The Best Air Purifier Is A $150 DIY Option
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- čas přidán 3. 07. 2024
- The Corsi-Rosenthal box is the best air purifier we've tested-and it's one we built ourselves. We're saying that having tested 26 in total. Just how can this ugly, loud, extremely DIY box of filters be the BEST air purifier when we've got some sleek Dysons, portable Levoits, and much prettier, cooler boxes of filters?
Chapters:
00:00 Intro
00:37 What is a Corsi-Rosenthal Box?
04:40 How We Test Air Purifiers
07:35 Air Purifiers In Action
08:45 Conclusion
For more details about our testing process, check out our article:
www.rtings.com/air-purifier/l...
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Physicist here: I'm a great fan of your work, and you have become my reference when buying and suggesting monitors. The work you did here is quite interesting, but the methodology can be improved.
First of all, I would wait 5 minutes between the introduction of the smoke and the moment you start the machines: this way the smoke can spread uniformely in the room and the results are less affected by the way the smoke enter into the room. In addition, you would also have a more accurate reading of the starting amount of particles, which you should use to normalize the results.
Last, but not least, every time you perform ANY kind of measurement, you should repeat it at least 3 times (or even better 5): the first measurement gives you a value, the second one tells you the accuracy, the third one tells you wether the difference between the two is due to stochastic noise, or you have some problems in your methodology. Of course, the more measures the better, but you need to balance the accuracy of the measure with the time you are willing to spend, and 3 measures are usually enough to know if you need more. In addition, would be nice to see if 3 or 5 puff of smoke are enough to see a drop in the performances, giving you an idea of how long the filter would last
You have made the assumption that they don't do this already. You know that how?
@@kidShibuyago away
While the point about waiting five minutes is a good one, and pretty fair, I do think it's worth considering that having the purifiers on _while the smoke propagates_ helps determine the quality of the fans, since, as we saw in with the Dyson bladeless, some of them can actually prevent air from passing through the filters, and in this particular test that's a really useful data point to have in order to determine just _why_ certain purifiers which should have a significantly higher theoretical performance don't reflect that in practice.
Regarding the multiple tests, that's standard M.O for any kind of technical testing as far as I'm aware, it just seldom gets brought up unless explicitly relevant because it's so well-known that in most cases it'd be comparable to dead air. That said, I don't think anyone who's working on doing analytics like this professionally is just doing one testing pass and calling it a day, which is a big contributor to why testing things like this can be very expensive and time-consuming, and a big reason why you should go give RTINGS your money, because they do good work!
@@butterscotchpanda when they described the monitor tests they specified the number of repeated tests and how they combined the results; here they didn't say anything about this, nor did they mention it on the article on the website. They didn't even mention a variability from test to test, which is VERY indicative of just one test being performed...
The 5 minutes delay has 2 different functions: having all the system starting in more uniform conditions, and being able to accurately record said conditions, in order to remove any leftover difference during the analysis.
Christ, mate you’re not doing a public lecture, why the pretentious writeup?
You guys really came out with this one day after I purchased an air purifier from Ikea
There's still time to return! 😂
You got ripped off. Plus these builds are often better for your energy bills and vastly more efficient depending on fan purchases. Thus over 4 or 5 years IKEA will rip you off even more.
Return it quickly 🎉
This has been known for a few years, ever since Covid.
would have been nice to see a comparison with one of the bigger units (eg. iQair healthpro) that would be more similar to the dyi solution in terms of ugliness and footprint.
Following their toaster PhD study, they come to deliver another unexpected banger.
Hahaha we always try to deliver, thanks for watching! 😄
Please test the CR box with Pc fans! they are much quieter and consume way less power. You should be able to find more about them easily. The 5 fan and 9 fan versions are very popular. They usually use arctic p12 fans. There are also companies selling cr inspired air filters with pc fans. One of them is Clear Air Kits. Regardless, its a very good video!
This! The reaon for Arctic p12 is that they offer high static pressure. Using models with low static pressure (i.e high flow or silent variants) will have worse results, since those will struggle to overcome the filter resistance.
