What is the best DIY Air Filter?

Let's test every DIY and Pro Shop air filter out there. What's the best? We will find out! We test standard box fan air filters, several Corsi-Rosenthal Designs, the standard pro models, and my two designs (plans below).
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www.etsy.com/s...
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====== SHOPPING LIST ======
(buying from these helps the channel)
FANS
Lasko 20in Box Fan (best price):
amzn.to/3c3nVNF
Air King 20in Box Fan (best performance):
amzn.to/3Tbzl1O
Caterpillar FAN: amzn.to/3TD9NM3
Maxx Air Fan: amzn.to/3fXokQC
Pro Air Filters
AirDoctor: amzn.to/3zd27Zd
Shop Fox: amzn.to/3aLEKwk
Jet 1000: amzn.to/3PUJ7nZ
MERV 14 FILTERs
Nordic Pure 20x20x1 (12 PACK):
amzn.to/3O6GGgr
Nordic Pure 20x20x1 (6 PACK):
amzn.to/3o5Ge7E
Nordic Pure 20x20x4 (1 PACK):
amzn.to/3AYyiwC
3M Filtrete 20x20x1(2 pack)
amzn.to/3duBAxY
MERV 13 FILTERS
3M Filtrete 20x20x1(4 pack)
amzn.to/3hUCPbV
MERV 12 FILTERS
Nordic Pure 20x20x1 (6 Pack):
amzn.to/3O6HaTN
Nordic Pure 20x20x4 (1 PACK):
amzn.to/3crRhpm
MERV 8 FILTERS
Nordic Pure 20x20x1 (6 Pack):
amzn.to/3Rz9T6G
Nordic Pure 20x20x4 (1 PACK):
amzn.to/3IPFSM1
GAFFER TAPE
Better than duct tape for this use
amzn.to/3AR6E4Q
DIGITAL ANEMOMETER
For testing wind speed
amzn.to/3OkzmhF
====== LINKS ======
Airflow was calculated here:
www.cuidevices...
Article on PRO Filter Performance
www.woodmagazi...
Corsi-Rosenthal Article:
www.texairfilt...
3D PRINTED PARTS (Build at your own risk)
Air Filter Clips:
www.thingivers...
Drum Fan Edge Clamps:
www.thingivers...
BUY 3D PRINTS (if you don't have a printer)
Air Filter Clips:
www.etsy.com/l...
Drum Fan Edge Clamps:
www.etsy.com/l...
BUILDING PLANS for 8 Filter Design (BUILD AT YOUR OWN RISK)
the3dhandyman....
The 3D Handyman is a production of 2 Point Media. Stay classy!

[@godbacchus]

I live in Mexico and rather than using an AC, I have a number of fans which circulate air into and out of the house... dust is always a problem. I don't know why I never thought of attaching a filter, but this information is very helpful.

[@The3DHandyman]

The filter option is great when the air temperature outside is too hot or too cold or it is polluted from cars, industrial facilities or pollen. Otherwise, I do prefer the fresh air!

[@iggiewalsh2237]

@@The3DHandyman most developers in the USA don't factor road pollution and it leads to asthma or cancer!!

[@The3DHandyman]

@@iggiewalsh2237 So true. I think about this whenever I drive by a new apartment complex next to a highway.

[@H0mework]

You might want to consider a swamp cooler if it’s dry.

[@royce9018]

@@iggiewalsh2237 lol

[@Lone.Willow]

@The3DHandyman, there's an old saying: "The best dust mask is the one you're willing to wear", and I think the principle applies here, too. The best air filtration is the one you're willing to turn on, and a big part of that is how noisy the filtration is. It would be easy to achieve greater airflow by simply using bigger and bigger fans, perhaps even stepping up to 240V or Three-phase power in a shop setting. The thing is, if you need two layers of hearing protection to use your air filter... you're never going to use it. I'd LOVE it if you could start to factor noise levels into your testing as well. It might shake things up, and show that if you want top performance, option A is the best, but if you're wanting good performance and low noise, Option B is the best. Thank you for your great testing work so far!

[@liannebenn2097]

I don't think 240 volts means something works harder than 110?

[@drjasonharrison]

240v at 30 amps is a clothing dryer or electric oven. 120v at 15 amps is your microwave oven or clothes washing machine.

[@igatmatthew2283]

I like the way you presented the information. Makes me believe that KZbin still has genuine content creators and not clickbait artists. Definitely gonna try some of the setups you had in the video

[@The3DHandyman]

Thanks very much! It has definitely been a grind trying to do things the right way but it appears to be getting some traction finally. I appreciate the comment!

[@burtreynolds3143]

I agree. Nice presentation. Looks like you bought the filters in bulk. Where did you find the cheapest option ? WalMart ? Amazon ? Other ?

[@The3DHandyman]

@@burtreynolds3143 Thanks again! Amazon tends to be the cheapest option for most filters because shipping is free. For 3M filters, Lowes actually has pretty competitive prices when you buy in bulk. If you buy from Amazon, I'll get a small kickback which helps the channel quite a bit.

[@clinthanson7712]

I want to thank you for these videos on air filtration for a workspace. I am about to open a community Art/Maker Space for veterans/first responders and their families. Creating art or simple projects with others helps combat PTSD. So the quality of the air in this space is very important to me. You have helped me make sound choices on how to create a safer environment for everyone. BIG THANK YOU.

[@The3DHandyman]

Happy that I could help, Clint! These wont do much of anything for VOCs. Be sure to vent paints, solvents, etc.

[@clinthanson7712]

@@The3DHandyman Thanks that is great advice.

[@mDeltaKilo]

Where will you be opening your space (for the minuscule chance it may be accessible to me)?

[@clinthanson7712]

@@mDeltaKilo I am located just outside Kansas City MO area.

[@ingrownnipple]

@@clinthanson7712 really interested in this concept. I'm not local to you but would love to hear how you're planning on running this and funding it.

[@blakes8901]

this is going to sound disingenuous, but I am so proud of you. this video is absolutely amazing and so unbelievably thorough for someone with a channel that "only" has 20k subscribers. I am begging you, please, keep going. you have the veracity and perfectionism to become a serious force for good for the layman and professional alike

[@The3DHandyman]

You are awesome. More content is on the way (for this subject and others)!

[@deusvult7947]

This is fantastic, totally blew my mind. The way you filter all that data down to a usable information is quite impressive, hopefully this video will continue to be in circulation for years for those who choose to build their own diy filters.

[@The3DHandyman]

Thank you! I hope so too. I will be testing even more DIY options with this process very soon.

[@TomLopez17]

@@The3DHandyman I am currently looking into air filtration for my beginner garage woodshop. In looking around for different systems I found that many did not perform to the standard in which they are sold. Online reviews show many air filtration systems that perform at XXX CFS will in actuality be much less once in use. I have decided to make my own air filtration device. This led me to the 'This Old House' air filter and then the DIY rabbit hole and then to your video here. The way you break down the information and show the outputs is VERY helpful. I think I will put my current project on hold in order to build the design you came up with. I need to look through the rest of your channel and see if I can find a build guide for your air filter design. If not I will come up with one on my own. Thank you for taking the time to make the video as well as you did. I will definitely be watching more of your channel. (I already subbed and all that)

[@andysontag5336]

I’m really impressed with your videos. It won’t be long until you have as big of a following as some of the other larger channels. If you've seen Project Farm's video on furnace filters, he shows that one 1” filter greatly outperforms other 1” filters. Turns out the 3M Filtrete 1900 (Merv 13) had more air flow compared to other Merv 13 filters. The reason it performs so well is because it has a lot more pleats which allows more filter media to be crammed in. His measurements showed around twice as much surface area compared to other Merv 13 1” filters. So in theory, if a 20” x 20” x 1” filter has twice as much filter surface area due to having more pleats, it would be the same as using two 20” x 20” x 1” filters with half the amount of filter surface area (fewer pleats). I think what you put together works great and has a lot of value, although I think it would perform even better if you substituted a better performing filter which appears to be the Merv 13 and 14 Filtrete filters. In my eyes the 1900 (Merv 13) hits the performance vs cost sweet spot, especially if you pick them up at Lowes with a quantity discount. However, you can find the 2800 (Merv 14) filters on Amazon, but they cost ~50% more. Another way to improve performance without increasing cost is to use a physically larger filter. So instead of using 5 20” x 20” x 1” filters for a Corsi Rosenthal box, you could use four 20” x 30” x 1” filters. Four 20” x 30” x 1” filters should perform the same as six 20” x 20” x 1” filters, or 7.5 16" x 20" x 1" filters, and cost less. Looking forward to seeing your future videos. If you happen to stay on the filter subject, I’d love to see some performance numbers of a Corsi Rosenthal box using Filtrete 1900 and/or 2800 filters. It would also be interesting to see if they improve the performance of your eight filter box using 16” x 20” x 1” filters.

