 at the time, compared to the $800 IQ air unit. You are correct that today it makes much less sense.

[@maridonis6308]

Dr. Terrell, thanks Is very rare listening to a professional providing information for free.

[@Matt-ou3hp]

This was a great idea. Thank you for taking the time to share your research. Helps out a lot of people that suffer from allergies.

[@pugapino]

Excellent example of a 90/10 rule. 90 percent of the effectiveness for 10 percent of the cost. Very well done 👍.

[@polomare2027]

For years, I've put a cheesecloth soaked in boric acid and table salt on the back of a box fan in my barn to trap mosquitos (it works! I can catch 200 a night) but I never thought to try making an air filter. I am definitely trying this! Thanks, MM!

[@rickrude6301]

Better to pull air thru the filter, if you push air through the filter dust that builds up will get blown off and go back into the room. Also, if the fan is pulling air through, the filter will stick to the fan and won't need as much tape to hold it on. Always handle used filters with care because handling them rough will release concentrated dust back into your air. If possible always take air cleaners or vacuum cleaners outside to change the filters or bags.

[@daveybarra]

Rick, You are so right about the filter placement. The filters should always be the the first elements in the system. Starting with coarsest then finest filtration, if you are using more than one type of filter. Having the filters in front of the fan also means you won't be pulling dirty air across the fan motor and blades. This will result in less, if any, cleaning of the interior of the system. Sealing the filter seat/housing completely is also very important. No leaks that would allow dirty air to sneak by the filter housing. That would defeat the whole purpose. Duck tape it if necessary. In addition I think a box fan is NOT the best choice. I prefer a squirrel cage type fan. Even if you have to build a box around it to seat the filter. Squirrel cage type fans have a much higher flow rate. The more air you move the fast it gets clean or the more air you can clean.

[@cheapmovies25]

thats how the store kind work, the filter goes on the back, with a pre filter behind the hepa. i get the pre filters at home depot, and just cut them to fit and use a little piece of tape to hold it on the back of the machine. the other filter snaps in place, they can be expensive - but i found that if you clean it every 3 months you can get it to last a year. i use bleach and dish soap water with baking soada, and then rinse in clean water with a little more baking soda - so the bleach kills all the germs and the dish soap gets rid of all the dirt and grease, it comes out nice and white, with a little tint. the soda just dissolves in the water, and stays in the filter, which is good as it absorbs odor. i use the smoke filters, as in the winter, its too cold to go outside, lol.

[@kathryngoodman2124]

David Ybarra

[@harryblowfish3268]

David Ybarra Hmm, a "squirrel cage" type fan... I wonder what that is? Excuse me while I go ask a squirrel. Oh, and before I go, I'd just like to thank Dr. Terrell for his very clever idea - - I've always thought "air purifiers" were far too expensive, and the filters as well.

[@Christynmaine]

Harry Blowfish A squirrel cage fan is the kind of fan that looks like a snail.

[@maxcohen13]

Thank you, sir, for traveling from 1982 to tell us about this great idea.

[@funnyguylol69]

My right ear enjoyed this video very much.

[@nope4018]

Good thing the music at the end is both channels...

[@RumzDizzle]

I spent half the video trying to fix my headphones until the end. Get a stereo recording set up UMICH and quit paying J. Harbaugh so much for mediocrity.

[@Quizmaster999]

LUL

[@monicamedina4467]

Same here

[@rickemmons8023]

I had it on left

[@olehelgerson7996]

Agree on placing the filter on the fan's intake side. Also, low speed setting. No tape needed. A little bypass is likely ok. Been using that system for years. It works. Monitor motor temp. Some fan motors reportedly may overheat from the extra load. Never had a problem on low speed setting. Just takes a while longer to clear the air.

[@Groovyman-je6yb]

I just made one of these today and I put the filter on the back with long zip ties. These move ALOT more air than the much more expensive air purifiers, that cost so much more yet purify less air. Great idea, thanks!

[@dmanc53]

thanks for the zip tie tip

[@RadiationNetwork]

Congratulations on your new home fire starter kit. The motor does work harder on those Lasko bladed 20" fans when restricted and the amperage climb some. They are not squirrel cage blowers. Massively restricting 20" bladed fans like those Lasko's is a MAJOR fire hazard. That model Lasko is closer to 2,000 CFM and will drop to 50-150 CFM. The guy that posted this video is an idiot. Those motors are AIR cooled and taking away >90% of cooling is a fire ready to happen. Massively reducing the air cooling by dropping air flow 10-20 fold causes the windings to overheat. There were 20,000 House fires from 1990-1998 alone caused by portable fans. @t You need to use a properly designed squirrel cage blower made to handle the static pressure drop. When clogged the amps drop not rise like in bladed fans. I'm an ex Red Badge Nuclear Fire Safety Inspector at San Onofre.

[@productrecalls3389]

@Manny LOL Radiation is spot on. You posted the dumbest post ever on KZbin.. He pointed out a potential Fire hazard and referenced 20,000 fires and you say fire hazards are OK if you have many of them. ROTLF. You’re not the sharpest tool in the shed but you are a tool.

[@russphilly]

@Manny ImBeCiLe ...

[@-kepha8828]

@Ilir Cami you do realize that people are trying to create a box fan hepa filter because they dont have $100 spare to spend, dont you? Most people already own a box fan and are hoping to attach a filter to save $90. If you have $100 dollars to spend, then this video isnt for you obviously.

[@bloqk16]

A variation you may want to consider with this, that is, if the operating controls are at the top of the fan, and not in the back of the fan: Mount the filter on the back of the breeze-box fan so that the air is drawn through the filter . . . as it seems to vastly improve the air filtering capabilities. But, in doing so, run the breeze-box fan at a speed no faster than medium. I ran this setup in past years, and ended up wearing out the fan's motor when running on "high" when I kept the fan running for several hours.

