Air Filter Kit - Model-B/C - Design and Assembly 

We live in New Jersey and the smoke from the wild fires in Canada was really bad. Our 3 filters with the dowels for legs and 5 sides worked perfectly. Thanks again for your hard work!

The Model-A kit video will be out tomorrow! I ended up having to take a dog to the Pet Hospital and a Human to the Human Hospital Yesterday and am a bit behind on things. You can buy these kits here... www.etsy.com/listing/1373712349

3rd Gen kits are out now! Watch the video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-eYOvnqoW4H0.html Buy the kits www.etsy.com/listing/1687802690

Small world, I lived in Ferguson, MO for about 17 years. One of my favorite breweries is across the street from Soulcraft. Love your videos thanks.

Nice design but I suggest enlarging the inlet from a circle to a square as large as possible and providing a shroud for the outlet. In the current configuration there will be substantial backflow in the corners of the fan outlet side, which is preferentially drawn in and then blown out the front, reducing the flow through the filters. The circular restriction on the inlet further increases the pressure resistance on the inlet side. You can confirm this with visual observation of thin tissue paper. I've tested the impact of the shroud sizing and location using a calibrated flow capture hood, and two papers have been published showing the improvement of the Clean Air Delivery Rate for CR boxes with a shroud on outlet using smoke and NaCl aerosols.

Model B for the win! Nicely done.

I'd be curious to see a box fan comparison: cfm vs cfm with filters and decibels Thanks for such detailed videos with great flow

I’d also suggest using tape along any gaps, it makes a world of difference in performance especially when the filters start getting dirty. These can also be made using old computer fans if you need one that’s a bit more portable, I have 2 pc fan based ones with high static pressure that work wonders and can be made using any old pc and a cheap hepa filter or even paper towel as the filter medium

Great design, love how simply you have accounted for differences in filter dimensions between brands. Not sealing filters perfectly will lower performance a bit, not so critical with ultra low resistance filters like Filtrete MPR or 2" merv13. Be nice to have an option for caster wheels. I've been experimenting with aesthetic prefilter covers and found IKEA Teresia voile curtain material a good free flowing option that can be customised with permanent marker pens. Eg a Minecraft TNT themed cover. Look forward to 3d printable parts release to try and make a frame in UK.

We made 3 of the these from your original design. Love them and so happy you made these new versions. My question is are you making a design that has a filter on the bottom side? I like the design with it up from the floor by about 2 feet in my shop and a 5th side as the filter.

great design

Ha, yes this is a much better solution as to build it self, because the most people do not have the right tools at home to create the plates in such a nice matching way. This building would need several days and at the end it would not be so good. You have created here now an IKEA-like Filterbox. 😀

Can you build one that’s uses a carbon filter like the one on the iq air ?

I would like to see a particle test comparing a fully taped/sealed fan of this design vs the exact way this one is designed. Where the Velcro is with the fan sitting on top doesn't this Also allow "dirty" air to pass through? Also I thought the four corners on the top not being covered would pull in "dirty" air? Or after a specific run time as it purifies the air would this small gap even matter..

Incredible job, I have missed your progress... I have been running the Four filter Corsi box using Merv 11 3M filters now for a couple of months... Works really well with low noise using a Honeywell HF-910 it's been fantastic.. less noise then lasko... But it's a bit too large for my small room... I am trying to figure out how to make one with a single 4" filter for the smaller footprint size.

Awesome DIY stuff. I am very interested in buying one of your fan boxes. I am wondering if I can put one of these near the air ducts in our apartment. Would it absorb the pollution coming fromthe vents? Our apt is 1,200 sqft and even though our ac unit is sepparated, we get also a log of smells from.neighbors.

I'm debating between Model B/C. Which would you recommend for an 1800 sqft house?

one flaw if it is that These fan is considered a bit loud. I guess it would be ideal in big work shop.

I'm a bit late to the party, but have a question. Can your design be modified to include a 5th filter on the bottom?

Sorry, I could not find a link to buy a kit. Your Etsy page is showing completely different things.

Why don't you add another piece of wood inside as a shelf to hold the fan so it can sit below the site line? If it stays flush or lower, you don't see the ugly fan. Then, you can put a filter on the top which should also stay flush. The handle for the fan should be removed.

This design has been in use for decades. Corsi-Rosenthal, the two nutty-professors from UC Davis, had nothing to do with it. It's like someone claiming to have invented putting a rubberband around a deck of cards.

Awesome design! Can’t wait for the 3D printed one. Do you have a basic single 4” clip for a 20” fan, yet?

What is the adavantage of using a 3m one inch thick vs 2 inch thick..TIA

Finally built my 3M MERV 13 20x30 w/ air king last night. 1200 CFM you say? So that means virtually no loss in CFM, compared to running the Air King w/ no filters? 🤔 Amazing‼️😁👍🏽🛠️ Btw, the gaffers tape is the best masking tape I ever used. 6 months is the expected filter life? Thought it might last longer, since it’s 4 of them. Will this remove TVOC, HCHO or any gases? Are TVOC readings & particle readings measuring the same thing? Sorry if I asked this before, this is so foreign😢 to me. I noticed on the pkg, it does not filter ultra fine particles. Thanks !