I've literally been doing this for many years now! And I didn't invent it, someone told me to do this that had also been doing it for many years. Also, if you have a forced air system in your house just find the cold air intake and place these filters over it and tape them in place to seal all the holes around them and it will also clean the smoke and other particulate out of the air of your entire house. We did both of these things for many years during the wildfire seasons because without it the house would be filled with a haze and our throats would be on fire. Also, it's not necessary to use 4 filters unless you need the capacity. Even a single filter the same size as the box fan taped to the back of it (intake) will work great for several weeks even with heavily contaminated air before it's clogged up and needs to be changed. We break these out every year during the wildfire season here in Washington State because without it our throats feel like they are on fire and our eyes burn. People have been doing this for a very long time though.
PS: Credit to Adam (aka. KevlarCondom) for buying me a box fan and my first Hepa filter showing me this technique a long time ago.
You guys make me want to work at rtings.
I been sneezing my buns off in my bedroom, and now I'm considering making the ugly boy, thanks guys!
You might also want to check out Clean Air Kits.
Glad to hear we've been a good inspiration! 😄
If you buy the pack of filters at Costco for $40, adding a $30 box fan can make the CR box build cost far below what you quoted in the video.
Even better! It seems that pricing is different depending on where you are in the world!
@@Weaver_Games Actually, je suis 🇨🇦, and yes, you can find the components for cheap.
Yes. Cheaper
I would love to see some testing with 120mm computer fans strapped to a filter. They are optimized for static pressure to push air through radiators. I would recommend a push configuration versus a pull configuration, but testing both would be great. A cheap fan would be the arctic P12. If you use the PWM version they are even speed controllable. A high end option would be the Noctua NF-A12X25.
Would be great to also compare replacement filter costs and expected lifetime. The more filter surface area (given a fixed volume of air being filtered), the longer the filter will last. Of course the finer the filter, the shorter it will last. Some manufacturers go with the razor and blades model, and make minimal margin on the purifier and extreme margin on the filters.
The homemade box would win across the board. Furnace filters are made in such massive quantity that nothing custom for a purifier is going to beat that economy of scale. You can also buy the filters in large 10+ packs which knocks the price down even further.
I have no idea how they managed to spend $200 to make that box though, the fan shouldn't cost more then $30, and the filters are around $25 each if you buy them at full retail price.
@@zncon Everything in Canada is ridiculously expensive, you have no idea.
@@zncon They also came up with the idea that this was invented during covid by 2 engineers and not like 100 years ago. Tons of youtube videos of these designs predate covid lmao.
@@gg-gn3re Oh boy that's a whole separate rant that I wasn't going to get into, but I hate that two people just slapped their names on what has been a known 'box fan hack' for decades.
@@zncon Yea I have a wooden one with 3 slots for filters and wheels on the bottom, hard top (so I use it as a table) and a blower/ air mover fan inside. Way higher static pressure/vacuum/air flow... and it's like 15 years old lol
There are prettier designs available from "The 3d handyman" youtube channel. He has also done testing on a bunch of filters and fans, and found large differences between brands.
I’m curious about the PC fan versions of the DIY air purifier as well. Really surprised someone hasn’t done up an ESP32 controlled version for basic stuff like timers, ambient lighting, or other “make it nicer” features.
As a hobby mycologist, I make all of my own laminar flow hoods. They work great for a fraction of the cost of a commercial brand.
You guys made this at the precise time. You just saved me so much money.
The better DIY alternative to the box fan design uses a bunch 120 or 140mm high static pressure PC fans. Uses the same filters. Cheap to build, cheap to run (pc fans use
This is really neat, and I love the DIYness of it. As an exceptionally lazy person, I'd like the DIY option more if it could be built with a frame that the filters could sit in and more easily be replaced without having to fully retape the whole freaking thing just to replace filters.
I've seen people use PC fans instead of box fans. There is also at least one company that makes fancy schmancy looking frames for Corsi Rosenthal boxes that don't look like actual trash.
I don't need an air purifier, but I'm still really glad YT recommended this video to me. Love the methodology and style of these videos.
Too bad this design got named after Corsi and Rosenthal when Neil Comparetto was the inspiration for them.