[@The3DHandyman]

Thanks for the great comment! I have seen a lot of Project Farm videos through the years and love the channel. I do think it would be best to test out different MERV ratings and different brands but the cost of doing that is quite high and I don't have the budget for it at the moment, especially after my home flooded a few days ago. Hopefully some time later this year I can make it work. I installed a 3M 2800 in a friend's house a few months ago and noticed how many pleats were in that filters. They really pack them in there! That is definitely what leads to their better static pressure ratings. A lot of the online filters are cheaper but their build quality is lackluster.

[@nathancooley8459]

My father is a building inspector, he spoke with a product safety inspector at a convention that had worked on exactly this problem, testing the effectiveness of various home air filters. What he said was the best filter you can use in your home is the cheap paper kind, but then you spray them with a light coat of something like Lysol air freshener. The thin coating of oil from the spray captures airborne particles. You can then re-apply the spray every other week and replace the filter every 1-3 months depending on your climate.

[@The3DHandyman]

That would be an interesting test to run. Thanks for the comment!

[@christopherjohnson9001]

That’s similar to a K&N auto filter where you use, clean, and recharge using an oil-based spray.

[@clutteredchicagogarage2720]

Great video! I have a friend who has worked as a professional framing carpenter and then general contractor for maybe the past 30 years. In the past couple years, he started developing serious sensitivity to any kind of dust and a chronic, debilitating cough. When I pass by job sites in my city, I sometimes see masons grinding or cutting limestone or concrete with no respirator or dust mask of any kind. This is absolutely terrible for your lungs even when you're outside. Fine dust particles are really bad for your lungs, and I'm glad that people on KZbin are creating more content with ideas for dust filtration. I'm also glad that tool manufacturers in the past decade seem to be focusing more on better dust ports for various kinds of saws and grinders.

[@The3DHandyman]

Thank you! I have watched masons and other contractors do that same thing. That is part of the inspiration behind these ideas. I have an idea specifically for contractors that I hope to get to later this year.

[@albertshilton5336]

I suffer from the same thing. I worry about getting COPD.

[@BruceLyeg]

I had just watched a video of a guy building the Corsi-Rosenthal Box and was thinking to myself "self" (I thought) "how is that any better than just a single filter on a box fan"? Then when I move my eyeballs to the right side of the screen was your video, this video. Thanks for the excellent video demonstrating the difference between the various types of set ups

[@danielwatkins83]

This is about the 20th DIY air filtration video I've watched. Excellent information. I appreciate you taking the time to do these tests. Cheers

[@The3DHandyman]

I appreciate that. Thanks for the comment!

[@jimwillockx2278]

It is refreshing to see opinions backed by science and math. Thank you!!!

[@chrisgenovese8188]

This was very VERY well done! Between painting, woodworking, and metal working, dust collection and air filtration have been one of those things that I'm constantly tweaking and trying to improve. Unbiased and scientifically produced content is always appreciated!

[@The3DHandyman]

Thank you! More designs and testing on the way next month

[@CatRacer1A2A]

I found that by taping off the corners and making a shroud, my fan blades and grill stayed much cleaner. I use mine for household air in the cooler months when we can't open up for fresh air. I have 2 fans, both Lasko. I run the 4" Nordic pure filters. On one fan I used the metal shroud from a burnt up fan between the fan and filter. To my calibrated hand there is a noticeable increase in airflow. With 2 large shedding dogs and a fluffy cat, our home air always feels fresh and there are almost no lingering smells. Great video and testing. Thank you.

[@The3DHandyman]

Great feedback! I think the 4" Nordic Pure filters work quite well. Good call on the shroud, a lot of people use them. They are definitely good for keeping air from pulling in the front side. In my wind tunnel test they did not return an increase in airflow but that may be the result of how the test was configured. Thanks for the comment!

[@joedance14]

Interesting comment. Please clarify “metal shroud”. Not sure if you referred to grillwork that keeps hands away from blades, or the “box” of a box fan, or something different. Sounds like a “spacer” was placed between the filter and fan. I’ve heard or read that three or four inches can make for much better airflow. Thanks!

[@CatRacer1A2A]

@Joe Dance I used the box from a burned up fan. I just removed the guts and have taped or riveted the old shroud to the new shroud. There is a noticeable difference in performance.

[@joedance14]

Thanks!

[@kevinstory872]

i may not be the originator of the filter on fan idea but i have used one of these for a long time. the reason i put the simple design together 50 years ago was because of allergies and the outragious cost of hepa filters on the market. i have used that simple design for its filtration at low cost and white noise for tha long. its cool seeing how this may have turned into something else but the original idea is still the same, simple cheap and effective for a person with allergies to get a really peaceful nights sleep.

[@The3DHandyman]

You never know, you might have been the first! It's simple cheap and effective. Lot's to love about the design.

[@ColinMacInnis]

Just (literally just) finished building mine. Super satisfied with the design and function and threw some sawdust in the air to see it in action and thankfully it worked like a charm. I added a 2x4 frame at the base with a 3/4” piece of plywood as a base to give it more weight at the bottom. It moves and glides around the shop with ease. Thank you!

[@The3DHandyman]

Glad you like it! Thanks for the feedback. I'll be doing plans for quad filters in this same style later this week if you ever want to convert to a design that uses fewer filters.

[@assaissa]

Two main rules of building DIY filters: 1. Increase surface area of filters. In ideal world, you build infinitely large cube made of filters. The more surface area, the less energy fan need to make its maximum air flow. 2. Dont push air of the box, but rather suck the air out of it to room - like any CPU fans do. You can notice your laptop taking air OUT of it rathern than pushing it inside. Pushing air inside box makes the air stream turbulent - that is more resistance to air flow. When you sucking air FROM the box, you get laminar (smooth) flow, because there is no obstacles for air in your room (because room is big). The blades of fan must cut-and-scoop-and-pull air FROM the box, not pushing it there. For the filter, when you SUCK air off the box, the air pressure from outside of the box is distributed more evenly by filter surface than if when you pushing the air into the box, creating vortexes inside the box. In pushing scenario air will push the filter more in areas right next to the fan.

[@coldcitydweller]

Also pulling air from the filter box through the fan keeps the fan cleaner than pulling all the dirty air through the fan before it gets filtered.

[@iamtheconqueror]

I think he mentioned that in one of the earlier videos. Pulling air through the filter box where the fan is on the exhaust side means all the dust accumulates on the outside of the filters. If you bump into the thing with the fan off it drops the dust in the floor which kind of defeats its purpose. If you have the fan push air into the filter box then all of the dust is contained in the filter box. Bump away at it and no dust will be released

[@The3DHandyman]

I agree with rule #1 if you have no way to determine the quality of filter material. The harder part is figuring out what the filter is made from. Filter material has a huge effect on small particle filtration. I'll cover this in more detail in an upcoming video where I get into all these details. As for rule #2, this is true in most instances but there are some exceptions. I'll make a video on this concept soon as well because it's quite a point of contention. Until then, the short of it is that if you want to filter the ambient air in a large space effectively, point the fan upwards, or "pull" air from the box. This works well for all the reasons listed in the comment above. However, if you are producing lots of dust next to an air filter, the outgoing air from the fan will capture that dust and blast it all over the place. Not all of it will stay in the air column and that dust will be deposited all over the place. If you "push" air into the filter box, under some conditions, you can capture dust form the source before it gets blown all over the place. The source must be no more than 5ft from the filter for this to work effectively. This concept really only really works with the enclosed-motor drum fan powered version in this video, it should never be used with a box fan powered design (Corsi-Rosenthal, or single filter). You need a very large amount of filters in your filter box for this to work. If the volume of filter media is lacking, the turbulence in the air column inside the filter box has the potential to drive particles through the filters. The "Model-A" drum fan powered version does not evenly coat the filters in this configuration. The top 6 inches of each corner of the top row the filters is relatively clean in comparison to the remaining 90% of the filter area. Dust coverage overall is very even. As long as there is enough air supply for the fan to function normally, the blades "scoop and push" air in any direction you like. The total cfm of the fan is the same in either direction, push or pull. I have run a couple of these to show the benefits of both options but more tests are needed for the video. I hope to have it out in 2 months or so. Again, I would not recommend the "push" option for virtually all DIY air filters, especially those that use box fans.

