Most HEPA Air Purifiers Are A SCAM (There's A Better Option)
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- เผยแพร่เมื่อ 25 พ.ค. 2024
- In this video, I present a staggering amount of evidence demonstrating that HEPA air purifiers are not as effective as Corsi-Rosenthal Boxes and other DIY air purifiers. I also talk to Wayne Westerman and Rob Wissmann, co-founders of the company Clean Air Kits that sells air purifiers that are quieter, more powerful, more energy efficient, and cheaper than commercial HEPA air purifiers. That's right: you DON'T have to build a DIY air purifier yourself!
Note: This video is NOT sponsored.
This video is a journey. By the end of it, you'll learn exactly how to dramatically improve your indoor air quality by using air purifiers (AKA air cleaners). You'll also learn why you should. You'll learn about a better metric to evaluate air purifier performance so you can never be scammed into buying an ineffective unit again (Clean Air Delivery Rate, or CADR).
0:00 - Intro
1:35 - Research on the health impacts of particulate matter (PM)
3:43 - Why I started getting skeptical about HEPA Air Purifiers
6:12 - Clean Air Delivery Rate (CADR): a better way to measure air purifier performance
7:28 - How can HEPA air purifiers capture virtually all particles, but still leave the air dirty?
10:05 - What are the tradeoffs of the high efficiency of HEPA?
10:36 - Most HEPA brands don't even report CADR
11:05 - Some HEPA brand DO report CADR. Can we trust that number?
11:29 - RESEARCH STUDIES showing that DIY air purifiers (CR boxes) with MERV-13 HVAC filters are better than HEPA
15:31 - Can HVAC filters capture ultrafine particles?
18:08 - Why HEPA efficiency may not be as high as 99.97%
19:16 - Can CR boxes protect us from viral transmission?
20:03 - How CLEAN AIR KITS makes a quieter air purifier (PC fans)
22:18 - How do clean air kits compare to CR boxes and HEPAs?
24:00 - How can clean air kits be safer than HEPAs with comparable CADR?
25:44 - WHICH AIR PURIFIER SHOULD YOU BUY?
27:59 - BEFORE BUYING: how to size an air purifier to a room
29:42 - Wayne's air purifier layout strategy for viral transmission (THE EXHALARON)
31:42 - Are HEPA filters useful in other contexts?
32:09 - Are activated carbon filters and prefilters necessary?
33:29 - CALL TO ACTION
BUY FROM CLEAN AIR KITS:
www.cleanairkits.com/
Scientific research:
Ratliff et al: e9i3r2v2.stackpathcdn.com/wp-...
Myers et al: www.tandfonline.com/doi/figur...
Dal Porto et al: www.medrxiv.org/content/10.11...
Srikrishna et al: www.ncbi.nlm.nih.gov/pmc/arti...
Holder et al: pubmed.ncbi.nlm.nih.gov/36437...
Review of numerous papers: ncceh.ca/resources/evidence-r...
Azimi et al: www.sciencedirect.com/science...
Stephens et al: pubmed.ncbi.nlm.nih.gov/23590...
Chang et al: aaqr.org/articles/aaqr-16-10-...
Pawel Misztal's presentation (the figures about PM and mortality rate): tamest.org/wp-content/uploads...
EPA article: research on DIY Air Cleaners to Reduce Wildfire Smoke Indoors: www.epa.gov/air-research/rese...
Simple way to size an air cleaner (AHAM’s 2/3 rule): ahamverifide.org/ahams-air-fi...
Air cleaner selection tool: cleanairstars.com/filters/
Joey Fox’s amazing articles:
Is HEPA necessary for portable/in room air cleaners? itsairborne.com/hepa-filters-...
CADR is all that matters: itsairborne.com/clean-air-del...
Are extra features in air cleaners necessary? itsairborne.com/how-to-pick-a...
David Elfstrom’s article on how to do your own CADR test: itsairborne.com/how-to-measur...
DONATE TO MY CHANNEL: www.buymeacoffee.com/healthyh... - แนวปฏิบัติและการใช้ชีวิต
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I don’t want people walking away from this video thinking that HEPA filters in general are useless.
I want to reiterate that there are numerous different contexts and settings in which filters are used. The type of filter required varies between them. MERV-13 is sufficient (or even optimal) in many of these. However, as I mentioned in this video, HEPA is necessary in some. For example, vacuums, powered air purifying respirators (PAPR), clean rooms, operating theaters, or nuclear laboratory exhaust.
To add to what I said at 31:42: the Exhalaron by Clean Air Kits creates another context in which HEPA filters ARE useful. I’m referring to near-field source control, minimizing the spread of virus from a sick person to a healthy person. This scenario is different from reducing overall particulate counts within a medium/larger room.
Here’s a video of the exhalaron’s suction in action! th-cam.com/video/EJIK0RPEgeo/w-d-xo.htmlsi=b6DR68vSeDQPX8bI
Can you please recommend an air purifier for a bedroom?🙏
If you use a system that is 100% clean air it would be a partition. So this all makes sense. I discovered long ago that if I wanted better particulate filtering, just let the filter clog up a bit. More and more particulates with be captured. But the air flow will decrease and the efficiency of the furnace will go down too. I'm thinking that electrostatic air cleaners might be one way to go but then you have the ozone problem. The other alternative is to not allow dirty air anywhere in your home. Plastics and synthetics are volatiles. They emit air borne contaminants all the time for the life of the product.
Your presentation is really good and I hope you will continue.
Very glad I found this video. Last week I purchased a Levoit Vital 200S-P as the home that I'm moving into has noticeably bad air quality and has shown worryingly high fungal presence in air quality tests. I decided to test it in my current home ahead of time, and after running it in a particularly dusty 168 sqft storage room on the highest setting for 8 hours I can't tell any difference. Not only that, but the machine had the audacity to say that the room had reached "excellent" air quality within 30 seconds of being on. I can't believe how many online reviews are praising this thing.
As for a replacement, I'll need to find some more reviews first, but I'm pretty intrigued by the Luggable XXL. Thanks for gathering all this data.
I’m glad you found it to be helpful! Air purifiers can certainly help reduce the amount of particulate in the air, but they have limited efficacy against odors. Ventilation is better for that. And source control (removing the smelly material).
Air purifiers can be a good temporary bandaid (among other methods) in homes with higher fungal counts, but if your house has a severe mold problem, they can only do so much on their own. If you need more advice, please don’t hesitate to email me.
I came up with the same idea in 2020 when the California forest fires were raging and ran a whole bunch of tests with an AQI meter to come to the same conclusion that the typical air purifiers are way overpriced for what they do. Glad that more people know about this design now.