A couple things: how would 4" thick filters do vs the 1"? More filter media area means theoretically more airflow and the ability to run quieter or use smaller dimensions iso-CFM . Related to CFM would be different box fan types. There's an optimal static pressure and CFM fan for the best noise normalized filtration efficiency for a given MERV and it would be really cool if a review site could find that out.
The problem with 4" filters is that they blow up the economics, they are WAY more expensive than 1" filters.
@@dtemp132 Maybe. The video is about the best performing air filter. The DIY box just happens to be fairly inexpensive. The main complaints are that it is loud and ugly. The ugly could be fixed pretty easily but the loud part offers a few possible avenues to look at like thicker filters for slower fan speed.
Economics wise, a pack of 4 20x20x1 MERV 13 filters is $65. A pack of 4 20x20x4 MERV 12 filters (no MERV 13 available) is $108. I don't know what the area of the filter media is for the 4" filter. All else being the same, it should be quite a bit more which means lower pressure at a given CFM so you can run a fan at a lower speed. As well, they have the ability to hold much more dirt which means longer intervals between filter changes. So if the interval is twice as long, the economics is a wash. I would guess the interval is going to be over twice as long so the economics might be better. But I don't have any data to back that up.
However, the 1" thick Filtrete 1900 has an unusually high number of pleats as Project Farm discovered. The static pressure drop is fairly high but the DIY box has an enormous amount of filtration area so it might not matter vs a single unit for a furnace fan. They might even get higher performance in the lowest number of small particles after an hour test if they used even finer media like the Filtrete 2800. They could compensate for the pressure drop by using 4 20x30" ones and even a 20x20 on the bottom with some legs for a 40% increase in surface area. Who knows, not worth testing for a regular guy but RTINGS routinely tests tens of thousands of dollars worth of TVs, monitors, printers etc so messing around with a couple hundred dollars worth of filters would make for an interesting review.
To me, the key to getting it quieter would be to find a DC powered box fan though and seeing which one has offers the most filtration when normalized for noise. Box fans don't get the exotic technologies found in PC fans like liquid crystal polymers and exotic fan geometries but there might be some out there.
@@AhpgZfoc4s I was thinking about using a much quieter design by using 20cm PC DC fan instead of a box fan for just a bedroom. I would love to see some testing of this concept. Maybe even expanding to a 2x2 square of 20cm fans for a better surface area to noise balance if you did need a larger volume. Automating/monitoring it with a microcontroller would also get the benefits of the much more expensive mass market air purifiers as well.
@@Zyxlian I think that would work. I had a watercooling radiator that used a 2x2 square of 20cm fans and it was very quiet. Plenty of fan controllers out there as well so I think that would be a winner!
I’ve been using a winix 5500-2 since 2020 and it’s been great. It’s surprising how much crap it captures in my bedroom.
The quarterly filter replacement isn’t that much with off brand hepa and carbon filters
You should consider testing the The 3D Handyman kits
I would love to see reviews of some of Blue Air's purifiers. Their purifiers don't have housings but a washable cloth surrounding a ring of a filter. These could be in that middle ground of presentation and performance.
Either way, excellent work with the video and testing!
you can get a bundle of 5 Arctic P12 Max fan for 50$ . wih a 10 buck controller. that could decrease the noise by alot and fine tune more since more control about fan speed.
Also use less electricity. Those box fans are around 100w. Wich adds up when running 24/7
Love the Vid. Just in time for my decision to clean my bedroom air!
Thank you for watching and glad you enjoyed the video! Hopefully our video and reviews can help you buy what you need! 😄
Do robot vacuums and mops next please!!
I made one of these for our class room a few years ago, we're a project based school so we be doing alot of weird plant and chemical stuff which made the room stink. So I got approval from our teacher to build one and it worked amazingly.
Whoops - the particle counts start at WAY over the count limit of the meter you're using. It's missing many of them at the start. This is visible in how it takes until below 100,000/L before the drawdown on the log scale vs time plot becomes linear. It also means the natural decay isn't representative of the actual natural decay. Is the data available for download? What is the size of the room used?
Very curious about the Blue Air filters.
Thx, i will newer check you rating related to air purifiers again!