Just made one but with fan pointing down inside. What's the difference if the fan blows inwards or outwards?

Love your videos! I'm just to order my filters to make my own. How long do the filters last before they need to change?

Can it filler, filler the smell of cigarettes and other smoking products I smoke neighbor complain about the smell

When will they be back in stock?

I've seen different designs and am not too sure of the pro's and con's in regards to fan direction. Wouldn't it be better to flip the fan so that the dust inlet becomes the fan side and not the filter side? Won't this increase inlet strength? If anyone knows the pro's and con's of this idea, please let me know.

Have you done any real world testing on how long the filters last in a normal home environment for air purification? Most of the filters recommend around a three month life but real world with the particle counter what are you seeing for the lifespan of filters? On the 4 filter design merv 14 changing every three months you could be $200+/yr on filter replacement alone. . Also the link to kits was not working..

I'm so glad you've done this when my little setup is done in 3 months I will make sure to purchase one of the kits. The company I purchased filters through sent me the wrong filter size 3 times... So I have a bunch of free filters that wouldn't fit any of your designs. I will say the Rosenthal design is pretty freaking amazing. I have a kid with asthma and we live off of a well-traveled street. Ever since I've implemented it after watching your videos everyone has noticed much better general health.

I'm interested in purchasing one of these kits. I love the idea that I would not be beholden to a particular manufacturer for filter or fan replacement. The only piece of information holding me back from pulling the trigger on it right now is that I want to make sure that the setup is quiet enough for home use. As far as I understand modern box fans should be producing no more than 55-60dbs but when researching the Hurricane box fan (one specifically recommended from a blog as a relatively quiet and high CFM fan) on the highest setting it's producing 70db according to one of the top Amazon video reviews. I understand this was designed for a shop environment but would greatly appreciate some of your thoughts on how the sound produced from the unit figures into the equation. It might sound like an unwarranted concern but the more I read about some of the effects of persistent exposure to high levels of noise the more it seems like a worthwhile pursuit to mitigate it as much as possible in the places we spend the majority of our time: www.sciencedirect.com/science/article/pii/S0047272722001505#:~:text=Increasing%20background%20noise%20by%204.1,noise%20pollution%20beyond%20health%20impacts My concern is that it may be a no free lunch situation where in order to reduce the noise while maintaining the necessary cfm we would have to get a bigger fan and run it at a lower rpm. As far as how quiet, quieter is obviously better and the EPA does mention anything above 45db as disruptive in a home environment. I understand this may not be obtainable and am generally willing to trade some higher background noise for cleaner air but there is probably a cutoff for when marginally cleaner air isn't worth the additional noise pollution. I know that these units were designed for shop use and think you have hit the nail on the head for value in that space. Hope what I've said is coherent and ends with you either recommending a quiet fan that works with this configuration or prototyping and releasing an a design specifically tailored for home use.

Would like to get the the kit! Are you still giving discounts/coupons?

But wont this blow the dust everywhere?

How much for the model c kit?

4:30 I think the gaps really don't Matter, I am planning to use door insulations to reduce air from coming somewhere through. Dude, this is content is RARE. In Germany = No of these vids. I guess because we don't have hvac systems (because of thick walls that hold Temperature, just da different architectual concept). It is reeeaaally hard to find cheap a d large HEPA Filters - I can only find expensive replacement Filters for systems that are a total rip-off. (There is no merv in Germany) If anyone can help - let me know.

I was actually thinking of building one but this price is really good you would spend only a little less doing it yourself

Still waiting for the new video. It's been over a year.

Attaching a flexible dryer duct or two to an outside source would add filtered ventilation. Then windows could be closed to create an allergy-free residential "clean room in terms air quality.

Box fans are not common in the UK. The ones we have widely available have a circular cage around the blades and an open frame structure.

The air quality detector link appears to be missing. Thanks for doing these tests

This is ingenious. Bravo, good sir! I'm a machinist in an aerospace CNC shop, and this channel makes my OCD so happy. Very concise information with no BS. Clean video work and balanced audio. Keep it up! Edit: The etsy link says it's unavailable.

Ordered 2!!!

Nice design! Upgrade suggestions. Possibly adding support tabs along the filter edges. Obviously need depends on the rigidity of the filter used. Also, thumbscrews would make filter changes easier, as well.

Think it would be safe to stick a led bulb in them? Could also function as a soft light lamp...

Dude - you've got your hands full making these insanely detailed videos, then all the work to make, package and ship your orders, all after your family commitments and you still respond to every comment on your videos. That is pretty insane and you have my respect (and subscription)! I'll be looking to make one of these myself but with a drum fan instead of the lower-powered box fans. Much thanks!