As a moderate allergy sufferer I've used HEPA air cleaners, always Honeywell brand which had/have cadrs of 300 or higher. The units have always sounded like small jet engines but I didn't care because being able to breath was more important to me and after years of using them it's a little harder to go to sleep without the noise. I got noticeable relief from them and never questioned their effectiveness until I watched your video. I have an email into clean air kits and intend to buy to compare one or more of their filter units. You should hit them up for a discount code for your viewers.
Been using Honeywell and Holmes larger types for over 20 years and zero issues with air quality. This test is invalid for me
I use Philips air cleaners during hay fever season and the results are great. After turning one on, it takes just a few minutes before I can breathe again.
Yeah, last week we changed the filters on our GermGuardian air purifiers and cleaned our air conditioner filters. I am a major allergy sufferer, and most of my family are moderate allergy sufferers. Until we cleaned the air conditioner filters and replaced the air purifier filters, my pallet was itchy and I was sneezing up a storm. After cleaning/replacing the filters, my conditions quickly went away.
Excellent video, Alex! Nice use and citation of other’s research and data to support the topic being discussed. 👏
I appreciate your support Josh 🙂
good things about DIY ...1, supply availablilty (instore/online) 2, cheaper for the amount of air filtered 3, everything can be replaced quickly/easily 4, box fan mechanical power switch can work with wifi smart plugs ( on/off trigger by time,schedule and sensor ) 5, bigger fan is relatively quieter for the amount of air it pulls 6, choice of box fan power and cost 7, box fan is moderately easy to maintain ( clean the accumulated stuff off the blades to maintain airflow and lifespan )
Wow! This was packed with loads of illuminating info, even more than your earlier vids. Thanks so much. Keep up the good work.
Comments like this make the hundreds of hours of research worth it! Thank you 😊
I can't tell you how long I've been looking for a video like this. 🙏🤝
I'm happy you liked it :)
Hello! Great video! Did you ever do a CADR test of your DIY solution? It looks like it can be a bit more expensive than CAKs but with the AC infinity fan in there, I have to imagine at a higher speed it has a higher CADR.
Thank you! I haven't done a CADR test of it yet, but The 3D Handyman (youtube channel) said that he may do one for a similar build (same fan and filters). I've been checking his website every week or so but he hasn't posted the results yet.
I agree with your theory that it probably can achieve a higher CADR on the higher speeds.
Homeboys air purifier so strong, his black shirt turned a lighter color mid way through the video.
I appreciate the good work you're doing in informing us folks; great video as well.
I'm grateful for your appreciation :)
A well-researched rant, Alex! You've hit all the marks here.
That means a lot coming from you, David! Thanks for your help with the face velocity stuff.
Thank you, this is exactly what I was looking for. All the fancy HEPA boxes always seemed like a scam to me as all they doing is sucking air through a filter. This has finally given me an option/approach I can relate to. Thank you! Amazing video, subbed and liked 💪💪
Dude that's an INSANE video, the amount of research and effort is honeslty crazy. Customer all around the work should look at this video.
I did drive myself a bit crazy while putting together this video. Thank you for recognizing the value in it 🙂
Very timely. Have been thinking about buying a hepa filtration system. Thanks.
Thanks a lot for this video! Super insightful!
wow! and thank you so much! Can you do one on water filter/purifiers? Having a hard time on which water purifier to buy.
Great suggestion. I'll add that to my list.
We've all been there. Too many experts don't really understand what we are looking for. Good research. I have smart Hepa filters in bedrooms, otherwise three PC fans CR boxes around the living areas. The CADR of the PCCRB is fantastic for low noise compared to a regular box fan CRB. Plus they are smaller. Currently looking for more than 6 air changes per room per hour, I can usually get double that.
I appreciate that, thank you. You nailed your setup. I love shooting for super high CADR hehe. Especially because I unfortunately don't have an exhaust hood over my stove.
Great video, big fan of Clean Air Kits and CR Boxes so thanks for getting the word out!
It's an honor to do it! Thank you so much.
@@HealthyHomeGuide one piece of feedback someone shared with me: some people may take the wrong message that HEPA is a “scam” and shouldn’t be used. I agree MERV based devices are better in most situations, but similar to how Levoit is not technically HEPA and some people are scared by that, some may view this and think HEPAs don’t help, when it’s really, there are cheaper or more effective ways to do this, but there isn’t something inherently wrong with HEPA entirely - agree?
I've had several people reach out to me making this same point that you're making, and I've given this a lot of thought and reflection. Here's what I'll say:
I don't want people thinking that HEPA filters in general are a scam. So I did several things to help prevent this: I included a section towards the end of the video where I talk about the contexts in which the high single-pass efficiency of HEPA filters is needed, I made a pinned comment explaining that further, and I added "Most" to my title after the fact.
I believe it's important to reflect on my messaging, and I have. That being said, I do not regret using the word "scam." Beyond the incredibly deceptive marketing of most HEPA air purifier companies, I DO believe there is something inherently wrong with HEPA in the context of in-room particulate purification.
I believe that HEPA filters are too expensive and restrictive for this particular context, and we need to move away from using them here. In order to produce a good CADR with HEPA, you either need a super powerful fan that is far too loud, or a super expensive, giant filter. Those are not viable solutions. In the real world, air quality usually suffers in the end.
There is a cheaper, more energy efficient, and quieter option than HEPA at equivalent CADR. Let's talk about THAT - even if we may have recommended HEPA air purifiers in the past to our viewers/clients. Sometimes you need strong messaging to get the word out and help create a paradigm shift. So yes, scam.
"Merv filters leave HEPA in the dust". hehe
Heheh 😉
Wow this was a great video. Thank you for sharing your knowledge and research.
I live in Australia so it’s very expensive to import stuff. For example on clean air kits - choosing the tower of power which is $300 USD, the shipping cost estimate is $215 USD. So you pay 2 thirds of the product price to ship it. It sucks but Australia is a long way away from Missouri!
So instead I’m going to watch your diy video and then maybe in a few years there will be a diy version for computer fans. I also don’t think I care how loud it is if it’s performing such an important job. And I can always turn it off when we need quiet.
I’m glad you appreciate the work I put in 🙂
I’m so sorry about that shipping cost. Hopefully the AC infinity fan in my DIY version will ship to you for a decent price. It’s very quiet on the lower speeds. Good luck! I need to find better options for my Aussie viewers.
Great video. Thx for sharing your experiences here.
Glad you appreciated hearing about them!
You can buy particle counters as used in clean rooms. When we had fires a couple of years ago, I used a standard box fan and furnace filter. Used it to clear the smoke from the house. It was very effective. The difference in odor between indoors and outdoors was huge. Avoided the HEPA filters as the goal was to remove large volumes of the smoke particles.
thanks for making this video. i'm in the market for a new air purifier and this information is so appreciated. will share with others as well. keep it up!