[@FT__Cool_Stuff______-of5pi]

having the filter on the front will likely make the fan motor last longer, because it will have more air moving over it and won't get hot.

[@robertbee9776]

I hot glued four filters in a square with a two inch wide strip of cardboard hot glued to top edges, then a 1/2 in wide foam casket attached to the top edges between the cardboard and the box fan. This way you can use as many as four different types or grades of filters if you like and can cover or uncover with a piece of paper the ones you want to use to do the filtering during high or low pollen or dust periods. Filters are not cheap, so you choose to cover all but the ones needed. Best of all, only filters and a fan are needed as well as glue or tape. Any paper can cover the ones not in use and the fan stays clean with the air flow vacuum for the filter intake. The bottom does not need a filter as it sits on the floor. Check that your filters are made well as some need to be hot glued where they may have loose filter material on their sides that may let unfiltered air pass. Inspect your filters before you build. It work very well.

[@jamesdorsey7145]

Thank you so much for this solution. I live California with so much smoke and debris in the air for weeks due to the raging fires. This has saved my family from having to travel across state lines during a pandemic. You're awesome!

[@MichiganMedicine]

You're welcome! Glad it helped.

[@1curt12]

Been doing this for years. I love it. Less dusting is a plus too. Usually have 2 of them going all day every day

[@abadabababadaba4774]

No problem with the box fans dieing? Just wondering how much stress this would put on the fan? Also how much extra in electricity costs do you pay per month for the two approximately? I am try to figure out if I should do this or buy Honeywell air purifiers. Thanks for any help.🙂

[@johnparis6233]

Do you set it up where the fan was blowing air OUT of the room through the window? Or blowing fresh air (with the filter) into the room?

[@lisamackay4532]

Thank you! Just watched this with one of my employees whose doctor recommended an air filter for her daughter. She's so relieved to find an affordable option to try.

[@fhussain44]

I found bungee cords work the best to secure the filter to the fan.

[@Nya48506]

That is what I did. You must be an engineer. Where did you put the filter - intake or exhaust?

[@cIeetz]

Home Depot just restocked the 20" x 20" filters for around $20 and my uncle dropped one of these square fans in our garage (among tons of other things, he liked to collect) . Im so thankful, thanks Frank! It has exactly a 20" x 20" surface and 4 speed settings. Its going down today :D

[@buddyroach]

would it be more efficient to put the filter on the back of the fan to keep dust from getting on the fan? But what do I know? I dont have a bookshelf full of encyclopedias.

[@silverfoxstudios9351]

+buddyroach Damn that is one ugly ass profile pic you have there!

[@ericbradley7597]

+buddyroach bahahahahahahaha I'm (o-fish-ali) DED!!!!! bwahahaha

[@anterpants]

+buddyroach Yes, but do you own a lab coat?

[@ericbradley7597]

lmao I do for gay sex foreplay reasons lol

[@anterpants]

At least I'm not the only one...

[@rclewis01]

Some people think that the fan has to work harder. But this is not true. Centrifugal fans or water pumps work less when throttled. I've taken a watt meter and measured the difference with a filter and without. Power always goes down when you have an obstruction. Also, the furnace filters have a MERV rating based on furnace air flow, typically 2000 CFM or more. If you take a MERV 12 and put it in a system that has half the air flow, the effective MERV rating goes up to 14. This is because tiny particles are captured through diffusion and the slower the better. A cheap 20 inch box fan is typically about 700 to 1000 CFM on low. If you put a MERV 11 filter on the back side, it drops to about 150 CFM. That means the MERV 11 turns into a MERV 15 or so. Also, a big fan will move more air than a little air purifier. And each time the air passes through the filter, about 75% or more is removed. So a small HEPA purifier in a typical room may never clean all the air, while a big fan with a MERV 11 or better filter can do the whole room in 3 hours or so. It is also cheaper and filters are a lot less and easier to find.

[@aeden77]

Very informative response. It's much appreciated!!!

[@rclewis01]

***** There isn't a big difference in principle, both are centrifugal and work on fluid dynamic properties. If you throttle your water pump too much, there won't be enough cooling for the pump itself, EVEN THOUGH IT IS USING LESS POWER. In other words, a pump at 1000 watts could be throttled down to 100 watts, but you still have to get rid of 100 watts of heat in the coils of the motor. A box fan is so leaky around the edges, you could completely seal off the back side with plastic and it would use less power but still wouldn't overheat because air leaking in around the front edges. Just say that it is like the cheapest pump ever made. Just look in the HVAC industry, a simple blower (not a ECM blower that compensates for pressure drop!!!!) a SIMPLE blower will draw less amps when the filter becomes clogged. It will have to run longer to get the same heating/cooling effect, but it does so at a lower amperage. For a box fan, it is a simple motor and throttling it will make it draw less amps and it is running 24/7 anyway. Each filter drops about 90% of the dust from the air. If you stack two filters, air flow goes down, power goes down slightly, and you filter at 90% twice, therefore it becomes a 99% filter at about 100-125 cfm on low. And slower air means smaller particles are filtered better through "diffusion" filtering. This means you would filter at over 99%. The little Honeywell is only 95% and about 55 cfm. I have one and it doesn't really do much unless you have a small room...less than 10x10. You said ".do an experiment for me....i want the ppm from a box fan air system....do an air quality test before and after..get back to me and lets open the floor for debate." Isn't that what this video just did? Did you actually watch the video?

[@squirrelattackspidy]

Richard Lewis Hi Richard. I'd appreciate it if you could answer a question for me. I got the same fan (Lasko) but it's an older model. I taped the filter to front of the fan and with correct orientation (air flow going same direction as fan). When I do this my fan motor smells like it's burning. I was thinking that maybe there is too much resistance with the filter attached like that. Could that be possible. Does it make more sense to move the filter away about six inches so that the fan blows into it but it's not obstructing it as much? I also think you'd get less blow back and more clean air going into the room.