[@joansparky4439]

@@The3DHandyman Will you also look into radial fans vs the axial fans you tested? And what blade design is best there (forward/ straight/backward)? And also into the power draw of all of those.. watts vs volume of air moved would be a good guide I think.

[@The3DHandyman]

@@joansparky4439 I will do all those things! Not in the same video, but eventually... I have a design for a blower/centrifugal fan and an inline fan in the works. Off the top I would say that the axial fans tend to be the most energy efficient but I'll have all the official numbers in the next few months 👍

[@andrejka_talking_out_loud]

The mind of a man is amazing and your tenacity doing all this testing is admirable.

[@ntsreviewsandvlogs9005]

If you’ve never used an air filter these are great. kzbin.infoUgkx_dppjvjF8BYEmPSDTcgCUdRsgWYLXNHN I ended up with three after starting out with one. The noise level depends on the 1-3 settings with how hard you want the machine to work. You can also upgrade the filters and get one better for pet hair and smells which is a must have in my home. I noticed the air seemed lighter and easier to breathe when running the machine for the first time. Works great every time. Highly recommended!

[@HyperactiveNeuron]

My brother is a mechanical engineer specializing in HVAC... He would need impressed with your thoroughness.

[@The3DHandyman]

The next video will be even more through! Too through maybe... that's why it isn't out yet... I keep adding tests on to the schedule.

[@barrylinkiewich9688]

I really like that circulator design you proposed at the end. I've got dust collection at device for most of my shop tools but it's obviously not containing the fines because any time I do much work I'm still getting dust settling.

[@The3DHandyman]

That's what inspired me to try these out in the first place. I don't like spending much time cleaning. The circulator seems like the most effective option for a small space. I actually planned on installing something a little more custom in a space that I had planned on moving into least year but still haven't... I did concept it out in this video tho. You might like it kzbin.info/www/bejne/hZm5iKakidJrn7c Otherwise the circulator is just a Model-A (original filter design) that has an extended box on it. I would recommend giving it another stack of filters if you push it up against the wall/ceiling tho. 6 Filters is borderline to few for this drum fan.

[@nyla3235]

Thank you for your video. I'm cleaning my basement in an old house and researching how I can best create cleaning of air. Your video has greatly helped my understanding of DIY options.

[@The3DHandyman]

Awesome! Happy I could help. I will put out a video on how well different brands of filters and different MERV ratings preform this weekend

[@BriBo24x7]

You should look at the video that Jay Bates did a few years ago where he used a furnace fan. I build this same setup and it moves a massive amount of air, and does it relatively quietly. It also uses 20x20x1 air filters and has a rolling base so you can put it next to whatever you are working on. Works really, really well, but I would be interested to try it with some of the thicker filters you tested.

[@The3DHandyman]

I have seen it. A guy just offered me an old furnace fan as well. I hope to have a video out that features it in 2 or 3 months. The current plan is to use a MERV 16 filter for almost HEPA performance. Thanks for the comment!

[@davidhaman9745]

​@@The3DHandyman-- I look forward to it! Except, I am considering using washable high quality filters.

[@The3DHandyman]

@@davidhaman9745 That's a great choice. They don't work as well as the disposables but they last for a very long time. I tested the K&N filters against smoke particles and they preformed fairly well. I am working on a modified filter kit that uses K&Ns for a prefilter then a MERV 5 canister for the super fine particles. I'll test this setup in the same way as the others. I will also be offering a build it yourself version of the Model-B in a few weeks or so.

[@joedance14]

@@The3DHandyman”...MERV 5 canister...”?

[@The3DHandyman]

@@joedance14 Lol, MERV 15 canister. This video is still in the works but should be out in a few weeks. It's been a rough couple of months with 100+ hour working weeks.

[@talltimberswoodshop7552]

Thanks for doing this. I bought a Harvey G700 for my 600sf shop and run it as long as I am in the shop even when not cutting anything.

[@The3DHandyman]

Nice air filter!!!

[@steveaustin5344]

I bet it's helpful to reduce pollen (thus hay fever) in Springtime and reduce smoke from wildfires too. Excellent video man. I really enjoyed the deep dive. I heard that some kids make these in schools too. What a great idea for a school project! Get kids excited about STEM.

[@steveaustin5344]

Presently, the best value ($/area) for MERV13 (1900) filters I could find via your Amazon link is the Filtrete 24x24x1. It's definitely worth comparing different sizes and quantities. The prices vary a lot.

[@The3DHandyman]

@@steveaustin5344 Thanks Steve! I am working with a local non-profit to make kits for my air filters. They have kids from a STEM school coming in to do the work on them. I'm really excited about it! The kits should be available next month. I plan to do a video on the different cost's per filter and the performance of different MERV rated filters. Lot of content opportunities in this space!

[@michaelwright1602]

It was getting stale in the house, various air cleaners, they don't really work that well, and are small. I have a Lasko box fan, went up to Home Depot and bought a $5 20x20x1 inch filter, duct taped it to the fan. I cannot believe the dirt it is actually sucking out of the air! In fact, I am SHOCKED! Damn thing works! And yes, I change out the furnace filter on a regular basis... In fact, I just changed it. Oh, I did subscribe! Fantastic video!

[@The3DHandyman]

Thanks for subscribing Michael! I have a video out on what filters works best for the single fan/single filter option. The low cost filters will pull dust out of the air but others work even better when it comes to smoke and extra small particles. kzbin.info/www/bejne/jnKtkJJ7Ys18gMU I suggest that you can just the fancy ones in your HVAC but it seems like its best to run them in a separate filter and keep the high flow filters in your A/C instead.

[@alvinsimpson1658]

Looks Like you Put a Lot Of effort into this project. I appreciate this. Alvin

[@Lucidity__]

THANK YOU for making this. I’ve been testing different diy air filter options for a while and this was very helpful!

[@The3DHandyman]

Don't want to tape one up? Check out my new filter kits! Watch the video: kzbin.info/www/bejne/m4qyp6GnpLxnfpI Buy the kits www.etsy.com/shop/The3DHandyman

[@captainhook426]

I'm stealing your current design, cutting down to 4 filters instead of 8 while using 4" filters. That should allow me to be low profile enough I can sneak it under a bench when the car needs to be parked in the garage. I don't see a link to the Anemometer. If you have one, I'll just order it for comparison. Or any other recommended option. Great video! Super excited for the next one!

[@The3DHandyman]

That's a great idea! The 4" filters may even preform better than the 8x1" filters. The original video for that design shows a 4" filter option for a moment during the animation. How do you plan to hold down the filters? That's one part I didn't give much thought to. Anemometer Link - Right now this one is the lowest price amzn.to/3OkzmhF Feel free to post the results of your test here!

[@robertzimmerman4685]

Doing a lot of research on cleaning the air in my shop,about 750 sqft 10’fch.this has helped, thanks , think I will do a 4 filter unit

[@The3DHandyman]

I've got a video on air filter performance as well kzbin.info/www/bejne/jnKtkJJ7Ys18gMU I'd suggest 3M filters or off-brand 2" filters for the 4 filter design. The air king fan also preforms 20% better than the lasko.

