The great thing about all these DIY designs is that we can build purifiers for all sorts of requirements. This design is perfect for the bedroom where you don't want to blow up a storm and you want things to be quiet, while the big and ugly box fan filter I have does an amazing job clearing out particles in my 1250sq/ft house as a whole house filter. All of these designs are a huge leap in cost savings and efficiency compared to any air purifiers on the market.
If you connect the fan to PV panels in a sunny window, you can get "free" air purification during daylight. Not sure if the cheap, small harborfreight panels will be sufficient.
Hi, at this time my efforts are focused on www.cleanairkits.com so I haven't taken the time to make those schematics available in the same way that these are. The Tower of Power featured on my twitter uses 10 Arctic P14 fans with 20"x30" Filtrete 1900 filters. If you would like to build one get some foam core and a drywall circle cutter as recommended here and measure out where to fit 5 140mm circles in a 30" long side. Use the DIY template from Arctic's website to find where to put the screw holes (linked on my github). Width of the panel needs to be at least 19mm (filter thickness) + 140mm (fan width) + 19mm (filter thickness). Then tape it up and wire it up.
Great video! But I'm curious how you determined CADR values- did you measure actual flow volumes and rates, use manometer measurements, or did you infer from fan specs and fudge the numbers to account for the filter restriction? As I understand, the Lasko fans suffer a significant drop in flow rate when factoring in the flow restriction from the filters. Thanks for sharing this information!
I've made a larger one with double the fans and only 120 mm (smaller fans are sometimes, typically, because they spin at higher RPMs) and it's barely audible. Nothing to be concerned about. ;)
Fans must SUCK air not blow it out. This is the major "wrong" with commercial filters, that they create a lot of turbulence. You would get same CADR, but much more effective filtering at the same time if fans blows in and nonturbulent air comes all around. Fast intake air will attract more dust, while this design you have only effectively work in very small empty rooms. Turbulence pushes air away and dusty air is rushed toward ceiling and walls and if not really smooth walls, dust will go everywhere that would never went if no filter would running. People think how filter cleaned air, but in fact dust was pushed into all corners, furniture, fabric, ...
I am having trouble with the power supply. Do I need to find a pwn to 12 volt ? The clean air kits has a barrel cable coming out of there fans which is confusing. It then connects to a female barrel to a usb c female then they use usb c to plug into the wall. Why dont they just skip all that hassle and go straight from pwn to usb c ? P.S I've also looked at your links in the description they are incomplete.
Looks nice, but I have no idea why it works, accordingly to Arctic, this fans produce static pressure of 2.2 mm H2O (why to use such a BS units?) which is about 22 Pa. While E10- 11 filters (which I assume IKEA sells) usually require about 150-200 Pa for operation at the beginning. Even if you divide it by 4, pressure still will be two times lower than designed. So 227 CFM *CADR* compared to 280 CFM, from datasheet at zero pressure drop, looks very optimistic. Though this design should work with G3 filters or similar.
🤔FWIW, Ikea's page says it uses an EPA12 filter (E12), but couldn't find info on the filter's pressure drop/minimal resistance to airflow. I'm not familiar with how/why PC Fans static pressure are able to push the air, but from other independent tests, it is apparent they work. H2O is not a "BS" unit, it is a standard measurement of low range air pressure
@@yeetusfetus8687 I've just noticed that I was wrong: static pressure mean that it still will be 22 Pa if you connect multiple fans in parallel, to get higher pressue one should connect it in series. It's like electrical batteries.
@@swgar also that's why he has that plate on top etc. if you can make a hard seal the pressure is going be lower inside
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The filters aren't great, but if somebody puts this on the market and with an esphome controller so I can integrate it easily into Home Assistant, folks will start throwing money at you, me first
One problem - those PC fans are designed to be quiet but they are also designed to be used in a relatively resistance free device. As the filters do their job and start to get a build up of particulates on them more power is needed to pull air through them. Those fans are not designed for that kind of power, they have small rather weak motors in them because a PC does not have a lot of resistance - no HEPA filters in a PC - therefore not a lot of resistance. As the filters accumulate build up those fan motors will encounter more resistance to air flow and they will definitely slow down and probably start to get warmer thereby reducing air flow and their lifespan.