[@Matt_McFaul]

The Lasko fan is driven by magnetic coil, as far as I can tell. It has 3 settings which alternate between 3 separate resistor circuits to produce 3 separate speeds. When the switch is in one position then the fan will be allowed to draw X amount of current. Since it is the resistance to the voltage and not the air resistance to the fan which controls current, then I don't see how it could possibly be true that adding resistance to one could possibly reduce another. The coil is the motor which exists around the magnets surrounding the axle which holds and spins the fan blades. The coil will use the same amount of power regardless of how fast the fan is spinning simply because the coil is the end of the electrical (or electronic) circuit. Even if you remove the fan land magnets then the coil will still draw all the energy the circuit allows it to draw. Therefor, I don't see how it could consume any more or any less under any circumstances. I am open to explanation. I do have a watt meter somewhere, though it's unlikely that I'll find it anytime soon :-)

[@Matt_McFaul]

***** moving the fan further from the filter, without building a tunnel to contain the air intake, will simply result in the airflow bypassing the fan. Airflow is similar to electricity in that it will always seek out the path of least resistance. A fan filter is big resistor basically. Your fan shouldn't heat up from the any sized filter unless you have fabricated a shroud to prevent in flow from the front corners. You can place your fan flat on the ground and it will simply go from taking the air from the rear to taking the air from around the edges of the face. Which is why someone here mentioned noticing cat hair sticking to those areas on the front. The filter is creating enough resistance to make taking the air from the front and easier option for the fan. Just like a vehicle's radiator fan...you need a shroud to block off those areas around the blade path.

[@turtlemouth]

I kept waiting for him to whip his glasses off when making a point. That's how I know someone really knows what they're talking about.

[@stephanieluigon5192]

Additionally, he really needs a clipboard.

[@parteibonza]

@@stephanieluigon5192 and a pocket protector. But seriously, I have been using this system for years and it really works in my tiny apartment. I leave the fan on all day on low and you can really tell how fresh the air is when I come home.

[@Aquariance01]

💀💀💀💀💀

[@pettypatty329]

OMG! lmmfaoooo!!

[@ElkeNikol]

In my experience with it, if it's on the front and taped very tightly, there is so much backpressure created the airflow comes out of the back of the fan (intake side)!! I removed the tape seal around the 4 corners and now it is "leaking" but flowing much better, and the air quality has increased noticeably. It is not reducing smell quickly though, very very, slowly, unlike a true HEPA filter, which does it very quickly in my experience.

[@jay-d8g3v]

yup, had that problem. took another filter on the back to equalize it

[@cherylciecko7110]

I use this for myself and my family and can attest that the filters become dirty and need to be replaced... What a great value! Without it I wouldn't be taking that dust out of the air. As an architect, I specialize in mold avoidance and moisture management in buildings. Mold lives on dirt and dust, including what is found in the air that we can't even see. We can't see mold spores either. Reduced dust is a major step towards better air quality. Other airborne particles will also be collected which is better than breathing them. This is a very affordable way to achieve it! Thank you for sharing Dr. Terrell!

[@Marcuswelby-nx2te]

We don't care miss stuck up you and doc are a quink

[@WalterKnox]

that is a great idea. never thought of it, i have a bunch of box fans I do not like and this will help to get rid of them by blocking the air flow to the motor and overheating the windings, then i can simply throw them out without feeling bad about throwing out a good fan!

[@Matt_McFaul]

One problem that I noticed, while the filter is mounted at the rear (sucking through), is that there is still a path of least resistance around the front edge of the fan which allows air to be suck into the front and then pushed back out bypassing the filter. I discovered this when using HVAC tape to mount the filter. After pealing the strips of tape from their paper backing I placed the papers on a table in front of the fan, much to my disappointment the papers were quickly sucked to the grill in front of the fan. The only way to counter this is to seal the front of the fan guard with a shroud that is smaller then, or the exact diameter of the fan blade itself :-/ It still sucks from the rear as well, however I am witnessing much more suction from the front edges then any point on the rear of the filter. I'm on my way to the garage to build a nice oak drop in box with a shroud :-)

[@Matt_McFaul]

also, I haven't felt the motor but it seems to me that any time you add resistance to a motor then it will heat up. Has anyone been running one of this long term and witnessed any burn outs or fire hazards?

[@9001greg]

A fans static pressure is the measurement of pressure it can push against. Box fans have extremely low static pressure and are not good at pushing against any force. Assuming your static pressure is high enough, a filter is always going to collect and *hold* more particles if it is on the blowing side. However box fans have very low static pressure therefore they should have it on the intake side.. I would wrap tape around the whole edges of the fan because as you said path of least resistance. You can cover it so it won't have the air holes. If you're worried about too much resistance you can half the resistance by simply placing two filters in a triangle formation on the back of the box fan. This will be shaped like

[@Marmocet]

Why would the fan work harder? How hard an electric motor works is a function of its design and the current and voltage of the electricity supplied to it. The fan's motor doesn't "care" about how much air the fan blades move.

[@mattross6902]

@@The_Komzik How long have you been using this setup? You tape the filter to the intake side? Thanks!

[@Entropy512]

@@Marmocet Current isn't "applied" - it is drawn, and the current a motor draws is dependent on the torque the motor is generating. More mechanical load = more torque = higher current. Most obvious extreme case - completely stall the motor. A stalled motor without any form of current limiting is likely to burn out quickly.

[@rocketg4360]

I had this idea fifteen years ago whilst on a drug bender. Worked great.

[@pettypatty329]

Rotflol!

[@notreal291]

Same omfg

[@rocketg4360]

@@notreal291 ....Steve?