I was having formaldehyde issues and the big+quiet really did lower them substantially - and I verified it independently with an external standalone air tester (in fact, testing my air was what lead me to buy it lol).
That said I don't live in like a glue factory or something, no idea how it would perform in like a high formaldehyde production environment.
Corsi-Rosenthals are really good but also won't catch ultrafine particles. If you're worried about something like asbestos your only actual option is HEPA.
I know you shouldn't be dealing with asbestos untrained but, for example, my friend lives in a century home loaded with asbestos and his kid accidentally broke a hole in the wall. That's scary stuff, you'll need to quarantine the area and run a HEPA purifier probably for a few days - you also can't just vent it outside cause then you cause dangers to your neighbors.
Finally, you kind of glossed over VOCs. You're right the majority of purifiers have nowhere near enough carbon to capture them. Even the Dyson at the higher end has 900g which is truly not enough. That said there's some units from AllerAir that have almost 24lbs of carbon in them - those things will work wonders on VOCs. And yes, the replacement costs on them are absurd - but if VOCs are your primary concern they're among the only things you can do.
TD;LR - large particle measurements and CADR is a good way to measure the practicality of a purifier for most household use - but there's some specialty cases where I'm of the opinion MERV filtration alone just doesn't cut it.
There are apparently some studies that show the air turnover rate really does make a much bigger impact than HEPA. Still unsure if it changes formaldehyde issues but over the course of running the CR box usually gapped any competition. That was with the good filters on max which makes them nearly as loud as the CR box too.
But I’m not a scientist. Just going off CZcams and other DIY fan makers which might be parroting the same data.
Ok, how is there not a maker project based on the Corsi Rosenthal box that integrates some of those quality of life features, like a air quality sensor, Seven segment display and smart home integration with a low cost esp
Why didn't you mention using quiet PC case fans to solve the noise issue while maintaining same or higher CFM than a box fan?
For some reason box fans do not seem to be a thing in Europe, which makes many of us rather sad...
Check out Clean Air Kits, they use quiet and efficient computer fans.
There are people who make them using PC fans. They are quieter and if you combine 4+ some claim they will perform on par or close.
You can probably find a 3D print shop that makes the brackets and then just need a basic fan breakout that accepts DC or USB power.
looks like something i'd find in a bachelor pad of some health conscious teen. i'm rather content with my Coways. Still going strong and I've been running it virtually non-stop since 2018. Well worth it and it's been a life changer for my allergies.
I would love to see you test the ones from Xiaomi, they are really popular in Europe
They are bad (don't cycle a room worth of air often enough to actually remove enough particles and are quite loud at max speed) & the filters are really expensive.
philips air purifiers are probably the best on the market
You’re also not generating or monitoring for small enough smoke particles. You need to go down to 0.1 microns and smaller.
That would be a nice metric, but keep in mind those expensive mainstream "hepa" carbon activated etc air filters had much worse performance than the diy box.
0.1um won't add much to the conclusion if what is claimed to clean 0.1um (hepa) wasn't able to clean 10um effectively
The Levoit Vital 200S promises 1.27 CFM/$; the Levoit Core 300, without electronics, says 1.4 (140 CFM for US$ 99).
(cfm = cubic feet per minute)
(That's not considering the cost of replacement filters.)
Where I live, One of these filters alone cost $150
Oof, that's rough 😭
I do love to have more data like noise level. And possible noise normilized performance.
Why test an inch away from the wall? I'm pretty sure the devices I own all recommend about a foot from any surface.
If you're going to position the air purifier in a corner like shown, would it make a measurable difference for the corsi rosenthal box if you only have the two "exposed" sides with filters and just a mesh on the sides facing the walls?
Please review the Vitesy lineup of air purifiers. They have some interesting plant-integrated versions and other sorts of portable purifiers. Their selling point is washable filters without performance impact saving on running cost.
👀
Ikea makes a purifier built into a small table (STARKVIND), which makes it easier to have near the middle of the room.
Have you ever tested anything from the Aerus in terms of filtration, air purification and surface disinfection?
since the box fan set up is so good, can we see it with more than 2 secdonds of smoke? like 10 seconds to really pump that room nd see how much of a differance it really makes?