Actually, moden PC fans (including the Artic P12/P14s) tend to balance airflow and static pressure (unless specified for airflow, and even then the Noctua flow ones still perform reasonably well in pressure situations...) and perform pretty well even up against a radiator, which similar cakes with dust and debris. This usage is well within their design spec.
isn't this really comparing apple to oranges? since Filtrete filters are much worse filters than those used in commercial purifieres on this list' ; so maybe you can compare cadr of pm2.5 efficiency but the results would not reproduce at pm1 or pm0.1 - thats means i suspect it would turn out these filtrete dont work; and the most dangerous particles are actually
Hi, filtrete do filter at 0.3. In fact, the MERV standard specifies a minimum filtration efficiency at 0.3. The filtrete exceed the minimum and also filter 0.1. The single pass efficiency at these sizes is lower than HEPA but in box fan CR box designs, this is compensated for by the higher flow rate. High flow * lower single pass efficiency = high cadr.
The great thing about all these DIY designs is that we can build purifiers for all sorts of requirements. This design is perfect for the bedroom where you don't want to blow up a storm and you want things to be quiet, while the big and ugly box fan filter I have does an amazing job clearing out particles in my 1250sq/ft house as a whole house filter. All of these designs are a huge leap in cost savings and efficiency compared to any air purifiers on the market.
This channel is seriously underrates. The video quality is impressive.
This is awesome! 😁 I'm definitely going to build this. I have built (4) Corsi-Rosenthal boxes for family.
Air Quality Experts you are my jam!
Thanks for a very nice guide :)
I'm contemplating making something similar, with some sort of cat guard on top - should I ever get one.
How did Corsi and Rosenthal get their names on this design? It is older than they are. It is just a quad filter.
If you connect the fan to PV panels in a sunny window, you can get "free" air purification during daylight. Not sure if the cheap, small harborfreight panels will be sufficient.
You sir, is a legend!
01:07 cool thing about the NIOSH SLM app, didn't know it was possible to subtract ambient noise!
You could try and use centrifugal radial blowers as they are very compact and have high static pressure
PC fans are also insanely lower in wattage than conventional air purifiers right?
Curious if you've tested the same setup with cheaper HVAC air filters to see if we can get away with saving some money on filters.
wish the powersupply came with fan speed controller
Has anyone though about making a 3D printable design like this?
Why not pc fans to replace window fans? since more efficient.
Can you please provide schematics for the Tower of Power?
Hi, at this time my efforts are focused on www.cleanairkits.com so I haven't taken the time to make those schematics available in the same way that these are.
The Tower of Power featured on my twitter uses 10 Arctic P14 fans with 20"x30" Filtrete 1900 filters. If you would like to build one get some foam core and a drywall circle cutter as recommended here and measure out where to fit 5 140mm circles in a 30" long side. Use the DIY template from Arctic's website to find where to put the screw holes (linked on my github). Width of the panel needs to be at least 19mm (filter thickness) + 140mm (fan width) + 19mm (filter thickness). Then tape it up and wire it up.
omg..you responded! Bless you! Can't thank you enough for this!
IKEA filters have no MERV rating. Would rather get the Nordic one. £61 for 6 MERV 14 filters.
The IKEA filters are HEPA however.
@@groundzero_-lm4md Are you sure? Don't think it's mentioned anywhere
Ikeas filters are HEPA rated
Great video! But I'm curious how you determined CADR values- did you measure actual flow volumes and rates, use manometer measurements, or did you infer from fan specs and fudge the numbers to account for the filter restriction? As I understand, the Lasko fans suffer a significant drop in flow rate when factoring in the flow restriction from the filters. Thanks for sharing this information!
CADR was measured with a particle decay experiment.
Question, why did you cut out the sound just as you plugged in the fans at the end?? Makes me wonder.
I've made a larger one with double the fans and only 120 mm (smaller fans are sometimes, typically, because they spin at higher RPMs) and it's barely audible. Nothing to be concerned about. ;)
@@emma70707 please post the video on the one with double the fans?