[@nos4me]

and save the filter to reclaim any drugs that were exhaled

[@Turnah81]

I'm curious if the DIY filter he tested was giving a reading because it was still new. ie the filter would probably shed some particles from packaging and shipping. I wonder how it would go once "run in" nice work though.

[@tag-xr6uk]

The older I get it actually traps finer particles.

[@xex2kok]

You replace the filter as needed. They get dirty just the same as using them the regular way. This works great and is similar to what they have done in Hong Kong for filtering their smog. You need a fan that can produce a lot of pressure to filter a lot of air though. This is totally worth doing if you cannot filter your air any other way.

[@xex2kok]

​@Nipha Ahtlantashah I'm just using it at home but I bet it has many uses like that. I saw another video on these that takes it to another level and fixes many of the issues this design has. Instead of using one filter on the front of the fan you can take 2 filters(still 20" high to match fan size but whatever width you want really) and create a triangle in front of the fan with them. Then seal the top and bottom with a piece of carboard cut to size. This is a much better design I think. It gives the fan room to "breathe" and doubles the filter surface area so it is easier for the fan to push air through. Less air is blown back away from the filter and wasted.

[@TCSC47]

Yes, our air purifier clearly shed some material which we could smell when it was first switched on. Then after a day it was fine.

[@jerrycross1829]

Works the same as a house furnace filter

[@dustjunky2000]

A standard box fan fits well with a 20x20x1 I tape together 2 filters to make a 2-stage air cleaner that I put on the intake side. 1 MERV 8 on the outside, and then it pulls through a MERV 13 on a couple 20" box fans at each end of the house. Our allergy symptoms have been noticeably less frequent, and we don't have to dust nearly as often. Even when we do, there is very little to be found in the house.

[@usillyrabbitu]

I made DIY air purifier during last year's California wildfires and it really helped, but I put the filter on the back. With the awful, awful conditions from current fires, I bought two more box fans and the highest rated filters I could find so I can have 3 running in my home. I don't have an air quality monitor, but I can say that the filter I put on last week was completely gross and trashed in less than a week. And the air in my home doesn't smell like smoke, so it certainly does help some.

[@FredoFreedom]

Thank you. I built one and it does seem like the air is cleaner. I occasionally get asthma attacks and this has helped.

[@YoMama9021]

FredoFreedom you can’t occasionally get Asthma.

[@FredoFreedom]

@@YoMama9021 I meant asthma attacks. It reduces frequency of asthma attacks and I need an inhaler less often.

[@silviaculell]

I'm not sure why other window fans have become such pieces of garbage kzbin.infoUgkxGjG43--gYqIoT4Xkur2PqCrtbKwTv2h6 but this one definitely is nice. It's quiet, it has buttons for different functions that you generally don't have to keep pressing over and over again like some of the others, and the remote is a nice feature. Still, button simplification could go further to single functions for each and every one, but it's decent enough. It's a very quiet fan, the quietest window fan that I have ever had, and that alone is worth the extra money over the cheaper ones.

[@rlund3]

I have used this system for 10 years. It is great for saw dust also. In 10 years it has not overheated the motor. For sawdust I use 2 filters. a low merv for the coarse particles and a higher merv a

[@shauns5278]

I know this is an 11yo comment and you may not even have this account anymore but what merv rating do you use for your pre-filter?

[@rlund3]

@@shauns5278 I am now using 4" filters with a merv of 13-15. I run my fan constantly and the filter lasts almost a year.

[@johnparis6233]

Do you set it up where the fan was blowing air OUT of the room through the window? Or blowing fresh air (with the filter) into the room?

[@locuscades1906]

Did this in my old apartment, breathing ended up being much easier.

[@123idontcareok]

Placebo

[@jasras5003]

@@123idontcareok Cool - you tried it with a particle counter? Do you have a link to your findings? It's weird because there are scientific studies on this that prove a fan and filter removes particulates from the air. Can you provide a scientific study that says it's placebo?

[@kingtrance6826]

@@123idontcareok - Your life is a placebo.

[@johnparis6233]

Did you set it up where the fan was blowing air out of the room through the window? Or blowing fresh air (with the filter) into the room?

[@lucarchive]

My right ear sure loved this video! Great production quality, guys!

[@robertmarder126]

I am currently using a MERV 10 filter on a basic box fan with good results (attached to the rear, not the front as shown in this video). I'm observing around 30% airflow restriction compared to no filter. A box fan simply can't generate enough pressure to operate a MERV 13 filter as shown in this video without experiencing a massive airflow restriction. Nor can most home central air systems for that matter. Too much airflow restriction means you are wasting energy and burning out your fan motor creating a fire hazard. If you decide to build one of these systems as shown in the video, I would strongly recommend you select a filter with a MERV rating less than the MERV 13 shown in this video.

[@seigeengine]

Be careful. It's easier to detect if it's working with the filter on the front, as you can feel the air being blown through the filter, whereas on the back, it can be harder to tell how much air is going through the filter vs. being sucked in the front. Incorrect. Air resistance is related to filter surface area. The better the filter the higher the surface area needs to be to compensate. I would strongly recommend not giving safety advice when you don't know what you're talking about.

[@damnarse]

What an incredible video and service to allergy sufferers. Thank you!

[@chrischiachingli5159]

when I see a good idea I feel like I want to hug someone.

[@JeanneCulbert]

When I read most of these 'ideas" , I wanna kick bitch slap someone!

[@d.colbert6869]

@@JeanneCulbert Me too!

[@BoomShard17]

I hope you've kept hugging 6 years later!