[@WillN2Go1]

Good video. Thanks. Something else to consider. I built a 'temporary' filter box over my floor furnace. These things are so terrible I pulled them out of my old house and we went without a heating system for a few years. It's basically a box hanging on the wall, with a 1" filter 20x24" on the bottom above the grate. Works great. It's also forced air, so it heats up my house much much better. At the beginning of the heating season I go into the furnace and vacuum out every corner I can reach. (I put a 3/4" aluminum pipe on a DIY adapter to get into the tight areas). Works pretty good, but there's still dust in the air. This year I took apart the small Lasko fan and cleaned the blades and grills. Huge improvement. So those filter boxes with the box fan pointing straight up? They will get dust build up like my Lasko, but also dust falling back down when the system is off. In a shop I would suggest a piece of cardboard as a cover when not in use. Also higher up is always better -- that's where we breathe. Even with my furnace filter I have two regular air filters. I find if I vacuum off the outside carbon filter every year I don't have to replace the filters for several years. I live in Southern California, in Los Angeles, so less heat is needed and there's more dust.

[@The3DHandyman]

Interesting info. Thanks for the comment!

[@ZadesLegacy]

I wish there was more videos like this! Your work and testing is so beneficial.

[@The3DHandyman]

Thanks Brian!

[@albertshilton5336]

I love this video. I retired and have a 24’ x 45’ wood shop with 16 ft. Ceilings and I am literally sick from wood dust. I caught up dust at night. My question is, which way should the exhaust go? Up would create a rain of dust that might recirculate through the filter. Down would kick up dust from the floor. Horizontally would work through an open window if I had one. The best solution might be several cubes with merv 14’s near belt sanders, table saws etc. What do you think.

[@GeeCeeAte]

Man these algorithms.. I have never searched for anything like this. Tonight I took a carbon filter and taped it to a box fan. This was the third video down when I opened up KZbin haha. Amazing vid though! Thank you!

[@The3DHandyman]

Thanks! I just tested a bunch of filters to see if which filter smoke the best. The 3M MERV 13 and 14 filters work really well on the back of a box fan. I'll also be testing a few more options in a new video that will be out in a few weeks. Here is the current one. I talk about 1" filters on fans towards the end... kzbin.info/www/bejne/jnKtkJJ7Ys18gMU

[@jonathanrand7767]

​I bet a lot of woodworkers would love to see you dive into alternatives to the expensive canister filters for their dust collection systems. Me, for example.

[@The3DHandyman]

Coincidently I will cover canister filters in my upcoming videos! 3 will be tested, including the Wynn and cheaper alternatives.

[@GrandpasPlace]

As someone who has built and worked with laminar flow hoods to create sterile environments, I would like to give you a couple of simple suggestions. 1) Use a squirrel cage fan. You'll get better airflow and they can be much cheaper if you source one from a used air conditioner system. 2) Use a $1 furnace filter on the intake side as a pre-filter. It is cheap and can collect the larger particles that will quickly clog your better filters. Assuming you keep the configuration, personally I think it would be better to pull air through the filter and out via the fan.

[@The3DHandyman]

Great to get comments from people experienced in the industry! Thanks for the comment A used blower motor of that size is definitely a good find. It's nice that the static pressure info is also available for this type of motor. The prefilter idea is a great one. I am experimenting with some washable fabric options at the moment. Something that will last years, hopefully. I just finished graphing the numbers and in a 4400sq.ft space the "pull" config outperforms the "push" config by only 10% in a smoke test (30 minutes to good air quality from a hazardous level vs 34 minutes). I actually expected it to be a larger difference that that. Given that I use it as an oily vapor sink, a paint booth, and a dust removal station, etc... I still like blowing air into the filter box despite how unorthodox it may be.

[@neilbaltes3469]

Terrific info!! Your design with the CAT fan is the design I'm gravitating towards. I'm a DIY'er and occasional maker. I like this design as it offers portability with really good dust control. When doing a home improvement project I can keep dust from entering other parts of the house; certainly down to a minimum. Thank you again for all your efforts...the education is awesome!!

[@The3DHandyman]

Thanks for the comment! I think my original design should work great for that. You can park it in a doorway and that should prevent any dust from escaping. I have also used it in a dusty room for end of project cleanup by closing the doors, putting the filter in the center and using a leaf blower to kick up all the remaining dust after vacuuming. Definitely wear a dust mask for that :)

[@neilbaltes3469]

@@The3DHandyman Great minds...Milwaukee bench blower is on my list. I've bought a nice mask made by Trend. It's comfortable which means I wear it. Now, I just have to find the time to build your CAT version. LOLOL

[@The3DHandyman]

@@neilbaltes3469 Finding the time is always the challenge! That Trend mask looks pretty nice! My 3M is just ok as far as comfort. I'll need to try some new ones at some point.

[@jacobbaxter2278]

This has to be one of my favorite YT videos. Scratches an awesome hobbiest niche, an awesome public health niche, and lays out everything necessary to replicate!

[@The3DHandyman]

More on the way too!

[@jacobbaxter2278]

@@The3DHandyman I'm addicted now! Love all of the new videos. I've used tons of the affiliate links. Bought the AQM. Interesting conclusion on 3M vs Nordic Air. Could you wind-tunnel test 2 fans stacked? I'd also love to see decibels be a top statistic you present too =)

[@The3DHandyman]

@@jacobbaxter2278 Stacking axial fans creates a lot of turbulence and therefore doesn't really improve results. I just tried serial inline fans and expected more of an improvement that I ended up getting. Where those really shine appears to be running them in parallel. That video should be out next month! Here's the sound info I've collected so far. The numbers are arranged from high to low speed. Background sound 40dB Lasko @1 ft - 63, 60, 55 Air King @1ft - 68, 66, 61 Air doctor @1ft - 64, 58, 52, 45 Maxx air @1ft - 71, 67, 57 Caterpillar @1ft - 71, 67, 63, 57

[@jacobbaxter2278]

@@The3DHandyman Makes great sense. Thinking about helicopters, I wonder if that's why they do counter-rotating blades. I wonder if flipping the direction of spin would allow serial gains vs parallel =) Might think about how to do this appropriately

[@mathieubarrault450]

I love this serie ! thank you for all your tests. (and thank you for showing the plastic peeling of the remote, so satisfying ^^)

[@The3DHandyman]

Glad you are enjoying it. More to come! Lol, yeah, I didn't have any footage for that moment in the video so I threw that in hoping that someone would get some satisfaction 👍

[@williamriley-u5l]

Nice job dude. I probably would have goofed with the placement of the hinge and filter also. One suggestion would be that instead of drilling a big hole and passing the plug end through it, drill a small hole just large enough to pass the cord through then cut the cord so it won't show from the inside and splice it together again. Then you don't have a large hole with a wonky patch on the inside. Everyone has a different way to skin the cat, right? I like it.

[@The3DHandyman]

Thank you! I like that pass-through method just fine. It's a bit more involved though

[@lanzer22]

Note that if your goal is to have a home air filter, high CFM is not necessarily a must. Leave a cheap 20" fan running on low for a few hours and you can already drastically lower the AQI to less than 1 as long as you have plenty of filter surface area. Workshop filtration is a completey different matter of course.

[@The3DHandyman]

Very true! The sound the high end fans make is not fun to be around in your livingroom or bedroom, for sure.

[@dargunsh7156]

​@@The3DHandymanhello, do you have discord by any chance? I'd like to get some help with building my own filter. I have a high cfm fan of about 4000 to 8000 cfm depending on speed, 50cm(19,6inch) diameter blades How many filters do I need? I only have two 60by60cm filters. Would stacking them together work or should I put them on different parts of the box?

[@The3DHandyman]

@@dargunsh7156 Hi! I don't have a discord yet, but I can answer your questions here or through the Etsy message system if you want to send pictures or something. 4000-8000cfm is a lot. If you are using 60x60cm filters, I would suggest using 6-8 of them side by side. The more filters there are the better it will run. The filters can be arranged in a box configuration or in a line with one another if you want top make a ceiling mount. The filters will cost more up front but they will last longer if there are more of them. If you still have more questions, just ask.

[@dewitubeX1]

Dude your channel is going to bloom, this is a well put together video. you're the man.