I surprised you didn’t test the IKEA FÖRNUFTIG. It’s great budget option.
That’s a massive cr box , what hvac size filters are you using?
what is the absolute best for smells in an office enviroment?? Please tell me!
If you build this, try to use a high-quality fan and ensure it doesn't overheat. Cheap fans probably use the cheapest motor to get the job done, and adding air resistance in the form of filters might overload the fan and pose a fire hazard.
That's not how fans work.
@@butterscotchpanda Yes, it is.
Sounds like this would be ideal to just store away in a closet and place down in a room while you're out of the house.
Filter replacement frequency and price when discussing this, please.
well it's as if the universe were taunting me. my yearly rings insider subscription just renewed and I was shopping for air purifiers this week and then I see this video pop up. woohoo
Love to hear it!! 😄 Thank you for the continued support ❤️
Wondering if it would be possible to ceiling mount the Corsi-Rosenthal. Would there be a reduction in performance if you could?
Does this also help with allergens?
also I'd love to see info on how accurate the built-in sensors are. most from what I know are useless!
Yes, but an air filter is not a complete solution. It can only remove allergens after they've gotten into the air, where you can breathe them. Removing sources of allergens is still important. Minimizing soft surfaces (furniture, carpets) which can trap allergens helps, as does frequent cleaning (e.g. HEPA filter equipped vacuum).
@@SnakebitSTI it's still helpful afaik. It helps filter the leftover allergens.
The site doesn’t allow for air purifier product review suggestion yet. I’d like to suggest the TruSens Z-3000
We will open that up once we're closer to a time where we'll be buying more air purifiers (30 days before most likely) :) Thanks for sharing!
I hecking want the aerosolized formaldehyde test
If only I could get the levoit vital 200s in the UK
Am I counting five (5) air filters? Also, I cannot find any instructions on Wikipedia? Can someone help?
I always suspected this general result about air "purifiers" and have used the super simple single filter plus box fan for a long time. Air SANITIZERS on the other hand, as in actually killing pathogens rather than just trapping the dust they might be riding on, are something I believe might have potential to be worth buying a commercial product and would love to see tested. Much harder though.
Some white gaffer tape would probably be more attractive than the black tape
When you have a co-host, look at the co-host when they speak, instead of the prompter. It looks much more natural
Wait, are those carbon filters actually pointless? I've been getting them on the cheap IKEA purifier because I have medical cann' flower and it smells and I use both filters and it does make a big difference and the smell and vapour does shift very quickly. I'm now very conflicted, but that's not a bad thing.
It depends. Some are better than others. I bought some Blue Air "Smoke Stop" carbon filters and, IMO, they did absolutely nothing. I also have the Dyson Big+Quiet that I found did actually work against formaldehyde, but still doesn't have enough carbon to really do much for VOCs. That said there's units designed for high VOC environments from AllerAir (it's VERY expensive) but these things run 24lbs of carbon and are absolutely capable of absorbing smells and VOCs from the air.
@@Weaver_Games Because that's all the kitchen extractor fans do that don't exhaust, they have carbon filters to remove smells. Are they esp different?
No. Carbon filters remove stuff these don't, such as odors.
The merv 13 are better for the pollen etc though. usually higher end filters will use both layered on each other.
nice! well I now know what I'm getting for prime day...
It does not look like a great deal of effort was put into researching market leaders in Air Purifiers at all and Dyson was picked as the main competitor for clicks. SmartAir SA600 or Blast, BlueAir, Cowway AirMega series and IQAir should have been compared.
I am disappointed that you did not test the IKEA ones. They are affordable and the filters are not too expensive.
Did not buy and test them.. *yet* we're hopeful to in the future! :)
Hi Abby❤😊
Why didn't you test Blue Air which by many accounts probably produces the most powerful purifiers out there?
I implore everyone to go with the DIY option. The company that made my air purifier was acquired by a larger company and I can no longer buy the filter size I need for the device.
How'd you get to $150 for a box fan and the filters?!
Abby is sooooo awesome! Shes the best 😍🥰😃😃😃
Just don't tell the landlord you drilled a massive hole in the wall xD
1 sheet of paper & a bit of paint before moving out will fix that ;)
9:27 - single filter, not single fan
Nifty
I wonder how the CR box would fare with noise if it used PC fans like P12s
That's what Clean Air Kits has done, they use the much quieter, reliable and more efficient computer fans.