[@TehTechExpert]

Keeps my home dust free I found one of these fans at a garage sale for like $5 got one of these HEPA filters put it on both sides let me tell you I have a smart switch every day for about 30-1hr minutes it turns on and so far one month now my home is way less dusty I can tell from dust all over the home has been reduced

[@davidmendez4209]

I was planning to purchase an Air Cleaning system, after I saw this presentation I changed my Mind, Thanks!!!

[@wfdTamar]

Another method is to cut the filters and lay them on top of a split system air conditioner. Works really well. A flaw of the commercial air 'purifiers' is that they don't actually circulate that much air that is very far from them. Yes, if you test the output like in the video right at the outlet you'll get clean air, but then go to the other side of the room and test. I bet even after many hours of the purifier being run there would be little difference.

[@whit2642]

I must be a genius to have discovered this right by myself months ago. Lol. But really, my husband thought I was so dumb. Can’t wait to show him this 😂

[@pokermel]

lol what did he say

[@supa4ys843]

Not really a genius move when it's just plain common sense lol

[@cIeetz]

if ur husband thought u were dumb than hes kinda silly

[@cIeetz]

@@supa4ys843 if its common sense why doesnt everyone do it. thtas what makes something common sense, it being common. ive never seen any1 do this

[@-kepha8828]

I just did this. Box fan at walmart cost $20. The 20"x20" 2500 (merv rating =13) hepa filter cost $23at walmart. I attacked the filter to the fan with zip ties. I also put the filter on the back of the fan, not the front like this guy suggested. Works great, total cost was about $45-50 dollars after tax.

[@honkbeforeitstoolate587]

Has your box fan air purifier held up after a year of use?

[@-kepha8828]

@@honkbeforeitstoolate587 it held up, but it was NOT efficient for any type of larger room, and its loud. I also had to get a lesser filter, because the better filters (that filter out more particles) could not circulate the air. So overall, it was a short term solution, not a long term, in my opinion.

[@UtwoBed]

Would it not be better to place the filter on the intake side of the fan to pull the air in through the filter in the same fashion that all air handlers operate? he way you have it set up the fan would tend to disturb the particles on the face of the filter and even blow some of them back out.

[@workingfolk]

Good, straight-forward advice which just saved me a ton of money over buying an exensive air purifier. This is the kind of advice that is apprecated by all but the smallest -minded of people concerned only with a person's apppearance.

[@jafinch78]

Might help to use a thicker filter and higher MERV rating if you need. You can probably make a few if you hunt around for free or used fans like I noted in my video I made about the one I made... since was surprised so many don't show using a 2" or larger higher MERV rating filter. kzbin.info/www/bejne/i6mqkmSVmct6rLs

[@jeanellis1751]

Thank you, I wish I could have known this before buying my air purifier. I did not spend that much but I sure could have saved at least $20.00, and now I can make a homemade one as well, thanks again!

[@DEATHOFTHECLOUTCHASERTV]

*Who's Here in 2019?*

[@skramzrave]

@Silly Goose FICK YOU U MICHIGAN PEACE OF SHIT! WHAT THE FUCK ARE YOU DOING IN MY GODDAMN OHIO STATE COMMENT SECTION. See you tommorow at noon (:

[@skramzrave]

@Silly Goose im here what about you? Ill message you back when we win EDIT: touchdown already, fuck good job. You guys missed a extra point so. Ha. In ur face EDIT 2: TOUCHDOWN OSU! Guess who got the extra point mwahahH. EDIT 3: GODDAMN. Thats a 35 yard pass touchdown 6-14 hahHaha EDIT 4: good touchdown MICH i see you i see you. 13-14

[@skramzrave]

@Silly Goose NO FUCK YOPU [e] wd wdwd

[@skramzrave]

@Silly Goose what is that some 4chan crappypasta

[@mrspook21]

December 10

[@CelinaBorjaNCMA]

Thank you for remembering the "working class" people. :)

[@carolmielke8831]

Asfar as I konw this is the best pirce: bit.ly/2BVvMG1 Its gotta be besst priice! ) kzbin.info/www/bejne/oXmYcoOtlLh_i7c

[@SteelBuckeye]

Aka Toledo wolverines.

[@Professorsnype]

GearHEAD92 😂

[@linkinparkrulz2275]

@GearHEAD92 Or people who just don't want to waste money?

[@Theresalwaysmoneyin]

The Horror Archivist all of the above

[@jalenheir]

You want to put it in front of the fan..fan blades collect dust and debris which if you had filter behind fan the blades would recontaminate the air..Very mildly but still..plus works better on motor..push air instead of pulling air and wearing and possibly overheating fan motor...

[@cIeetz]

You can get more pull out of these if you filter the back side and tape the corners on the front so theres nowhere for dirt to suck in the front, only having the circumference of the blades surface area exposed ( if yours doesnt come with plastic covers like his does on the corners )

[@frederickkeeslar1761]

Having grown up in Michigan I can say this is the most Michigan answer to a problem I've seen.

[@fozzibab]

Could you update this? It's 7 years old. A new one would be awesome.

[@anitataylor4287]

Why

[@PaulBaughman2142]

change the filter. i used plastic shipping tape to attach my filter.

[@DJSilverSoundon1]

its amazing how we even survived in the 80s.

[@lonnettedouglas5688]

80's? Try the 70's! We slept with windows open no screens, brooms only and no vacuums, hanging clothes outside to dry AND riding in pick up truck beds. Life was AWESOME!

[@nizammahamood5909]

Life expenctancy was less tho

[@reeseriley225]

Well the air was not as weaponized then lol

[@20xx-mm-dd]

I grew up with bad asthma in the 80's, I'm glad I have the means to live in a place away from diesel fumes now.

[@phatguysrule]

The air was cleaner in the 80s as well...

[@VintageCollections]

2011: Cool 2020: omg this is so amazing!

[@pettypatty329]

hahahahahahaha!!!