Aw, thank you! And thanks for sharing it. I will definitely keep it up.
Yes, the surface area of the filters matters. With Biological Safety Cabinets used in laboratories, the size of the HEPA filters are enormous in comparison to a household air cleaner. The larger the filter given the same fan & speed setting, the more clean air produced because of decreased resistance to flow. Most household HEPA air filters have minuscule filters.
HEPA filters are superior IF the household cleaner is properly designed. Apparently they are not today. HEPA filters can last for many years especially with the usual setup of having a pre filter ahead of the HEPA filter. A pre filter is similar to your MERV rated filter. This is standard in a Biological Safety Cabinet, as described by NSF 49.
thanks a lot! i will build one myself!
Congratulations Alex on another great video - this one is close to my heart having watched the iterations of DIY filters over the past few years and built quite a few myself. I love your energy here and calling out terrible marketing. Great education like this is greatly needed. Thank you! 💪🫡
Your comments are always very encouraging, thank you 🙂
Thanks for the info. I just ordered two of the CleanAirKits 7 Fan end table units, and I’m confident that they will outperform HEPA filter systems that cost over 600.00 each…. So I’m essentially getting 2 awesome air filters for about a 3rd of the price of 2 of the expensive hepa filter systems, with better performance & cheaper filter replacement costs as well. So thankful to have stumbled onto this video. 🙏🙏
Well said! Thank you for taking the time to fully understand what I’m trying to say here.
Thanks a bunch for this video. Switching to thinking about CADR is such a simple and insightful way to understand why HEPA isn't just better.
Before seeing this I just bought a 3rd portable HEPA air filtration unit to reduce allergens for an upcoming visit from my family, but now I can make a more informed choice next time the issue arises.
You have a good soul and smart man, keep the good work bro!
That's one of the best compliments I've received here. I appreciate you!
I have multiple of the clean air kits and absolutely love them. whisper quiet.
Aren't they great? Simple, quiet, and effective.
CADR measurement is confusing on the particle size. Especially when it does say a specific size in a graph since how i understand it, it measure Tabacco Smoke 0.09-1.0 um (some sites say 0.9-1.0um), Dust 0.5-3.0 um, Pollen 5-11um.
I do wonder if Tabacco Smoke particles is filtered like dust mite allergens of similar size. If not than than CADR might be less usefull depending on your specific allergies. Oh and as you mentioned be sure to get the AHAM measurement standard and not the chinese one.
The charts shown at 24:27 are misleading, because the Clean Air Kit chart has a larger scale than the HEPA chart, but is adjusted to look like the HEPA chart. The scale of the first section of the Clean Air Kit chart measures three times larger than the same on the HEPA chart. So, without careful examination, the charts make it look like the Clean Air Kit is cleaning as well as the HEPA, but it isn't. However, the Clean Air Kit chart begins with a higher particulate count.
Thanks for your comment. Clean Air Kits addressed this point in a previous discussion. Here's what they said: "CADR is derived from the rate of exponential drop (sharpness of curve). If plotted on log axes the two decaying exponentials would appear as lines of different slopes where CADR is derived from the slope. The numbers on Y axis are different because the experiments started from ambient outdoor pollution levels on different days. But we get CADR from the relative rate of change or drop, so absolute Y axis comparison is not relevant."
Thanks you so much for the information and now I am going to get my air a bit more cleaner.
Great info, thank you.
I'm glad I stumbled onto your channel. Thanks for the investigation
Happy to do it!
Awesome video Alex - thanks so much for sharing such useful information! It’s great to know that there are low cost IAQ solutions that are even more effective (and quieter) than the much more expensive commercial products we’ve all been led to believe we need. Such a breath of fresh air!
Great comment! That’s an astute encapsulation of the value that this video offers. Good luck Michael!
Just bought an xxl luggable, hope it goes well!
Im curious if you have seen the 'airfanta' purifier: It's just one dude on twitter selling his design in which used a cr box design with 4 large pc fans (overclocked too I think) and 4 heavily pleated hepa filters. According to the site you linked it has the highest CADR to cost ratio.
I bought the CAK anyways bc 1) I like the look of it more and 2)in the US it make sense to go with easily purchased merv filter over proprietary(ish, I think china sells the one he has) filters.
This video was amazing btw!
At full speed it's same loudness as the HEPAs 15 dB louder than ours. And he forgets the m3/hr to cfm conversion inflating CADR 70%. But at lower fan speed should perform similarly to ours.
@@cleanairkits ahh that makes sense, yea the dB's are in 50's and I didn't see the unit conversion. I knew that high of cfm/CADR couldn't be possible and couldn't figure it out but now I know it literally isn't lol.
Hi alex, i have a dilemma that i was hoping for your advice on. My home relies on swamp coolers and AC units. These blow air in from outside super fast, and don't have a filter at all on them. I live in the Mohave desert, so its imperative these run almost always. Can i keep up with cleaning the air in my house when those are blowing in dirty air from outside? Should i put a makeshift filter on the swamp cooler opening? What kind of filters can even resist that kind of damp air all the time, And what options do I have as far as the small rooms, should I build one of those diy filters fans you show and put a makeshift filter on the AC units? Im thinking both right? Ive battled mold in my bedroom, and i also grow mushrooms. I dont know if you know what that consists of but basically for the space they grow in and any mycology work I do has to have air cleaner than 0.3 microns. I am purchasing a laminar flow hood for that, but the cleanest air possible for that space at least us needed. Keeping air in the house clean for health reasons can help maximize my success in that area as well, and help the laminars job a bit easier .I do not have a lot of money so diy may be the best option for me. Can you give me any advice on this? What are your thoughts and opinions if you wouldn't mind? Thank you alex!
Thanks for the questions! Please email me and I’ll be happy to answer you.
I watched over a few days and may have missed it... Care to share your thoughts on the 6 fan brisk Vs the AC infinity build? Both are really nice options.
I heard you name the brisk is going to power on after an outage. In wondering if you think they are similar db for similar cadr. Tough question though because, as you say, it's involved to get the actual cadr from your infinity unit.
Thanks for this and your other videos, really appreciate your work.
Thanks for the kind comments! At 26:24, I give my option on the best option. I recommend Clean Air Kits.
It’s really just an educated guess given that yes, I haven’t personally compared my DIY design with the 6 fan brisk box from clean air kits. I suspect that the clean air kit is superior CADR at similar dB. But you can adjust the speed of the AC infinity and reach CADRs that are likely very high, which you can’t with the clean air kit. But from another perspective, the single speed of clean air kits is an asset.
Anyway, both are great options, I just think the clean air kit is better across the board.