[@AndrewHelgeCox]

I've been thinking about making filters with smaller fans, sized to match the airflow possible through one of these filters. So, rather than adding eight filters to one big fan, give each panel it's own little fan, perhaps a large PC case fan, with a slim profile frame. That might let me wall mount them for unobtrusive background filtering or deploy them in a cluster around a dust source temporarily. To equal the flow rate of your big box, divide the flow rate of the fan you have on it and locate eight fans, each with one eighth of the airflow.

[@The3DHandyman]

That a cool concept! It looks like you can get 100CFM out of a good 200mm case fan. Since it's a low volume of air the filter shouldn't produce that much static pressure to slow down the flow. It will also be far quieter than anything in this video! haha. Let me know how it works!

[@AndrewHelgeCox]

Maybe fans from dumpster / e-waste PCs would be required to make the project cost competitive.

[@The3DHandyman]

@@AndrewHelgeCox Good point. They don't have to look fancy. I have a high CFM server fan kicking around that fits that description but it sounds like a jet engine!

[@Shamustodd1]

Thanks for the video! This points me in the proper direction for a DIY solution. Currently running the box fan with 1" filter option along with the shop vac hooked to any equipment I can hook to. It's better than nothing but Just better. I needed a something better but wasn't sure which way to go. The data you've shared paves the way for multiple filters with a powerful fan. Again thank you.

[@daveknott4563]

Very good video. Just sub'd and looking forward to more. It's detailed, yet condensed, rational, cost in mind, and hits that 10 minute sweet spot.

[@amtb70x7anunkwn9]

MOST Excellent and very informative. As a former A/C Duct Mechanic I see you have done your homework. 🙂👍 great job Sir! Thank You.

[@The3DHandyman]

Thanks! That means a lot

[@Eilaithen1]

Very cool content. I could pick up a cheap filtered for in home use but have been considering the diy option for a while. I would probably got the hepa route for the home though. You definitely earned a sub from me looking forward to more content!

[@The3DHandyman]

Thank you! I'll be testing a 20x20x5 MERV 16 filter on a box fan soon. I actually tested some HEPA filters as well but haven't finished that video either. I need to add more charts here but there is a bit of into on the tests already the3dhandyman.com/what-is-the-best-air-filter/

[@leisahayes4890]

Well thank you Mr. Video Game Designer.... you have done a fabtabulous job in providing us with "need to knows" on air filtration. Fr it's been very educational, Impressively thorough & enlightening. Your descriptions & DYI's have been meticulously thought out & designed. It has made me def wonder about my box, fan, & filter i paid $85. for on Amazon. 🤔 😮

[@The3DHandyman]

Thank you, Lisa! In the end, any air filter is better than none at all :)

[@scrumptiousjdp]

Hi and wow, this is awesome! Have you tried the passive home filtration system that uses a filter in a window with a cross breeze? Can't find that video now but I saw it on KZbin a couple years ago.

[@The3DHandyman]

That's a great idea! Many years ago I had an idea to make a product that was essentially that. I just couldn't figure out how to make the filter adjust to all sizes of window. There are lots of filters out there that could fit your average window....but maybe I should take another crack at that idea and make a video on that too. Thanks for the thought!

[@raymondbunkofske4702]

Something to remember is that the ASHRAE test, where the MERV ratings come from, uses a 100 feet/minute *face* velocity. This is calculated by figuring out the area of the media, which for a pleated filter is 2-3x more than the size of the filter, and dividing that into the measured flow. So to get the listed efficiency your face velocity needs to be no higher than the 100 fpm test velocity. The advantage of the commercial units is you can cascade the filters. I use a 40% ASHRAE filter as a pre filter and a 95% DOP (about MERV 15) final filter. My setup cost more but it’s much quieter which is worth it to me. The other thing to consider is to either clean your filters often (before you can see they’re dirty) or isolate them from the vibration of the fan. If you look at SEM photos of dirty filters the dust particles look like dendrites, the fan vibration can shake them loose and release the dust back into the air.

[@The3DHandyman]

Good info. Thanks for the comment!

[@jakobthomas3587]

i have been looking for somebody who tested different fans and speeds Thank you very much for all this great info!

[@The3DHandyman]

I was surprised someone hadn't done it already! Thanks for watching and commenting!

[@ohtoah]

Good Job, Beneficial truthful information. Crossflow seems to be key in a work area. All so ducting from the proximity of the source of the material to be removed from the air. I have used restaurant grease hood fans, they have large cfm and used ones can be found very cheap, with the bonus of being explosion-proof.

[@The3DHandyman]

That's good info. I have been working with a few ducted designs lately. It's a bit of a different setup than what you describe but the results are quite good. Those shaded-pole motors are top notch. I've been wanting to test with them for quite some time. Maybe one day!

[@robertdouglas4293]

Nice, in design stages with easily accessible stuff, this is going to be fun, going to make one for a neighbor with breathing problems, Thanks for the info!

[@ShreddedShredder0]

I wish this video existed ten years ago. I used to make my own air purifiers with the Lasko fan. Also, the Lasko fan (and all the other in-house brand clones from retailers) likes to walk across the room if you have a smooth floor.

[@The3DHandyman]

That's a amusing thought. The fans do seem a bit unbalanced at times. I just made a single filter design that incorporates rubber vibration dampening feet that would help with that issue. In general these work great for in home use if paired with the right filter.

[@timdelpercio2398]

Have you considered testing a standard home shop vac running with a hepa filter and bag? Obviously, the performance would not be anything outstanding (like your designs), but maybe it could be an option for someone working in a garage who already has this setup sitting there and would otherwise do nothing. Amazing video!! Thanks so much!

[@cm3462]

You really set the bar for DIY air filter videos. Just wanted you fyi you on one option: the Healthy Home Guide channel does a version with an ultra-quiet EC motor fan. For people like me, trying to filter dust in a quiet office, this is an ideal variation. He gave you props in his video for your groundwork -- maybe you could do a video / kit with the AC Infinity fan or similar, and send a nod back his way. PS I have built his version and it really is deadly quiet.

[@The3DHandyman]

Thanks for the heads up! I appreciate the comment, it just got lost in the pile of comments from my latest video. I'll have to check that Healthy Home guide video out. I like the AC infinity fans for just about every application. I am hoping to reach out to them to to get some demo units because they are a bit on the expensive side. Hopefully I'll be able to feature their fans heavily in the next video 🤞

[@woodworksbygrampies1284]

Hola!🖐By far the best video I have watched on the topic. This is also my very first video of yours I have come across. I'll be watching more and more of then now. Thanks for all your work and effort then sharing your findings with us all. Take care and have a good one, Adios!👊

[@robertkerby2581]

I really enjoyed your very informative video! I would have liked to see you build one of those filtration systems. Well done, Sir!

[@The3DHandyman]

Thanks you. One day I will get around to more builds!

[@idontcare1102]

this would be great for allergy season but i may not use for workshop thanks

[@gdreilly]

Great video! Remember doing tests like this while in engineering school

[@The3DHandyman]

Thank you! I wanted to be an engineer, then along the way I discovered I couldn't do Calculus! So much for that, lol

[@Jakewarb]

Thank you for going through all of this testing! I must say, i did reverse engineer some of your numbers to try and get the max cfm for 16x25 filter and a few other sizes. I've watched this video about 6 times all the way through, and i'm sure i'll watch it a few more times. now i feel like i need to get an anemometer. Would love to see results in the wind tunnel using the pull method and see how much vacuum it makes. Thanks again for doing all the dirty work, loving these videos.

[@The3DHandyman]

Thanks! I already tested that but haven't gotten the video done yet. Some of the results are up on my website though with lots more to come... the3dhandyman.com/what-is-the-best-air-filter/

[@CueBall909]

Stumbled across this video and it was very informative. I'm looking to setup something similar for my shop soon. On your shroud testing, you should try removing the cover from the King fan and putting cardboard "fillers" in the four corners. That way you have a shroud at the location of the blades. If it works, and I suspect it will, it would be easy to 3D print some really sturdy pieces and improve performance at very low cost and effort.

[@The3DHandyman]

Already finished the parts for this, just need to run some tests. The video should be out in a few weeks!

[@hyunkim17]

Not sure if somebody said this already, but you can check if the shroud is blocking all the air from coming in by sliding a piece of paper or tissue from the edges. Shroud shown in the video might be covering up more than necessary reducing the flow a bit. Although I'm not sure if it'll affect it much and it's more work with trial and error, but you can see more precisely at which point the vortices are blocked and not blocked more than necessary.