[@jafinch78]

2022: Other than the inflation when looking at the price approximately doubling, if not more than. Thankfully, you can find an old box fan used and restore most likely with some oil to lubricate the bearings and not having to clean much. I'd still clean and decon. Amazingly, I've even found free furnace filters on more than one occasion... though only the one time the 20x20 and the other crunched a little during shipping 16x25x4... so requires some more tape and cardboard. :-) Maybe I can make a video regarding... seems like a plan. Off course... I just checked and the best are MERV11. HHhmmm... maybe time to replace the filter?

[@waleyefish9026]

I did it years ago, it works! Just pay attention to the air flow when attaching the filter to the fan. I used duct tape. The higher the Merv # on the filter the better. I wouldn't use less then 10..That's up to your budget.

[@Travis141123]

I use the Oreck XL units. They can be had for $20-30 off Ebay. Clean the element every week or so, replace the motor bearings ($8/10pcs Amazon) when they get too noisy. They run 24/7 for years.

[@Agent5061]

You the real MVP

[@garjo8970]

i searched and only vacuums come up. what do you mean?

[@Travis141123]

Oreck XL air purifier @@garjo8970

[@dontblink9065]

How do you know the reduced particle count is not because of the high speed with which the air flows, that potentially might interfere with the accuracy of the sensor!??!!! 🤔 I'm not doubting the filter assembly itself though!

[@kingwaffleton1774]

Can build a great ad hoc air purifier, hasn’t discovered stereo audio yet.

[@indigo2iris2010]

I thought back of fan seemed more logical, but I followed docs directions, and am tickled pink that my daughter's room smells like fresh air instead of a truck stop bathroom. Results are immediate. Let's see if her headaches stop....I also bought a $20 filter that's FRPA 9, not HEPA. might have missed the boat on that.

[@rynhj]

+April Harley could you please tell me how is the filter working for you now?? my 4 years son has breathing issues as we have birds nesting in the building and i cant afford an expensive air filter, was thinking to try this out!

[@indigo2iris2010]

+Eng iman I really liked the results. I got a box fan and 20x20x1 filter--most expensive they had. About 40 bucks for both, plus duct tape. I taped the filter to the front and let it run. From 9/29 to 10/9, the filter turned almost black. Daughters headaches and sniffles are gone. Room smelled fresh. Replaced with a cheaper filter, but I'm going to go back to more expensive one. Best investment ever.

[@rynhj]

April Harley thank u very much for the reply...now i got the motivation to make it.

[@GrizzlyUrsusArctos]

What a great idea! I have a major dust problem with two large dogs coming inside from dirt yard. You just saved us. Thanks!!

[@rrgardner79]

I've been doing this for some yrs now but I put the filter on the back end of the fan. This keeps the motor and blades from being filled with bad particles and dust. Which make the fan last longer and rotate effectively

[@decifal]

That counter started going down before the fan was even turned on... Apparently just opening the container of the filter makes the dust decline lol

[@Alvin-1138]

Electrostatic charge- but maybe some marketing person will use that as a selling point!

[@dazedconfuzed6]

50% reduction of particles according to the scanner before the fan was even turned on. Either the scanner was broke or that was one hell of a filter that didn't even require the fan to be on to work.

[@nameprivate4287]

I noticed that also !...LOL

[@miapia7229]

So is this bull? Does this work?

[@jasonbourne772]

Nia J It works. Just make sure to seal up the edges to the best of your ability. The reading was off because the guy didn't wait for the sensor to stabilize for whatever reason. Just make sure to get a decent fan (because the motor will be your failure point) and to seal the edges. Filter behind the back won't be as effective vs the front

[@FORMERxZOMBIE]

Thank you Dr. Jeffrey E. Terrell, University of Michigan, thank you so much! This gives us poor bastards the chance to take care of our partners.

[@chriswestgate4934]

I tried this out. I took the suggestions from the comments and taped the filter to the back side of the fan instead of the front like in the video. I noticed however, that with this setup, the strongest suction comes on the front side of the fan in the corners. To test this out, I put a note card in front of the corners to see if it was being drawn in and sure enough it was, whereas on the back side, the notecard wasn't sticking as strongly. To try to counteract this, I taped off the front corners as well. That improved the suction a bit, but I'm still not very sure thats it's working so well. My allergies don't seem to be improving and I actually think it's stirring up more dust/pollen than without.

[@jafinch78]

Best to use a thicker filter to increase airflow like I did and ideally better than MERV13 though whatever is suitable for your allergens capture to be filtered: kzbin.info/www/bejne/i6mqkmSVmct6rLs

[@brucegavin7614]

This is a straight forward presentation, even though the presenter is wearing a lab coat in an attorney's law office library. Thanks for demonstrating with the particle counter meter. This validates the presentation, and I ignored the lab coat and books.

[@dasse1588]

I tried this on my ceiling fan. But it didn't work. It Sounded like a helicopter. So that was kind of cool.

[@missartist123]

Dass e 🤣

[@theanarcho-luthierist2882]

try dangling a filter from each blade, and running the ceiling fan on low speed...

[@jaygames1980]

We did this inside during the wild fires and it works awesome.

[@chrisbrown18andup]

My left ear loved this video!

[@MrVegeta450]

lol I thought it was my headphones, but i could only hear out of the right

[@tohotama1212]

+Christopher Brown lol so funny bro.

[@matthewbartke4424]

Your speakers are backwards.

[@liveleaky7571]

Right ear

[@ListeningPoint]

Your headphones are on backwards.

[@noneofyourbusiness4071]

I wish i could post a pic here. I did this in my very small apt and OMG the difference is incredible. Saved me tons of money too. Thank you so much. Im going to buy another box fan and do the same thin in my bed room.

[@andrewharmon7929]

I have 2 of the IQ Air units. They are fabulous. What is really fabulous is that I have been building my own pre-filters out of Filtrete furnace filters for 20 years.