@@HealthyHomeGuide thank you for replying so fully! I love the fun of the adjustable fan if in a variable environment, extra people coming or something. I'm going to try a brisk box 6 out. Adding it to a levoit core 600 and two box fans covered with nanofibre which go in the windows, hoping to breath well through this fire season.
@@oleeotv you’re very welcome! That’s a cool setup. Just to be clear, clean air kits are not speed adjustable. Good luck!
@@HealthyHomeGuide yes for sure, that's one of the things I like about the infinity setup but for day-to-day constant running operation the single speed is great.
@@oleeotv yup, exactly
I’m so grateful for the people that bother calling out BS and letting others know about it! I’m also an avid researcher and SO appreciate the time you spent in putting this video together! We are interested in the clean air kits but we do want the VOC/gases/smell absorption capabilities of carbon filters. I emailed the owner and he said it could be possible to use a carbon sheet filter with the filters they recommend though there would be a little loss in the air flow because of the extra layer of filtration. I could see how the carbon sheet filters would not be as effective as carbon pellets (or even larger carbon filters.) I know the IQAir Health Pro Plus is supposed to be great at this kind of filtration, but I also think I wouldn’t be able to stand the noise level of the highest setting (that is probably where their efficacy numbers are being reported from.) I know you mentioned Smart Air is also quiet but expensive but I’m wondering if that’s the best quiet-ish option for someone that wants effective VOC/gas/odor control?
I’m appreciate that you’re grateful for the work I’m doing 🙂 In case you missed it, I discussed my opinion on carbon filters at 32:09 in this video. To expand on that, I do agree with you that a thin sheet of carbon is unlikely be very effective as an odor reducer for very long (I imagine that it would saturate quite quickly).
In general, I don’t think carbon filtration in in-room residential air purifiers is quite at a place where it can be used as a consistently effective, long-term VOC mitigation strategy. Instead, removing the source of the odor or ventilation (dilution with outdoor air) are proven methods that are far more consistent and effective.
That being said, air purifiers with larger blocks of carbon can have some efficacy. But again, given that companies don’t tend to provide metrics about the efficacy of their carbon filters, it’s hard to know.
@@HealthyHomeGuide I didn’t miss what you said about carbon filters and I agree that the sheets are likely not super effective (or at least would just need to be changed very often). Ventilation with outdoor air is not really a great solution for us (and probably also not for many people) and it’s still an important factor for us. I think IQAir Health Pro Plus is one that does genuinely make a difference in that department but I know I wouldn’t be able to deal with the noise level on a setting where it’s really making a difference. 😝 🤑
@@surrendertoflow78 Gotcha! Can I ask why you feel that ventilation (dilution with outdoor air) isn’t a good option for you? When I say ventilation, I’m not talking about opening a window.
@@HealthyHomeGuide for one, right now we’re dealing with a lot of controlled burns in our area. So outdoor air quality is poor (and most of our summer last summer had air quality that kept us cooped up inside). It wasn’t even this bad last spring so I’m bracing for a hard summer 😷
This is incredible thank you
Thanks for watching :)
You have no idea how much you helped me!!!!!! You are amazing! And yes, I got upset with you too. I have learned a lot. Thank you so much!!!
I love to hear that! I knew this video would upset some people, but I'm glad you ultimately came around.
I can confirm that the DIY box fan solution does a great job at filtering wildfire smoke. It's also been awesome for my allergies.
Ageed that pc fans seem like a good diy option. 6x120mm vs a box fan, the box fan is more likely to be noisy for similar air flow. My garage work box fan is noisy even at a low flow.
I have two hepa filters in my home that has small rooms. I can't/don't want to have big footprint diy merv filter. Does it still make sense to stick with what I am doing when running those units on low 24/7.
First, I’d find out what the CADR of the HEPA units in your home is and whether it makes sense for the size of your space. It’s almost certainly extremely low if they’re small units and you’re running them on low.
If your priority is aesthetics, then stick with what you have. If your priority is clean air, then I’d get something with a higher CADR (assuming I’m correct about the above). By the way, if you watch the whole video, I’m not advocating for DIY units with huge footprints. Check out clean air kits website - they have plenty of units with reasonable footprints like the Luggables. Good luck!
i just bought a hepa filter that claims to do 141 cfm CADR, is that good for the bedroom...
@@benjiebarker That means it delivers 141 CADR cfm on the highest (loudest) speed. So if you’re running it on medium speed, it’ll do around half the CADR (70 cfm). Use the sizing methods I discussed at 27:59 to see if it’s right for your bedroom.
Alex, I really appreciate this video. I’m planning to build a C-R box inspired by your 16 x 30 and SC fan. I’m thinking about using 16 x 25 filters (same area as 20 x 20) and MERV 14 filters. Please comment re. MERV13 v. MERV14 for this application. Thanks!
Many thanks Robert! 16x25 is a great size. Both MERV-13 and MERV-14 are good options, but MERV-13 may hit more of a sweet spot which balances airflow and efficiency. See the article entitled “What happens to CADR with different grade filters?” on Clean Air Kits site.
Just buy filtrette or other high quality filters
Lennox actually has as 20x20x5 (and other sizes) MERV 16 filter that cost $100. So far it's lasted a long time for me. I don't use it as a room filter but my HVAC is able to fit this thickness just barely and the pressure drop is incredibly low in my testing, and in their airflow charts for initial resistance. So far after about 8 months running 24/7 i haven't seen any real deviation in measured static pressure to indicate it's clogged yet, at 650cfm I'm seeing at most 0.01" wc increase from when it was first installed.
If someone wanted to drop $200 for 2 and make a triangle room filter it would probably be pretty good. However after seeing the chart you showed of Merv performance in ultrafine, 12 and 14 actually have still pretty good performance in the middle range and very similar ultrafine performance to merv 16. I'd say it's a really good almost HEPA filter for significantly less airflow resistance, for a home Merv 16 is functionally the same as HEPA.
This is a really well-informed and well-written comment, thank you! Are you talking about the Lennox Healthy Climate filters? Those are absolutely incredible. I actually have a video where I build a simple fresh air intake system around a Lennox Healthy Climate filter. It’d be super cool to test those in an in-room air purification context.
@@HealthyHomeGuide Yep that's the filter I'm talking about. I'll have to check out that video
Hello thank you for the video. I got a little nervous that I've wasted money on the HEPA filters. I have winix zero pro that has 470 m3/h on highest setting. I usually let them run on highest or high in general. Should I reconsider into another brand since I'm from Europe and I can't buy the brand you recommended. I usually appreciate how really fresh the air is with HEPA 13 filtration though. I haven't gotten the same feeling from the Marv. I would really appreciate your feedback. Thank you for taking the time to read
I can't post links in comments, but clean air stars, the website I talked about that I linked in the description, has an air purifier selection tool that allows you to search by country.