[@The3DHandyman]

I plan to do a video in this sometime in the next month or two. I'll include the answer to your question with lots of testing!

[@birdsoup4355]

this information is helpful for cleaning my hobby room especially when i airbrush.

[@Storyholder23]

Great video, thorough test, good humor and humility. Watching more in the series right now

[@The3DHandyman]

Awesome! Thanks William

[@johnnymerchant]

Interesting. I was just thinking of making a DIY air filter by sticking AC filters to the back of my big orange fan, and now youtube recommends this video. Good timing, algorithm.

[@MM-cg8cg]

You deserve much more likes and views. Thank you so much for your thorough test.

[@vigilante_stark]

Thanks for this video man. I'm fed up of dust myself and trying to solve this problem.

[@The3DHandyman]

Happy to help! I am wrapping us filming on the next series which tests a bunch of air filters to see which captures the most small particles and gets the highest airflow. I hope to have the video out in about a week or so. VOC reduction will follow! Testing a bunch of ideas for that too.

[@vincentrobinette1507]

The set up I'm using, is a 5-filter Corsi-Rosenthol box, using 4) 20 X 25 X 1 filters, and a 20 X 20 X 1 on the back. Place the box on a wire kitchen rack, 16 X 22 X 10" tall, with the fan blowing towards the ceiling. Placing this apparatus in the middle of the shop will help keep everything dust free. Run the filter continuously. By placing this in the middle of the shop space, it creates a toroidal air circulation, and is the most effective way for a single box fan to cover the largest space possible. I'm running MERV-12 filters now, but I will be replacing them with MERV-I3 filters, with the 4 sides being slightly larger, at 20 X 30 X 1. That extra 400 Sq. In. of frame area should help compensate for the extra restriction of the finer filter media. (Besides, the 30" tall filters were the same price as the 25" filters, so that extra area didn't cost extra)

[@The3DHandyman]

I love the toroidal setup. The center of the room is really the best place for it. I want to do a video on filter placement in the next few months because it is really key the the effectiveness of the filter. One of my best preforming kits is a 20x30x1(or2) deign. The static pressure inside the unit drops to about zero with these bigger filters. You are also right on the price, the 20x30s are quite good on cost. Thanks for the comment!

[@pleappleappleap]

I just remembered I have a very large capacity Air King whole house fan I'm not really using. Project time!

[@AK88.]

You took the cake man well done keep at it!

[@DerClaudius]

Thanks for the extensive tests... I've been thinking about what to get exactly forever..

[@The3DHandyman]

Any time! Each option seems to have it's own benefits outside of just airflow and filter ratings. It's a lot about what you are doing and where the fan will be placed in the room. It's the sort of thing that can take exactly forever. I hope the video finally got you going in a direction!

[@klave8511]

This is a really good video. Thanks for the level,of detail you went to. For a shop, the filter and fan is really only a part of the solution, to be effective you have to control the airflow to the filter, you have to move the air across the work area and to the filter. This means you need some blowers and ducting to direct the air across the work area and then the filters capture that air. You did allude to this at the end. Without this you are just sucking air from near the filter. You will see this in any properly designed air conditioned application especially where there are shops with doors that open to the outside and the cost of air loss (warmed or cooled) is important. You did start along this path when you tested the dust that actually enters the filters but you left it to the fan to suck the dust laden air with no real control. You must control the air flow. You have started looking at the problem from a system viewpoint by including the dust collection and the cost of ownership. If you do this a bit more and realize that larger shops need different equipment to small rooms. For example, a pre collection system may be justified, a basic cloth filter that can be cleaned or a cyclone that can take some particles out of the stream so that the filters last longer. And actual measurement has already been mentioned (particle counter) to gauge when the filter is blocked, this will also affect cost of the filters over time. Many modern cars tell you when to replace the oil based on you usage, they save money this way, a similar system can be used for air filter replacement. If you can’t measure the particles then you can measure the pressure differential or the airflow rate to tell you when to replace the filter. This needn’t be a fancy electronic device, a simple manometer or even just a flap with a a weight can be used to indicate when airflow is reduced or differential pressure (across the filter) tells you the filter is now too full to filter properly. I did repeat some stuff you mentioned, I hope you don’t mind the repetition, I think you are doing great work here, many thanks.

[@The3DHandyman]

Thanks for the comment! There is a lot of good stuff in there that I hope to cover in a future videos. I did a smoke test in a recent video (and I plan to elaborate on this in an upcoming video) that tests to see how well the air is filtered at 15ft away from the device. I will also be testing dirty filters in an upcoming video but the testing schedule is getting very full with all the requests from people. So, hopefully that will be out in a month or two. Pre-filters for all these designs are also a work in progress. The high MERV filters are great but expensive and keeping anything out of a landfill for as long as possible is always the best option. As for controlling the movement of air in the space, you are absolutely right. I had hoped t move into a new shop last year and test out this design. Maybe I will one day. We will see. The owner of that building has shut down all current construction unfortunately. Anyways, here is the link. At the end I talk about the air filter system kzbin.info/www/bejne/hZm5iKakidJrn7c

[@jaycustin7002]

First off - very well prepared and presented, but I did want to make one observation. In your video (clearly shown from 9:32 - 9:47) you have the air pulled INTO the fan and out through the filters. The Corsi Rosenthal box is designed (and intended) to flow in exactly the opposite direction, i.e. pulling air into the filters and then out through the fan. That said, clearly YOU need it for drawing dust away from what you're doing and into the filter as effectively as possible. I understand why you've elected to use the opposite air flow direction as you want to reduce dust you create from "escaping" the unit as opposed to reducing virus-laden aerosol particles from the air.

[@The3DHandyman]

Thanks! Yes, that is my preferred configuration for this filter unit. I find that it helps keep dust from being accidentally blown into the air. That said, the fan can be pointed in either direction for personal preference. I talk about it a bit in the original video kzbin.info/www/bejne/nJrblWqCptOKpdk The other benefit of blowing air into the filter box is that the thick layer of shop dust on the filters that collects is on the inside rather than the outside of the box where it can be easily disturbed. For virus protection, this is not an issue at all. I am working on some air filter kits that function like a corsi-rosenthal for shop and in home use that focus on pulling air through the filters first before it passes through the fan. I should have a video out on these in a month or so. Would love your thoughts on those as well 👍

[@shadowminor]

I think this is the first video I have seen someone mention the shroud need to be inline with the blade. ! idea you could look at that wouldn't be too terribly expensive is a small scale filter system for desk work space using PC fans.

[@The3DHandyman]

I have a design for a desk system that I'll be testing soon. What sort of work are you using it for?

[@operator8014]

I've always been impressed at how much you can pull out of the air with just a box fan with a 1" filter taped to the inlet.

[@michellemajako]

Finding your video after I bought the Lasko and the return window closed. That checks out.

[@The3DHandyman]

That's ok! The lasko is still a solid fan. It is also more quiet than the Air King if that helps :)

[@What_Other_Hobbies]

I was about to go to sleep when I saw this upload, and there is no reason to not watch it right away. I’m leaning towards the vertical push design with maxxair fan.

[@The3DHandyman]

Awesome! That design worked great for me for the 3 years I used it. Never even changed the filters until I shot the "update" video on it. It is a bit more powerful than the Caterpillar fan but do keep the motor housing clean... Maybe I can get around to make a 3D printed housing for that at some point. It's been on the To Do list for 4 years now...

[@What_Other_Hobbies]

@@The3DHandyman I have a lot of things on my todo list as well, but new projects always sneak in before them. I am currently getting close to finish a dining/gaming table build. Once that is done, I do need to solve this dust problem and get my shop clean.

[@The3DHandyman]

@@What_Other_Hobbies Hah, yeah. New projects always seem to take precedence. I have a fairly large box of things I may get to some day. The air filter build only took 1 day. Not to bad as far a projects go. And you don't have to spend twice as much time filming yourself doing it!

[@JPToto]

This super timely since I'm about to build some kind of air cleaning system for my garage shop. Well done!

[@The3DHandyman]

Glad I could help!