[@MrSaltnvinegar]

Can't even find a Box fan in the UK.

[@GKMusik1]

I know right!>? If/when you find a hepa filter that size get 50 quid ready too! shame :(

[@decathlete2000]

did u find after all a box fan and hepa filter in the UK?

[@GKMusik1]

nope!

[@richcheema]

I couldn't find a cheap box fan in the UK so I used this air circulator to do the job. Just buy one of the HEPA filters made for the proper units and place it at the intake of the fan. Even though the fan itself is circular I just used a box to house it cut out a square to accomodate the square HEPA filter www.amazon.co.uk/Prem-I-Air-Circulator-black-Ideal-office/dp/B01276V56W/ref=sr_1_sc_2?ie=UTF8&qid=1483902276&sr=8-2-spell&keywords=air+circulatore

[@iPhone-wd4qw]

UK is almost always cold (?).. Who would start a company of fans and air-conditioner there to lost money? :-o

[@colossaltitan3306]

Put the filter on the outtake(front) side. Just like the guy in the video is doing. Fan blades draw in air from the front as well as the back. You'll be drawing in dirty air from in front of the fan if you put the filter in the back.

[@edeaglehouse2221]

And you'll be pushing dirty air out the back if you put the filter in the front.

[@chrisg7336]

Holy crap this works great! I can breath again. Just make sure you put the furnace filter on the INTAKE side of the fan. Awesome...

[@seanwhite7532]

I did this these last two fire seasons to keep smoke out of the house. It really does work. My screen door has a 20 x 20 screen in it, so in went the fan blowing in, with the filter, and open a window on the other side of the house. Got the house from 80 to 60 over night. No smoke. Ruined the filter fast. Anyone who is worried about inside air bypassing and going in from the side can avoid this by cutting a cowling out of cardboard, 20 x 20 OD by about 18 ID, circle, the approximate size of your fan blades.

[@seanwhite7532]

@glensarahs Sure. You have to filter the air coming in the house. You can either put the fan blowing air out of the house and filter the air in a window drawing air in, or in my case, the filter goes right on the fan blowing in, creating positive pressure, and open a window on the opposite side of the house for the air to exit. the fan creates enough air movement that smoke does not come into the open window.

[@pcaetano7527]

there are a bunch of DIY filters like this on utube but this one is the best because he proves it with his science instrument.

[@visionofmalkav]

Due to inflation this is now a $75 build

[@Deathswalk]

I love KZbin university!

[@NPCSN]

Deathswalk You should have your bachelors now! Congrats on 4 years! 😁

[@cheapmovies25]

adding a pre filter will extend the life as well. i have a few of the cheap holmes hepa type purifiers i got at target. they are like 50 bucks, but the filters are 30 each and the pre filters, which are just black carbon based type, cost 20 each. the hepa lasts like 3-6 months, and the pre lasts 6, but are washable up to like 2-3 times. the pre filters i just get at home depot and cut them to fit, you can get a 5 pack of the best ones for 10 bucks. and the hepa filter, they have cheap ones on ebay, but i tend to just stick with the real ones. i get the smoke ones, as that is the main reason i need one, and they are 20 at target. i'm sure you could cut one of these into 4 that would fit though. just would take some working around to get it right and working good. idk, they are nice and do work pretty well, especially when i grew some organic blue oyster mushrooms, but can be expensive. i find that once it gets dirty, i can clean it in bleach water and soap mixed with baking soda, then rinse and let dry in just clean pure water and a little baking soda, and it works for another 2 months. by then you have to change it for sure!! thanks

[@tickyul]

mike smith I do a multi-stage prefilter and run the ionizers quite a bit. I make the fine-filter out of paper towels, about 4 layers.....not as good as HEPA, but it catches a LOT of junk and costs pennies to make. I doubt if I would buy a air-purifier that does not have an ionizer.......this feature really gets a lot of junk outta the air.

[@rickrude6301]

mike smith I would not use another pre filter with this box fan and furnace filter. It would just be redundant, reduce air flow and put strain on the fan motor.

[@cheapmovies25]

i know, since i wrote that, i just stick to brand items made for the machine i got. it seems to work out better in the long run.

[@tickyul]

Rick Rude Most electrostatic pre-filters offer very little resistance to air-flow......and they help clean the air a LOT...and also extend the life of your expensive main-filter.

[@2DReanimation]

Yes, if using such fine filters such as Hepa for air, or reverse osmosis for water, pre-filtration is such an obvious thing. Economically and filtration-efficiency and effectiveness

[@haileymills864]

When I couldn't afford Air Purifies, I used this method to trap Mould spores that were in our house. Not sure if it made a difference however my family had to try something as we were all sick from the spores

[@murdock493]

I have the same expensive air purifier you tested first. Thank you for validating my purchase.

[@awolff3381]

is my math off or does that not seem to be a 90% reduction

[@JurassicJolts]

Your math is off

[@VicDeHaven]

This video is a breath of fresh air (hmmm). It's great to see a physician that seems to be more concerned with our welfare than the ALLMIGHTY dollar. A great proactive start towards a friendlier, kinder, socialist society. :-)

[@lajoswinkler]

Maybe, one day, USA will join the rest of the developed world.

[@pleaseexcusemydearauntsemi9543]

We can help each other out without being socialist!

[@Rextrent]

The people pushing socialism are interested in themselves and the result will not be good. Honest teaching has been replaced by an imposter who pushes Liberalist propaganda. Just the facts, ma'am with friendlier, kinder honesty. That's better than flattery and a bald-faced lie anyday! You're welcome! Do As They Say, Not As They Do.