@@HealthyHomeGuide I appreciate your reply. I've already checked it and for Bulgaria they are not supporting basically. Can you name any other brand that has a similar mission to theirs? If u can't its cool. Thanks a lot cheers
That's funny, years ago I used a filter in place of the side panel of my negative air pressure pc case. It was an inelegant masking tape mess from being a kid so eventually I gave up on it.
Nice! You were ahead of the curve.
you sir, are built different. bravo
Hahah I love that. Thank you.
Great video! Looks like my earlier comment disappeared; maybe not posted where I included an Amazon link? Apologies. Anyways, I was wondering if you had any data on efficacy of a single filter DIY purifier (ie Lasko box fan + MERV 13 filter). We're doing this as a space-saving measure in smaller living quarters, but was curious how effective it is compared to commercial options. TIA.
Can be pretty good if you use a 4" thick MERV13 but otherwise about 1/3 the CADR of the 4-filter cubes.
@@cleanairkits Ah, good to know, thanks for sharing!
A Lennox Healthy Climate filter could potentially be amazing in a single filter application. They're 6" thick, MERV-16, and have an activated carbon layer for VOCs, and I've heard their pressure drop is relatively low.
I had an electrostatic precipitator when I was growing up due to several allergies. I haven't seen anyone talking about those.
Interesting question. Electrostatic precipitators can be effective, but they are also known to produce ozone, which can be harmful. Search "24387032" in google if you're interested in seeing the study that confirms this.
You're looking good! There have been several videos where I was concerned for you, because, as was said in my Texas home town, "Looks like he was rode hard and put up wet." You look robustly healthy, now (an excellent endorsement for your safe home information). I also went to Clean Air Kit and asked about integrating their system into a new house build. I am building an historically-inspired Spanish Colonial Revival house in Arizona. I am not interested in using up any of my precious floor space with individual room filters; I contacted Clean Air Kits to ask for their help to integrate their designs into a continuous low-velocity whole-house ventilation system. I'll keep you posted about how that works out. Keep up the good work!
Thank you. This is tough for me to admit, but it’s taken some courage for me to release videos knowing that people may think I look unhealthy. But I’m glad you see the improvement and that it serves as an endorsement of my methods!
That’s an interesting question! I’m curious to see what the guys at Clean Air Kits have to say in response.
@@HealthyHomeGuide They recommended a balanced ventilation system (fans extracting as much air as the whole house ventilation fan brings in) all filtered with MERV13 filters; which is easy to do. They are really focussed on the retrofit market, not new construction, and do not recommend adapting one of their systems. I am going to steal one of their good ideas, though, and use black metal mesh to disguise the bright white filters when the filters are visible through vent grates. I'm researching Braun and April Air ERV systems (Zehnder is great - but German engineering costs beaucoup bucks).
Do the fans have any coil whine?
I am anxious to see how your larger single EC fan compares to six 120mm server fans in sound db and energy use at CAGR above 300 cfm. I suspect that it might be close, with the larger single fan having a higher maximum flow.
The PC fans should have a decent advantage in efficiency. The large fan is a standard shaded pole single phase AC motor, typically they run around 25-30% efficiency. Box fans are bottom barrel quality for static pressure and sound, the round AC infinity fan he's using is much more optimized for static pressure and sound and a good choice for filter boxes aside from maybe a squirrel cage style blower.
The PC fans these days are all brushless DC motors, a misnomer of a name but regardless these are typically 85-90% efficient. There will be some losses with the AC to DC conversion and the PWM driver, so let's say total efficiency is 60%, 10-15% for the AC to DC conversion and 5-10% for the PWM driver. Significantly more efficient than a shaded pole motor. They optimize the blades heavily for specific applications of either static pressure, airflow, or balanced. AC infinity was good but PC fans are highly optimized with a lot of R&D money spent constantly to improve.
PC fans are garbage in terms of static pressure though.
I'm glad I'm not as environmentally sensitive as you, but I still care about what I and my family breathe. Thanks for this eye opening video and I wish you a good luck on your mission.
That's very kind. Fortunately, over the past several months, I've healed considerably and am less environmentally sensitive. I hope that trend continues. Thanks for your support!
Using a MERV-13 filter in your home central heat and air conditioning air handler may seem like a great idea, but don't. The job of the filter in your central air handler is only to keep your air conditioner coils clean. That filter is there for that purpose and that purpose alone. Any filter higher than MERV-4 will restrict the air making it harder for your air handler to efficiently distribute the heated or cooled air throughout your home. It can actually cause your indoor air conditioner coil to freeze up into a solid block of ice in the summer, and you know how bad it sucks to not have air conditioning during a heat wave.
Just make DIY air filters with MERV-13 filters and put them around your home especially where you spend the most time like the bedroom and living room. You'll get superior air filtering that way. The cleaned air will even put less work on the air filter in your furnace and get circulated around the house that way, too. My DIY filter actually keeps my window air conditioner filter cleaner for longer.
Im a mechanical engineer. The vendors in HVAC have been trying to convince you of the “medical benefits” of HVAC widegets for at least the 45 years I’ve been in the field. Lmao
Thanks
yup - a $20 fan and a 6 pack of Merv 13s for about $40 - you'll be good for a year in a 1000 sqft living space. I actually got 3 fans; bedroom (white noise), living room and my home office where I'm allowed to smoke... on occasion.
Thank you for this video, I have been so confused trying to figure out exactly what I am buying.
Your home made filter only needs one or two simple modifications to fan blades and to change the filters in rotation of time per filter to exceed anything you could buy for home use.
Totally agree.
Thank you!
You’re very welcome!
Welp, watched this too late after buying a used Coway and a new filter for it. I'm not a fan of how the clean air kits look but I value safety more than aesthetics. Guess I'll be saving up for a clean air kit. I appreciate your video.
I salute you for valuing safety over aesthetics. Maybe someday we'll have very aesthetically pleasing AND effective air purifiers.
was one of your heapa ones, brand from Levoit , this the heapa I use. just wanna know if I need better.
also you seem to have alot of knowlage, I have 2 questions.
I need one for air inside, after I have vented out the majority of air, via hose, but some will flow out into room when opens.
my use case is 3D print and airbrush painting.
Aerosols and volatile organic compounds are produced when using resin 3D printers (in the range of 41 to 45 nm and 161 to 322 mg/g printed respectively)
what filter on cr box would I need._??
Levoit air purifiers definitely work, but are noisier and less energy efficient than PC fans + MERV-13. It's your call.
@@HealthyHomeGuide thank you.
yea I just got worried that it was kinda not.
Anyone know of any decent merv13 filters in Australia?
PM 2.5 how filters how effective is it in removing dust particles, since it is only rated for 2.5micron to 1micron, my room dust particles are mainly fine black soot from cars, what is the size of these pollutants?