OK seriously guys and gals at Rtings, why not design that duct tape filter with a real frame, with slip ins for the filters, and replace the box fan with a integral fan somewhat like the fan on an outdoor ac unit, then market it for 1/2 the cost of those rip off brands, and have some spare change to give yourselves a raise, and buy a microLED to test.
Review needs to consider the actual HEPA heavyweights - Airpura, Austin, IQAir, and similar. I expect they would trounce the DIY option.
Nah.
First hit for IQAir on Amazon is the HealthPro. $900 for 300 CFM; the Levoit used in the video is $190 for 240 CFM. Also the product description lies, claiming that "ordinary HEPA" filters only down to 0.3 microns, which is not true.
The AirPura T600 doesn't give a simple CFM/CADR, but based on the claim of 2000 sqft 2/hour 8 foot ceilings, I calculated 533 CFM, for $900. That's much better than the HealthPro, but is still 0.6 CFM/$, vs. nearly 1.3 for the Levoit. AirPura C700 DLX is 635 CFM for $1100 -- 0.577 CFM/$.
So neither one compares in cost-effectiveness to the Levoit, which was trounced by the DIY.
@@mindstalkCFM is far from the only thing you should ever be looking at. In fact, think it’s probably one of the last things you should look at. If you really care about air filtration, then the first thing you should be looking at is their certifications for what particle sizes they filter out, and to what percentage.
On that basis, the HyperHEPA filter of the IQAir will beat the CR box hands, down. No competition.
Check out the CZcams video titled "Most HEPA Air Purifiers Are A SCAM (There's A Better Option)" by "Healthy Home Guide" for more information.
@@shubinternet I agree with this. A MERV will work for larger particles, and it will deliver way more CFM. However, if you have specific concerns say with VOCs, Formaldehyde, or ultrafine particles they will do basically nothing. I do agree with RTINGs that most purifiers that claim to filter VOCs have nowhere near enough carbon to do so, but there's some specialty units like AllerAir 5000 D that have a whopping amount (24lbs) of carbon.
In my opinion just releasing a single type of large particulate vapor into the air and seeing how fast it removes it isn't really the end all be all measurement of an air purifier.
I know they say releasing stuff like VOCs, formaldehyde, or hell even friable asbestos would be too dangerous for them to test - and it very probably would be - but this is the kind of data I'd really like to see.
@@shubinternet No. Filtration rate would matter if you were pumping air through a pipe in a single pass. But for a standalone purifier, you end up re-filtering a lot of the same air. As long as you filter a good fraction of the smallest particles, which you do by MERV 13 (50%), what then matters is high airflow.
As for HyperHEPA, I don't trust marketing copy that lies about what "ordinary" HEPA does. HEPA does not stop at 0.3 microns; 0.3 microns is the _worst_ filtration size.
You could probably devise more elegant alternatives to the duct tape. 3D printing, welding, what have you.
Honestly, I'm not so sure about that. Permanent things like welding are out of the question since the filters need to be replaced, and a 3d printed bracket wouldn't be airtight. But you could probably 3d print a bracket that goes on top of the tape to cover it up, or create a complete housing out of wood. But you'd need tape regardless.
No, you wouldn’t need tape. You’d just need to make an airtight seal around the filter. Companies do this all the time when they’re building air handlers for A/C and furnaces to put in your attic or your crawl space. They use simple gaskets and sufficiently rigid and strong materials. You could easily build the same for a CR box, and lose little - if any - CFM throughput on the fan.
That idea has been around since old days of this old house. To say someone invented it during covid is a joke
Please stop saying Corsi and Rosenthal created it, peoples have been making those years before, those 2 just made it more mainstream and gave it their names
cute, but far too big lol
Aaaaaaand you've built it wrong. Go back to the OG design.
Put the fan on the bottom, up on ping pong balls.
And to increase filter life put a fifth filter on the side that was originally blanked off.
Cool insight!
Can we have more OLED burn in tales, please? 🥹