[@seigeengine]

If that was the case the USA wouldn't be suffering in ways the rest of the developed world isn't. And as someone who supports socialist programs like welfare and free healthcare, I'm thinking about the people who really need it, whereas I aspire to not do so. The simple reality is it's you who are thinking selfishly, and are upset at the idea of paying more taxes.

[@pangrac1]

The more books you have the more scientist you are ;) Anyway, thank you for this video! This is really helpful!

[@miksUSA777]

Appreciate the Test. Clear, Measurable and evident of it effects without the Sales Talk. Thank you

[@JumpingWatermelons]

Thanks. I make these for my home when I live in a part of the world with dirty air. I think it makes a big difference

[@gcraneorigami]

My right ear enjoyed this

[@AirDyran]

+Gavin Crane which sucks, I prefer left ear sound, it's more crystal clear.

[@zes3813]

+AirplaneRandy wrg

[@107EvilLink]

Gavin Crane lol thanks for this comment, i thought my headphone crapped out XD

[@inertiaspinner555]

The HVAC Cabal needs to silence this guy by any means necessary

[@ramrodnj]

What’s the plan I already bought tickets too Michigan I’m at the point of no return

[@inertiaspinner555]

We rally at R.E. Michel’s and launch at dawn 🤣

[@i.p.freely2501]

Wait..... I find it easier to fix stuff for smart people.... unless they are an engineer...then we lynch.

[@egeniojaramillo9048]

HVAC really has nothing to do with air purifying. Heating, Ventilation, Air Conditioning, or HVAC for short. Notice not one of those words says filter or purifier?

[@satrioekowicaksono7452]

@@egeniojaramillo9048 it's included in Air conditioning.

[@rynhj]

don't you think that if i us ethe ventilation fan with the filter at the back is more efficient!!!

[@dennisjohnson2726]

+Eng iman That would restrict the cooling air going to the fan. There is quite a bit of sir resistance from these hepa filters.

[@7GtwNYkHYs]

Thanks Dr Jeffrey Terrel and University of Michigan for convincing me to build a low cost air filtration system like demonstrated in the video. If I could afford a high end HEPA filter I would but unfortunately the best I can do is a box fan with a filter.

[@OldSneelock]

Whether the filter is on the front or the back makes little diffrrence to the efficiency of ythe filter in removing particles. As long as air is moving through the filter the filter will strain out the particles. In a normal room environment the fan blades will not pick up any more dust than a fan without a filter. I use a box fan and cheap furnsce filter to limit dust in my shop. There I put the filter ahead of the fan to protect the fan motor.

[@ShaineMata]

This looks like a good temporary air filtration solution until my wife and I find a good alternative, on which we agree. I'll likely put the filter on the rear. #tlacuachada

[@trublgrl]

This simple, $25 DIY filter consists simply of a blower and a filter. "What does the $800 unit consist of?" A blower and a filter. And some LEDs.

[@rdvgrd6]

Most expensive air purifiers also have active carbon filters (to filter out air born bacteria and odors) as well as sensors and chips that permits to automatically adjust the fan speed in relation to how many particulars are in the air.

[@j.s.3414]

An $800 filter has that...as well as ionizer filter, carbon filters, and alot of times a filter to extract odors from the air.

[@EduardBirkaya]

Wow, he looks so smart and like and full of authority that I can trust... labcoat and a tie! glasses too! (good video btw :-P, just joking)

[@rla1000]

I did the same in my shop, except I taped the filter on the input side of the fan, and completely taped it with masking tape for a full seal. I just turn it on low speed and it is highly effective. If you think you don't have saw dust and other particulates floating around, the visible dust collected on the filter will convince you, not to mention there is a noticeable improvement in the air that I breathe. The fan was $19 and HEPA-rated filter $19. With the filter on the input side of the fan, the "dust side" remains accessible and every once in a while I simply vacuum it clean, I don't have to remove the filter to do so. I recently added a second fan and have both fans running when I am doing a lot of sawing, routing, or sanding.

[@rdyvptnm2014]

Do you have the HEPA filter link ? I couldnt find the one that was shown in Video

[@rla1000]

@@rdyvptnm2014 First note that there are three rating systems: MERV, the national/international standard, MPR, which is 3M's own rating system, and FPR, a system devised by Home Depot. They use different number ranges but can be compared, they all do the same thing. For example, MPR 1500-1900 = FPR 10 = MERV 13. Lots of websites explain these. However, glad you asked because I goofed on the HEPA rating. I thought I had HEPA efficiency, but not quite. I have a Honeywell FPR 10 rating ($19 at HD), which equates to a MERV 13. Only MERV ratings above 16 meet true HEPA standard. The FPR 10/MERV 13 still filters fine dust (as small as 0.3 microns), smoke, and many bacteria and viruses depending on size. Important to me is that the MERV 13 rating (FPR10) filters out lead dust, although I use 3M N100 masks plus other controls. You should just research on your own, too much info to put here. I don't know where the MERV 13 filter came from in the video, but the Honeywell FPR 10 is considered equivalent. You can find furnace filters at various ratings at any hardware or big box store (Lowes, HD, etc.). Here's a HD link. If it opens the same way, there's an FPR 10 and FPR 12 listed first. www.homedepot.com/s/furnace%2520filter?NCNI-5

[@rdyvptnm2014]

@@rla1000 Thankyou for detailed explanation. I found this link helpful..www.airfiltersdelivered.com/c/merv-mpr-fpr-ratings

[@Kotaztrafee]

I thought this was my idea so I tried it before seeing this video. I can tell you that a box fan does not have the power to have such a restriction placed upon it and my fan was struggling to turn. I suspect if I had kept the filter on the fan for long the motor would heat up and burn out in a short time. This is probably why what seems like a good idea is not a good idea and one can not find such a thing on the market. After watching more videos I have come to the conclusion that the cube style of filters might work and am going to try again with a better fan than a Lasko.

[@goud2488]

Update?