Fans must SUCK air not blow it out. This is the major "wrong" with commercial filters, that they create a lot of turbulence. You would get same CADR, but much more effective filtering at the same time if fans blows in and nonturbulent air comes all around. Fast intake air will attract more dust, while this design you have only effectively work in very small empty rooms. Turbulence pushes air away and dusty air is rushed toward ceiling and walls and if not really smooth walls, dust will go everywhere that would never went if no filter would running. People think how filter cleaned air, but in fact dust was pushed into all corners, furniture, fabric, ...
Are you saying it would be better if the fans were flipped the other way around?
Can’t you just use a lap cooling pad?
I am having trouble with the power supply. Do I need to find a pwn to 12 volt ? The clean air kits has a barrel cable coming out of there fans which is confusing. It then connects to a female barrel to a usb c female then they use usb c to plug into the wall. Why dont they just skip all that hassle and go straight from pwn to usb c ?
P.S I've also looked at your links in the description they are incomplete.
A good article to explain connector options is this one itsairborne.com/untangling-the-electronics-in-a-pc-fan-air-purifier-33f36b5834e1
@@robwissmann1756 Thank you.
Looks nice, but I have no idea why it works, accordingly to Arctic, this fans produce static pressure of 2.2 mm H2O (why to use such a BS units?) which is about 22 Pa. While E10- 11 filters (which I assume IKEA sells) usually require about 150-200 Pa for operation at the beginning. Even if you divide it by 4, pressure still will be two times lower than designed.
So 227 CFM *CADR* compared to 280 CFM, from datasheet at zero pressure drop, looks very optimistic.
Though this design should work with G3 filters or similar.
🤔FWIW, Ikea's page says it uses an EPA12 filter (E12), but couldn't find info on the filter's pressure drop/minimal resistance to airflow.
I'm not familiar with how/why PC Fans static pressure are able to push the air, but from other independent tests, it is apparent they work. H2O is not a "BS" unit, it is a standard measurement of low range air pressure
21.57 Pa per fan = 107.85 total
The 4 starkvind filters combined should also further reduce the pressure required to be overcome
@@yeetusfetus8687 I've just noticed that I was wrong: static pressure mean that it still will be 22 Pa if you connect multiple fans in parallel, to get higher pressue one should connect it in series. It's like electrical batteries.
@@swgar also that's why he has that plate on top etc. if you can make a hard seal the pressure is going be lower inside
The filters aren't great, but if somebody puts this on the market and with an esphome controller so I can integrate it easily into Home Assistant, folks will start throwing money at you, me first
One problem - those PC fans are designed to be quiet but they are also designed to be used in a relatively resistance free device. As the filters do their job and start to get a build up of particulates on them more power is needed to pull air through them. Those fans are not designed for that kind of power, they have small rather weak motors in them because a PC does not have a lot of resistance - no HEPA filters in a PC - therefore not a lot of resistance. As the filters accumulate build up those fan motors will encounter more resistance to air flow and they will definitely slow down and probably start to get warmer thereby reducing air flow and their lifespan.
Actually, moden PC fans (including the Artic P12/P14s) tend to balance airflow and static pressure (unless specified for airflow, and even then the Noctua flow ones still perform reasonably well in pressure situations...) and perform pretty well even up against a radiator, which similar cakes with dust and debris. This usage is well within their design spec.
P14 was designed specifically for static pressure.
y is it fookin blurry during the power connection part and doesn't how to do that step by step, like a draw the rest of the owl situation.
isn't this really comparing apple to oranges? since Filtrete filters are much worse filters than those used in commercial purifieres on this list' ; so maybe you can compare cadr of pm2.5 efficiency but the results would not reproduce at pm1 or pm0.1 - thats means i suspect it would turn out these filtrete dont work; and the most dangerous particles are actually
Hi, filtrete do filter at 0.3. In fact, the MERV standard specifies a minimum filtration efficiency at 0.3. The filtrete exceed the minimum and also filter 0.1. The single pass efficiency at these sizes is lower than HEPA but in box fan CR box designs, this is compensated for by the higher flow rate. High flow * lower single pass efficiency = high cadr.
I’ll add that we don’t have to rely on my results here to see that filtrete work for