As the data shows, CR box type designs with MERV-13 filters maintain their performance across the entire range of particle sizes, from ultrafine to larger.
i recently bought a Winix 5500-2 Air Purifier, lots of positive reviews, best cost/effective. etc. it does work, but there is a problem with it, the hepa filter releases a horrible chemical smell making it unusable.
Merv13 has a much lower efficiency of filtration compared to HEPA. I wouldn't recommend these DIy units for severe allergy sufferers. The reason for the high CADR is because they have less resistance as the pore size is larger allowing the smallest particles and the most damaging particles to pass through.
Filtration efficiency is not a direct measurement of how well the air in a room is cleaned. CADR is.
CADR is measured by assessing how quickly particles are removed from the air in a room. The research that I discussed in this video uses particles of many sizes, from ultrafine to larger (which includes allergens).
In general, MERV-13 DIY units have been shown to clean the air more effectively than HEPA units regardless of particle size. Even though HEPA filters are more efficient. In this video, I explain why.
I think the data I presented in this video supports the idea that HEPA units are often actually an inferior choice for allergy sufferers.
Subbed
Furnace filter rec if also using Your Homebuilt or Clean Air Kits?
Vacuum cleaner rec if also using Your Homebuilt or Clean Air Kits?
Thank you
Cheers
Filters: 3M filtrete MERV-13 (MPR 2200). Vacuum: I use Miele’s Complete C3 Calima PowerLine (SGFE0).
Hi Alex, love your video but unfortunately im not big DIY guy and also it's important to me how device looks...So im looking to buy humidifier from Stadler with 2 HEPA filters in it to mostly raise humidity levels of my studio apartment and maybe also remove some dust etc. But after watching your video I start to have doubts. So will I better be without anything or with this overpriced designer humidifier, what do you think? I have no allergy, but my place is super dusty and has low humidity ~30% on average. I had one of smaller ones in the past and it worked okay (in terms or raising humidity levels, don't know what about particles filtration).
Hi! I think you'd benefit from watching my video "How Healthy is Humidifying REALLY?" It's a great intro to how to do humidification safely. If you have more questions, feel free to email me and if you're interested, you can book an air quality consultation. Thanks!
Ok, what if...(and I'm just spitballing here) I put 4 hepa filters AND layered 4 Merv in some way, and then put a fan on top? 😁
I kinda see it as paying for esthetics. Regarding maintenance cost.. I'll replace the $100 filter every other year (even if their change-filter indicator goes off sooner).
What would you get, if you had to get any of the following:
Medify MA-112
Nuwave oxypure
Shark purifiers HP302 or HC502
Winix 5500-2
Kenmore PM1005
LEVOIT Core 300 , Core 600S
is that a genano in your background that keeps appearing and disappearing? running the hvac with a MERV filter on fan only will do a great job as a whole house filter... those fans shouldn't be put too close to the body due to their magnetic fields which some say can cause healthy problems... they should be kept about 8 feet away from living mammals based on my measurements on the magnetic fields from a few fans and purifier fans...
CR Box - have you come across a washable MERV13 setup? I recently saw a video where someone combined a screen with *paper towel* as an ultry-cheap DIY filter. And that's interesting. Replacing 4 single use filters frequently will get expensive fast. If I can, I would like to get either something with cheaper maintenance cost or that are washable. (For wildfire season).
Good question. I do not recommend reusable filters. You have to clean them. Doing so can expose you to the harmful stuff you've collected on the filter, in addition the new harmful stuff that developed on the filter.
@@HealthyHomeGuide Hmm. I could see that, especially if they're not properly cleaned.
I saw a MERV 8 one that's a slip-cover (like a pillowcase) over a metal frame, that you remove and then wash in your washer. That seemed pretty safe and easy to clean properly, but it was only MERV 8.
I also saw some all metal ones that are supposed to work off electrostatic principles, that you wash outside with a hose or vacuum out frequently, but again, MERV 8.
I can see how some of the other ones I saw could be harder to clean properly, but seeing these types gave me some hope for a less expensive alternative.
The idea I was pondering that looked like it *might* have potential, was combining the disposable paper-towel-filter idea (or the MERV 8 slip cover), with the MERV 8 aluminum electrostatic filter, which should be safe to clean. But I haven't seen the paper thing tested, and I don't know exactly how layering filters affects their MERV rating, if at all.
I live in the mountains in BC, and don't make a ton of money, and wildfire season, I worry might chew through filters faster than I could afford to replace them, leaving us stuck with no filters at all.
I was hoping you might have heard of some versions that worked well. Maybe this season we will take our chances and hope the disposable filters last, and if they don't, suffer through the rest of wildfire season without filters if we can't aford the replacements, then next year save up for the metal ones and experiment with different filter mediums to try to catch the smaller particulate.
Anyways, thank you for the information. I appreciate your channel, and hope your mold illness is improving.
I’m glad you brought this up, these are good questions about an important scenario. Replacing filters can definitely get expensive during wildfire season in places with frequent wildfires.
Cleaning washable filters thoroughly enough is definitely something to keep in mind, but my worry with washable filters is that the process of washing them properly invariably causes whatever harmful matter they trapped to be released into the air again, especially when water first contacts the dry filter surface. Hosing them off outside is safer, but makes it more difficult to clean them properly.
Used filters shed a surprising amount of particulate when they’re being handled. Handling 4 larger filters (as in a CR box) and washing them regularly (properly) would definitely be a tough situation to avoid a significant amount of exposure, in my opinion.
As far as the paper towel filter idea, I’d estimate that such a design would be around MERV 2, or MERV 4. Something very low. (Though I don’t think the MERV system even applies to filters like that).
It’s unfortunate that there aren’t better options for people in your situation. I’ll be on the lookout for solutions that could help you.
@@HealthyHomeGuide I will try disposable filters this year, and if they don't hold up I will have to experiment with stacking these two least-bad washable Merv 8 options, and see if I can add anything inexpensive to it from there.
Do you know if there's a formula or something that shows how much added protection you get from stacking filters? Like, if you have the air go through two MERV 8 filters, that's bound to catch more particulate than one, right? But how much more?
Anyways. I will keep an eye on your channel for relevant videos, and if I have to experiment I will get in touch. There must be a way to test such performance in advance to know what the MERV rating of a custom filter is.
With a shnozz like yours I'm sold on your take for air purifiers!! Thanks for the insight!
The schnoz knows.
Bruh
great info
Glad you think so!
You the best keep it up
Thank you, will do!
I have 6 different air purifiers and the best one I have felt to be around is the Austin Air. But I've also made one out of a huge dust collector filter that has over 300 sqft of MERV 15 media that I added an 8 inch vortex duct fan to it. It's very effective.