[@sdunca4864]

Im using your builds along with Bill Pentz and D C Knives to fabri-cobble a metal grinding dust control system- Won't lie- shameless plug- that anemometer would help a lot - I get a lot of value out of your builds and content- thank you for the opportunity to look over your shoulder and learn.

[@The3DHandyman]

Awesome and thanks very much! Will keep you in mind for the anemometer. I will need to find an online number picker or something to figure out who wins the unit. If you don't happen to the the winner, they are pretty fairly priced amzn.to/3OkzmhF Grinding dust is pretty intense. The place I used to work at had piles of it everywhere. So much cleaning involved. I wanted to work with them to develop some dust control concepts but there wasn't any interest from management.

[@Arc-]

Thanks for doing this. I am building 3 of these for my house and used your amazon links to purchase. Appreciate your efforts!

[@The3DHandyman]

Amazing. Thanks for your support!

[@alsnyder1660]

very well done. Thank you. I have an amateur comment ... I've read that part of why a proper hepa filtration system works so well is due to the high speed of the air moving through the filter media, causing turbulence and causing even small particles to collide with and get trapped on filter fibers even though those particles were smaller than the openings in the filter. If that is indeed true, adding more filters to make the box does increase airflow some but would significantly decrease the speed of air moving through the filters. Perhaps for the purposes of people making dying filters thus is not of concern but I suspect that although the box filters MORE air it does not filter that air as THOROUGHLY as a system moving air faster through its filter.

[@The3DHandyman]

Interesting concept, I'll look into it for my next video on filters!

[@familhagaudir8561]

So many options. Great comparaison not found elsewhere. I just need to reduce allergens in my room. I will try to find a 4 inch filter at a reasonable price. Difficult here. The fan itself is close to $90 CAD here sadly. 8:30 This chart is amasing. Thank you so much.

[@jmpattillo]

This series of videos is a real gift. Thank you.

[@The3DHandyman]

Thank you! There are more to come

[@brettgl21]

Thank you so much for doing this video. I have been trying to figure out what to do about my dust problem. I am going to build one of the big ones like you use. Thanks again.

[@The3DHandyman]

I'm sure you will like it! That filter has worked well for me over the last 4 years.

[@stevenwilson8106]

This is an amazing video, thank you. I was drawn to your video because I have a small but powerful unit, already, but with no filtration at the moment. It has a good fan/motor that I had from another project. It was not originally an air purifier but it has a good housing. I thought it would be fun to do a DIY project, and to save money, and I thought that I would try to make a Quality Hepa filter and a granulated activated charcoal filter as a project to do with my grandson. Your video is giving me a great start. Thanks for the education!!

[@The3DHandyman]

Awesome! I think that sounds like a great project!

[@chriskrawczyk2589]

Great info, I got to build myself one of those.

[@willshen5051]

Absolute great test/build process! My questions is, have you ever tried other options of fans, like using a few fans in series to boost the wind pressure, or using a centrifugal fan?

[@The3DHandyman]

Thanks! I plan on testing inline fans in series in the next few weeks. I am also working on a design for a centrifugal fan that was pulled from an old furnace. They will be put through all the the same tests as the ones in this video. Say tuned!

[@Tennababy]

very interesting, saw some videos as well of turning a pc into a filter too. thanks for the vid

[@The3DHandyman]

I have seen that concept too. Pretty cool for sure. I'll do a test of that at some point.

[@weefunkster]

These videos are top notch man well done. I had to make a comment just to let you know you are on the right track, keep her lit.

[@joedance14]

After watching and rewatching a number of videos lately about diy air cleaners, a couple of things caught my attention, issues and ideas perhaps worth mentioning: At some point in the comments - this video, I think - you responded to a viewer that you were interested in the idea of using two fans in a push-pull arrangement. I’ve kind of wondered about that too. At some point in the video or comments, you remarked that the drum fan atop the box of furnace filters could be set to pull air in through the filters and out through the fan, OR the opposite. Furnace filters generally are designed for air flow in one direction. You probably know that. That also applies to canister filters. They are designed to pull air in, leaving dust on the exterior, or to push air out, catching dust on the interior, as in the case of dust collectors. I have no idea what would happen if filters - furnace or canister - were used in the incorrect orientation, but manufacturers suggest failure, I suspect damage to the pleats and to the structure, creating leaks. Perhaps you are aware of these issues; some folks will not be. Q1: instead of placing the drum fan atop a box of furnace filters, what about placing it atop a canister filter? Q2: would there be a performance difference or advantage/disadvantage to a pull arrangement vs a push arrangement? In the case of a Corsi Rosenthal air cleaner, the consensus seems to be that a pull arrangement is better. However, I don’t believe I have seen any particular tests, data or summary explanations anywhere - ie, no reasons. Q3: Inexpensive commercial air cleaners appear to employ small axial fans. Better commercial air cleaners employ relatively small centrifugal blowers, aka squirrel cage blowers. Dust collectors employ fairly large impellers. My understanding is that a furnace blower is far superior to an axial fan, for an air cleaner. What about the impeller? Is there some reason NOT to use an impeller for an air cleaner? Q4: This is actually an idea, and a variation on it, something that might be worth testing - or perhaps there are good solid reasons against. Here goes: a Corsi Rosenthal air cleaner on the front end, to act as a pre-filter, a canister filter on the back end, and a fan in the middle. Variation 1: dust separator on the front end. Variation 2: a second fan up front. I’m still learning the ropes of woodworking, finishing, dust management, etc., so please bear with me. I would really appreciate your thoughts. And please, I make mistakes all the time. I am not averse to the truth. I’m retired, well over 70, and tell my students that someday I may figure out what I want to do when I grow up. For now, it’s this - learning, trying things, repairing old tools, making mistakes, learn some more. Stay well.

[@The3DHandyman]

True, it is always good to orient the filter in the direction of airflow. I casually mention this as few times in videos but could be more direct. Good though about the canisters also having a correct direction. 1) I just wrapped design on this concept. It's a Model-B with a DIY canister upgrade. I'll cover it in more detail in my next video. Here is a link, there are a few pictures of this configuration www.etsy.com/listing/1373712349/model-bc-air-filter-kits 2) When using a drum fan on a Model-A (the 8 filter design) performance up close is superb when blowing air into the filter box. So, if you have a dust source that is within 5 feet of the filter, this works great. I use this setup exclusively because I use this filter as a dust bin for cleaning parts. However, this configurations is much worse than blowing air out of the box if the dust is hanging in the air over a large area. If you want to filter the ambient air in a room, blow air out of the box only. This is twice as effective because it causes a significant increase in circulation throughout the room which helps bring dust laden air back to the filter. I've tested this but haven't made that video yet. I suspect that the same principle is true for filters other than the Model-A. After all what direction do all professional air filter blow? Out of the box. 3) All of these fan types mentioned have their various benefits. Axial fans are cheap, move a lot of air with little energy requirements but they need to run with almost no resistance for optimal efficiency. Inline duct fans cant move as much air as an axial fan but they are better at handling static pressure but pull more power. They can also be ducted, which is a huge plus for many reasons. Blower motors have the highest power requirements but can handle the most static pressure. They are also pretty expensive for high CFM models unless you can get a second hand furnace blower. All of these have good use cases. I'll table about inline fans in my upcoming video. The blower fan video will need to wait. I did get a second hand blower tho! So, that's ready to go. 4) This is exactly what I put together for the Model-B. I love the idea. The outer filters act as a pre-filter (You can also add a 2nd pre-filter to them for triple filtration). The outer filters can be cheap MERV 8s or washable K&N furnace filters for even more reusability. I wont know for a long time, but I thing this setup could last for 10 years without a filter change. Words of wisdom there! I doubt I'll ever grow up in that respect. Thanks for the comments!

[@joedance14]

@@The3DHandyman Thank-you for getting back to me. Really appreciate your testing and insights. Stay safe!