I used to have a few Austin Air HealthMates as well. I feel the air is cleaner when I’m running a Clean Air Kit. Austin Air also doesn’t share CADR.
The Austin Air HM400 is very low CADR. I've tested them. About 155 CFM CADR on high (unusably loud) and 77 on medium (tolerable) and 35 on low (quiet but very low CADR). They do have a large carbon mass though.
For someone who owns pets and their main concern may be air odor would be a main concern would a box kit be better in that case or a hepa?? 🤔🤔🤔
The most reliable and effective way to reduce indoor odors (besides physically removing the sources of the odors, which isn’t always possible) is to bring outdoor air inside. This is also called dilution. Best way to do this is with an energy recovery ventilator (ERV).
@@HealthyHomeGuide very interesting. I’ll look into that ! 👌
I got enlightened by your video, but I'm wondering if this ship has already sailed?! The famous Coway 1512HH will cost me $159 in US Amazon, arrives plug and play, and each additional HEPA filter costs $20. Well, the cheapest CleanAir kit seems to cost twice the price ($300!), needs some sort of diy final assembly, and the 3M MERV13 filter costs $26 a piece. (They need two, but I guess they last twice). So in terms of overall upfront investment and readiness to start filtering in my new house, I'll go with the cheapest, plug and play solution even though it is less energy efficient, louder than a jet engine and takes 3 hour longer to clean a 2-week worth of accumulated cat hair in my bedroom. It might make sense if I 3D print the entire thing myself and self-source fans from China, but then this would cost me a dearly amount of time + it won't be accessible for the general, non-nerd public.
Thanks for the question! If you’re outside of the US, clean air kits shipping will be expensive unfortunately. If you’re inside the US, their cheapest unit is $99. Assembly with the MERV filters is quite easy and should take less than 20 mins (it took me 5 mins).
Additional context for the Coway 1512HH: its replacement filter kit costs $60. If you’re getting them for $20, they’re very likely to be poor quality. Also, that filter surface area is relatively low, so if you run it on super loud turbo mode, it’s very likely to get clogged up with dust far sooner than 6 months. That 6 month filter change recommendation they give is not based on running on turbo mode, it’s typically based on low-medium mode.
So basically, HEPA is already restrictive, when you have a small filter size, as here, it becomes too restrictive quite quickly. CADR invariably suffers.
Not sure where you live, but there are other options for those in Canada like North Box systems. Also, my own DIY air purifier works well. But of course, I respect whatever one you feel you have to go with.
Also, an air purifier with a worse CADR won’t necessarily clean 2 weeks of cat hair in the way you imply. Most of that ends up on the floor and gets kicked up it your breathing zone when you walk. So that dander is essentially being continuously re-generated in your space. A unit with a better CADR can clean it faster so you breathe less of it on average. But still, any air purifier, no matter how good, is at least somewhat limited if your floor isn’t clean.
Are these diy/ clean air kits air purifiers good for pet hair? I have a dog, and I'm constantly sweeping dog hair and dust.
Good question! Air purifiers in general aren’t great with pet hair. This is because pet hair tends to fall to the floor quickly; most of it doesn’t stay airborne for long enough to get captured by an air purifier. Some smaller hairs do get captured though.
However, pet DANDER is a different story. Air purifiers can be decent at capturing pet dander because pet dander tends to stay airborne for longer. Clean air kits air purifiers should do this very well, yes. You’ll still have to clean though.
@@HealthyHomeGuide thanks for the info 👍
You’re welcome!
Thanks for the video. I would really prefer that you name the company of the air purifier that didnt work for you. Not for shaming, but for repeatability
What about the LG puricare ?
All HEPA filters are a scam unless they say they 97.999% to be rated HEPA (high efficiency particulate air) it has to be rated at 97.999 at 0.3microns. Not only that for the filter to be efficient you have to exchange all the available room air in a given amount of time. Most air purifiers could not filter the air in a closet, no less a room !
bad things about the HEPA purifier units for rooms - 1, model specific replacement filters are expensive and can be hard to find for most models 2, a medium size HEPA purifier filter is about half the size of a 1 inch thick 20x20 inch furnace filter ( that DIY box has 6x more filtering media !) 3, HEPA filter will clog up much quicker ( less air throughput over a period )
Would running an AC on fan clean air too?
Yes, if you’re referring to ducted central AC, and if MERV-13 or higher filters are used. But in-room air purifiers can further improve indoor air quality even for those with central AC.
Currently making a review video for Dreo's new 2 in 1 air purifier tower fan... wew this videos gonna make things tough
Hahah I’m sorry 😅
Wow Adrien Brody makes videos about air filters😯
I like HEPA for the exhaust side of a vacuum. They make sense for the small volume of air that needs to be cleaned before returning it to the room being cleaned. I hate the smell of dust being returned into the air behind a vacuum.
Other than a Silicon Valley clean room, or an operating room at the hospital, which probably use multiple large banks of HEPA fan/filter, they don’t make financial sense.
Couldn't have put it better myself. I agree 100%.
After about 3 years of experimentation, I'm using a Xiaomi H13 True HEPA filter with a 3D printed centrifugal blower. The motor is around 40W, and the diameter of the centrifugal fan is 32cm with a height of 10cm. For air monitoring, I use a PMS7003 laser particle sensor capable of separately measuring PM 1.0, 2.5, and 10 values, along with a BME680 VOC sensor integrated. The filter, in a house of about 160m², brings the PM 1.0-10 values down to zero within approximately half an hour, producing crystal-clear air silently, with strong airflow even at a distance of 5-8 meters. The filter needs replacement about every six months because it starts emitting a strange odor.
The real issue lies with VOCs. There is very little and ineffective activated carbon in the filter. I supplemented it with 5kg of activated carbon, but it didn't yield results because it can't filter out everything, and the smell of carbon actually raises VOC levels.
In my view, the biggest problem in winter is the high VOC and other chemical pollution. Currently, I don't know how to deal with it effectively because ventilation is not a solution due to outdoor pollution from traffic and other sources like wood burning for heating, which neither HEPA nor activated carbon can filter out.
Fascinating, thank you for explaining. If you can get them where you live, the Lennox Healthy Climate filters are absolutely incredible. I've also lived in a place with poor outdoor air quality from wood burning and I used them. They have a decent carbon layer and are MERV-16. I did testing on them and they're very efficient. They obviously won't capture everything if your outdoor air quality is really bad but I think it's worth it to get that fresh air and dilute those indoor VOCs. One option for you to ventilate in winter would be using a filter box to put one of those filters before an ERV. Email me if you want to book a consultation about it.
Merv 13 16x20 x1 filters are 37 bucks a piece here.
Are air purifiers ok to buy? Which one do u recommend?
I discuss that in detail at 25:44.
Govee is only$30 on Amazon and it works beyond great
@@dmo848 thanks 🙏🏼
Silly question 🙋♂️
Did I just waste money buying the IQ AIR ?
Great video but you can get some pretty substantial purifiers quite cheap in comparison to DIY or even the guys you mentioned. You have to consider the hours of work that goes into making one. Time is money. You can buy a 3000i Philips today for £269 in UK. Even if you ran it at half speed, it will still do a pretty good job and be quiet. If your whole house is open plan then this can be a problem but the whole idea of purifiers being an essential item is a bit of nonsense. If people live to a ripe old age in China where the air you're breathing really is going to kill you, then it's not much of a problem in most Western countries. If you spend a lot of time inside, you're far worse off. Also, the filters and fans and regular replacement will cost more than you think and that's without the labour added on.
"ASHRAE is recommending that MERV 13 filters be used where possible, with MERV-A 13-A or MERV 14 preferred."
There are numerous different contexts and settings in which filters are used. The optimal type of filter varies between them. MERV-13 is sufficient (or even optimal) in many of these.
However, HEPA is necessary in some: for example, vacuums, powered air purifying respirators (PAPR), clean rooms, operating theaters, or nuclear laboratory exhaust.
Also note that ASHRAE gives the minimum standards.
@@HealthyHomeGuide I just found this while watching your video and thought it supported everything you were saying.
Already had a general idea that HEPA was overkill for home use and had settled on MERV14 being the sweet spot for HVAC based on the tables of single pass removal rates I saw. (I intentionally installed a 20x25x5 filter in mine for lower pressure drop)
However your video showed 13 and even 12's doing better than those tables, that and the ASHRE recommendation suggest 13 might be the better choice to balance efficiency and noise while still being effective on 3 ACH for the whole house.
@Sythemn Absolutely, that makes sense! Also, good thinking using a large HVAC filter to lower pressure drop.
I’d just like to reiterate for anyone else who reads this comment that this video is specifically about in-room air purifiers, not other contexts that require near 100% single-pass efficiency.
Hi im dealing with suspected asbestos inside the house, what merv do u recommend merv 13 or 14 or 16? Also if i use merv 13, whats my assurance that the particles that get trap doesnt g
Escape as I continually use the box fan with merv 13? I double the filter one on top of the other. I didnt do the 4 filter squire. @@HealthyHomeGuide
The Air Purification Education channel put out a video a year ago calling the CADR rating "garbage". I'd like to know your thoughts on the arguments that he presents in that video. I will say, I am far more convinced by your video.
I'll try to summarize but don't want to oversimplify his position.
-CADR only test the units for the first 20 minutes of operation with claims that the CADR rating would decrease rapidly overtime. Sometimes within an hour.
-CADR does not test for ultrafine particles
-CADR test chamber does not represent a typical real world environment (as is the case with many testing procedures IMO)
-Many of the BEST air purifiers don't have a CADR rating (not like companies would shy away from a universal standard to compare performance?)
Thank you for bringing these arguments up. I’ve also seen these arguments on the websites of a few popular HEPA air purifier brands. Not exactly the most unbiased source for an anti-CADR message, as I’m sure you’d agree.
Given that I want to take the time to carefully respond to each argument, I think I’d like to do so in a video. Stay tuned, and thanks again.
@@HealthyHomeGuideThank you for the quick response. I look forward to the next video.
These are kinda red herrings, drawing attention to relatively small +-10% imperfections in the CADR metric while missing what we consider the elephant in the room: most HEPAs are being operated at their medium speed for ~50% less CADR, or even low or sleep mode speeds for 70-90% less than their advertised CADR at top speed.
Yes, CADR performance will drop over time as the filters load with DUST, but Corsi-Rosenthal boxes have so much MERV13 filter area (often double or triple your single home furnace filter). This spreads out and slows the loading. People like Dr. Corsi and Sri who've remeasured their CR Boxes that ran for a year have found only 10-15% CADR drops.
We did a real-world experiment in a 600 sq ft apartment and the drawdown rate reasonably matched the predictions from official CADR for both the HEPA and MERV13 purifiers: www.cleanairkits.com/blogs/news/can-the-luggable-xxl-mix-large-rooms-better-than-a-large-hepa Because the "real-world" space was not perfectly sealed, the drawdown plateaued above zero, but the initial sharp rate of drop still follows the 60*CADR/(room volume) -> ACH time constant.
The evidence we've seen suggests the worst pollution impacts on health from the PM2.5 (2.5um) size range, and most viral aerosols are in the AHAM DUST size range (0.5-3.0um). So when manufacturers try to differentiate by claiming to excel at capturing ultrafine particles, ask them for the evidence that these are an exceptional problem? What will have a bigger practical impact -- removing ultrafine particles or accelerating removal of PM2.5 and viral aerosols?
CADR is not a perfect measurement -- but it's a reasonable method focusing on the most relevant metric -- the rate of removal for particles within a particular size distribution. The messy part is the drawdown rate does vary some with the size of particles encountered and how well a particular type of filter captures those sizes. The AHAM AC-1 procedure therefore repeats the measurement with 3 particle size distributions: tobacco smoke (0.09-1um), road dust (0.5-3.0um), and pollen (0.5-11um): ahamverifide.org/wp-content/uploads/2020/06/Air-Cleaner-Performance-FAQs.pdf As explained in the video, most filter media has most difficulty capturing particles around ~0.3um, with better performance on particles tinier and larger than that. Samplings of the distribution of sizes in wet aerosols expelled by contagious humans in laboratory experiments are most concentrated in the DUST range (0.5-3.0um) despite dry isolated virii being smaller (0.1um).
@@cleanairkitsThank you for the well informed response.
What I actually found to be interesting in the other videos comment section is when the question was raised, well if we shouldn't be using CADR, then what metric should we be using to make informed purchases. The response was to refer to EN1822 certifications or other 3rd party lab certifications. A quick amazon search only turned up one result for EN1822, so I'm not sure how as consumers we are supposed to use that as a guide for selecting our devices.
Also to build on your final point. It appears that the Merv 12-14 rated filters can capture ultra fine particles demonstrated by the graphs shown @17.05. So not only are these filters capturing the AHAM DUST size range, but the ultra fine range as well.
Sadly it seems companies are rarely keen to share metrics that can be directly compared with their competitors. Bottom lines rather than honesty with consumers.
Say hello to your kitku! ❤
Do you think Air purifiers with UV light/ozone helpful?
In general, no. I think extra features like that are to be avoided and introduce chemistry into our air that we don’t understand well enough to be using, or in the case of ozone, have already been shown to be harmful to lung tissue. The article I referred to at 32:09 (and linked in the description) also discusses those features you mentioned.