[@joedance14]

@@The3DHandymanUpon further reflection, I realized that the push-pull arrangement would not work. In a push configuration, a fan pushes air into a filter (canister, Corsi Rosenthal, filter box...), creating high pressure. That forces air out through the filter(s) and captures dust on the interior. In a pull configuration, a fan sucks air out, creating a low pressure zone, that pulls air in through the filter media, capturing dust on the exterior. A push fan and a pull fan installed at opposite ends of a filter (canister, Corsi Rosenthal, filter box...) cancel one another out. However, the idea of a “pre-filter” and a fine filter, still has merit. A fan in the middle should - in theory, given enough airflow - work. I previously suggested a filter box/Corsi Rosenthal on the front end, and a canister filter on the exhaust side, but they could both be canister filters, or filter boxes, etc. The real issue is airflow. If furnace filters were used at both ends, the exhaust side -the fine filters - should be thicker, or larger, or more plentiful, or all the above, so as to avoid choking off the airflow.

[@The3DHandyman]

@@joedance14 I have accomplished this in a different way with my updated filter kits. Rather than a Drum Fan, I use an Inline Duct Fan which can have a duct and additional filters installed on it. These fans aren't quite as powerful, as the Drum Fan, but the ability to duct the air has huge advantages which outweigh the power loss in some cases.

[@joedance14]

@@The3DHandyman Sounds good!

[@socapots]

Excellent Video. Thank you for sharing. I am gathering information for a filter system for a garage/smoking room. This is definitely helpful.

[@The3DHandyman]

Thanks! I just did a video on removing incense smoke from the air with a lot of different filter brands. I think the 1 stick of incense burned in the test is equivalent to about 3 cigarettes for comparison purposes. Here's that video is you haven't seen it yet kzbin.info/www/bejne/jnKtkJJ7Ys18gMU

[@Killer_Space_2726-GCP]

I only have 3 filters for my box fan, but for filtering the small amount of highwah dust that makes its way into my apartment, this should be good enough until I get more! I'll make the cube design, with 3 sides and go for it.

[@The3DHandyman]

3 filters should work just fine for that purpose. You can just cover the last side with an extra piece of cardboard

[@Killer_Space_2726-GCP]

@@The3DHandyman That's what I did, will test it today. Wifey would have rathered we got a real air purifier, because this is a big box!

[@The3DHandyman]

@@Killer_Space_2726-GCP She may have a point! Haha

[@rowneilborja3385]

Very interesting, I've built a quick and dirty air filter box using a lasko knock off fan but I put the fan in a box and have the filters 1 inch away from the back of the filter. I actually have 2 filters on the box, one in front of the fan and one in back. The drop in wind speed is VERY noticeable but otherwise it seems to do pretty well. The space that I'm filtering is also pretty tiny so maybe it's fine just because of the smaller space.

[@The3DHandyman]

The size of the space does play a big roll in how well the filter preforms. The smaller the better in a way. A cardboard shroud could help air from being pulled in the wrong way and making that fan dirty in place of a filter on the front side. It may not increase performance of the fan but it should slow down air flow less than the front side filter.

[@leahdrees5102]

I severely asthmatic and recently moved, my throat has been really tight and I've been struggling with my asthma worse than ever before in my life, really hope I can afford to make my own filter system soon

[@The3DHandyman]

The lowest cost option may be a Corsi-Rosenthal box with a cheap box fan (~$70) and 3M MERV 11s or a single box fan and a nicer 3M MERV 13 or even better MERV 14 (~$40). They all work pretty well for spaces up to 500sq.ft. I talk about different filter option in this video kzbin.info/www/bejne/jnKtkJJ7Ys18gMU If you try one and it works or doesn't work for you, I would like to hear about it. There are lots of allergens out there from mold to pet dander and wildfire smoke, these can help but may not be the whole story. Carpet cleaning and disinfecting may help if you are in a rented space... sometimes you can get the landlord to replace the carpet. Some friends had a lot of breathing issues and then maintenance found a lot of mold in the ceiling. These might be some things to explore if the issues are caused by your living space.

[@steveboyle6891]

Wow! Very impressive video! Really well done 👍👍

[@daviddawkins2829]

Here's an idea. Reverse the Cat fan. Instead of sucking dust through the fan and pushing dust out of the box, you can keep your fan clean and have a visual check on your filters. My box is set up this way and I vacumm the excess dust off as needed.

[@The3DHandyman]

Fan direction really depends on how you want to use it. I've also taken to vacuuming dust off the filters and will do a video on that some day soon. Thanks for the comment!

[@joedance14]

Decided to look at this video again. Great work, really impressive!

[@The3DHandyman]

Thank you! This video will also get an update with loads of new filters and configurations tested.

[@steventrott8714]

Thanks for your hard work on this. Very impressive for a programmer!

[@l.slayer551]

It was fun to see the mushroom sculptures pop up. I’ve constructed filtration devices for mycology and currently run a squirrel cage fan through a 12” thick HEPA filter housed in a large plywood box to create a clean envelope of air within which sterile mushroom cultures can be worked on.... so it’s always interesting to look at various air filtration systems people have designed for their purposes. Cool video.

[@The3DHandyman]

I have seen these devices pop up on Etsy recommendations lately. A 12" thick HEPA filters is a beast! How long do those last under those conditions? Thanks for the comment, interesting stuff!

[@l.slayer551]

@The 3D Handyman, Under lab conditions a filter like that can last a long time. Ten years of daily use isn’t unusual with proper design. I constructed my current unit as a two-stage filtration system. Air is pulled through a 14x14x1” MERV-13 pre-filter by action of of blower motor contained within a sealed box. From there the air is pushed into the main filtration plenum before exhausting into the working space through the 12” thick HEPA. That MERV-13 filter is primarily used to preserve the longevity of the HEPA... Although it also helps down-regulate airflow into optimal ranges for this kind of work, which is generally considered to be 100 feet per minute and with as little turbulence as possible. So it acts as a scrubber for the whole room by changing out the air about every five minutes at that flow rate, but the main objective is to create an effectively sterile work zone directly in front of the filter.

[@The3DHandyman]

@@l.slayer551 Thanks for the long reply! I am discovering the various benefits of low turbulence as I'm running through a bunch of sanding tests. Do you duct the air out of the filter to another side of the room. Is there a diffuser on the outflow side?

[@l.slayer551]

@The 3D Handyman... Ok, I totally understand if this falls into the category of TLDR, but it’s kinda fun to geek out on these things. 😂 So no, I don’t have any ducting incorporated in my filtration system. It functions effectively as a stand alone unit insofar as keeping my contamination rates in acceptable ranges. If however, if I were to incorporate ducting, given my need, it would have to be at the intake. There’s no secondary diffuser with my filter, but this is essentially a design feature. The pleating is 12” thick and between each of the pleats are thin pieces of corrugated metal. These help defuse the air in such a way as to reduces turbulence. But there are other factors to consider for reducing turbulence. A volumetrically sufficient space behind the filter which allows enough pressure to build within the plenum is also needed so the air can pass through at a consistent rate over the entire surface of the filter medium. With a filter like mine we’re talking about somewhere in the neighborhood of 120 square feet of surface area. But my needs are kind of the opposite of yours. With sanding you are looking to pull airborne particulates away from you’re workzone, whereas my work necessitates pushing filtered air over my work. What I think might be effective for your purposes would be creating a hood that provides adequate space for you to work while minimizing the influx of the non/less-dusty ambient air from above, below, and to either side of you work space as it migrates toward the intake of your fan. The size of your hood could be maximized by approximately matching it to the flow rate of your exhaust fan. You could do that through experimentation, or by looking at your fan specs. If you’re fan is moving a lot of air, and I suspect it probably is, your hood could be pretty a pretty comfortable working size. Not that you would do this, but imagine if your sanding area was completely enclosed save for a panel with openings large enough only to permit you to put your hands in. It would kind of be like sticking your hands into and working within of a big vacuum cleaner. The airflow would reach pretty high velocities at the arm holes. Such a negative pressure environment would virtually guarantee all the dust was directed through your exhaust fan-or at the very least remain within your negative pressure cabinet. The challenge to designing a hood, of course, would be making something modular so it could be used with your sanders, miter saws, etc. Another design consideration is accommodating large pieces of lumber when you aren’t exclusively working with pieces of that fit on your workbench. I’m sure you could come up with something! I would suggest looking into fume hood designs and replicating those concepts at a scale useful to your needs.