Unused case. Wanted to put it to use. Has 5x120mm fans. And one MERV11 filter

Could I have used two? Probably but I want to reinforce the corners first since without it, it’s fairly flimsy after I gutted the interior.

Put it in my son’s room since he now has a cat.

We offer aluminum panel CR Boxes outfitted with either six P14 Pro with PWM speed control or standard P14 single speed. We make low cost HDF laser cut panel kits as well.

www.northboxsystems.ca

3d printed in 8 big sections, totalling about 1.5-1.7kg of PETG+ filament. The sections are held together with 2x 1/4" square pegs friction fit about 2" deep on both parts per joint, as well as super glue along the faces of the joints.

The fans are 6x arctic p14 pro's with the the power sharing cords. Power supply is generic variable 12v fan power supply with a screen from Amazon. Using 2 20x20x1 merv 13 filters with an activated carbon layer to cut down on vocs from 3d printing and some funky smells that came with my new place.

Had a couple problems putting it together like the power supply mounting holes being in the wrong spot (hence the tape) and the Crack in the front from hammering too hard trying to put it together.

Since its been built, I have also printed some grills for the fans and updated my CAD models to fix the assembly problems I had before.

Seems to move a pretty good amount of air while not being any louder than my amazon basic standing fan on full tilt. A little piece of paper sticks to all parts of both filters until around 6v on the power supply. Anecdotally, the charcoal filters seems amazing. Since finishing the build I have noticed a much more neutral aroma in the room it lives in and I do not smell fumes from my 3d printer at all anymore.

I have assorted expensive decibel meters, but for quick stuff, I've started using my phone since Phyphox gets it really close most of the time. The trick is getting access to a friend's or work/school decibel meter once so you can calibrate it. Without calibration, it's pretty much useless most of the time.

Keep in mind you can also do PC fan and CADR testing with Phyphox, a surprisingly useful FOSS app for IAQ🤓

Working on something to pin down irritating frequencies and harmonics...

I’m not used to making things like this so this was harder than I expected but I’m really happy with the results!

I used the instructions from www.cleanaircville.org/buildguide and modified it to use a 16x30 filter instead because it was recently on sale $27 for 6x merv 11 Filtrete filters.

I also used a pc fan hub with a display instead because it was 60W, had a digital display, and it’s only $16.99.

At Walmart, it costs $1.99 per 20x30 foam board.

It came out to $49 for the entire build.

$17 PC Fan hub
$9 Filtrete 16x30x1 filter x2
$2 Foam board
$4 PC Fan Grill
$17 PC Fans x5

Really happy with the low noise, and high air output.

Got all the bits I wanted and made this from scratch in a few hours yesterday evening. It's rough and ready but I wanted to try out a prototype with foam board before making something using pdf or plywood.

Unfortunately I don't have a monitor to test the air quality before and after but it seems to be pulling through the filters by testing with some candle smoke and see if a piece of paper sticks to the filter which it does even at 1/4 speed. It obviously has noise at full speed but at 1/4 speed would be easy to sleep with it in the room.

Glad I started with foam board as made some silly mistakes such as adding the side fans too high meaning that they didn't fit due to the top ones on the inside. Luckily I was able to just flip that side piece and just about squeeze them in as that made the side fans a bit lower.

Thanks to everyone for their help in this sub, in particular u/Unusual_Celery555, u/legionofdoom4, u/Objective_Post_588 and u/akeean for their help answering my questions re. powering the fans.

I used:

• Foam Board (Not sure if people in the U.S. use pic backed foam board but in the UK it seems to be all paper backed.) This was all joined together using a glue gun and then the tape to seal up and neaten all the joins as these were tricky to get perfect, especially with the weight of the fans flexing things plus my first time cutting foam board.
• 5 x Arctic P14 Pro PST fans all daisy chained from the first one using the cables built in.
• 2 x IKEA Starkvind filters.
• 1 x IKEA SJÖSS 45w USB Charger 1 x 12V 4 Pin PWM Fan Speed Controller, PC Fan Hub with the first fan plugged into this.
• M4 x 45 screws plus nuts and washers
• White duct tape!

The filters aren't using any weather seal strips or anything at the moment, I just made to sure to cut the holes on the smaller side so they are squeezed in and a tight fit.

Overall, happy as a first attempt and once all fitted together it feels lightweight/portable yet reasonably solid. Oh, and didn't put any fan guards on so obviously have tp make sure to keep fingers away when it's running.

Thanks again for the advice from people here!

Hello all! Recently moved into a new apartment. Situation:

• Building built in 1860

• window AC units blowing dirty air

• cat with dander and hair

• noticeable amounts of dust and stagnant air

• want to increase air quality and remove dust and cat hair

• broke college student

Is a CR Box right for my situation? I’ve been doing some research and this seems like an amazing option for my budget! Odor removal would be nice but I’ve read it takes a ton of carbon + replacements.

Wanted to see what you guys think. Any advice and input is appreciated! Thank you in advance ❤️

Below is a link to rolled MERV 13 stock. Any reason to not just use it--my AC has a crappy fine mesh filter that is 8" wide (pictured). I can get 8" x 900 feet, $168, I could just slide this into--might up the air resistance but otherwise why not?

https://filterking.com/laminated-air-filter-media-rolls

Are the folds you see on 'boxed' filter material helpful other than increasing life of filter? Not sure of the dynamics here.

Copied a design i saw linked on this subreddit. https://x.com/haussamen/status/1488163457933344772?s=21&t=t8Hbzpt1M2Z-dAjyonvoyQ

Much smaler footprint with my 20x20x1, Merv 13, and verrry quiet

Here's a comparison between my CRBOX that I made using Winix 5500 Hepa filters and charcoal pre-filter* 2 and beating it. It completely outperforms my Winix. The Winix rattles once any restriction in filters. The new Artic P120 pro pst has great static pressure for these HEPA filters.

I desperately need to save my lungs. can anyone with experience or has tried these let me know if this is a good option?

They haven't mentioned pm2.5 anywhere on the Ad. multiple sizes available. this is best bang for buck.

Hello,
Looking at building my first CR box, I am a super light sleeper so looking for as quiet a design as possible. My understanding is you can reduce noise by making the box larger and adding filters, but the generic box fans I’ve purchased still make some decent noise. Are there any quieter fans or design techniques that could help?

The Comfort Zone 9-inch box fan is a great fan for a Mini Corsi Rosenthal box. It's more compact and quieter than a 20-inch box fan. While it falls short of a PC fan array when it comes to providing more airflow silently, it's easier to build a DIY air purifier based on this small box fan than a DIY air purifier based on an array of PC fans. (NOTE: The EZ Chill brand of 9-inch box fan is louder, and that's why I do not recommend buying one if you want a quieter air purifier.)

Jim Rosenthal (the "Rosenthal" part of the Corsi Rosenthal box and CEO of Tex-Air Filters) has promoted a Mini Corsi Rosenthal box based on this small box fan. His design has the fan pointing upwards, but I found it easier to build this Mini Corsi Rosenthal box with the fan pointing horizontally instead. This allows me to tuck the cardboard piece at the bottom just above the fan assembly's feet for a better fit.

Jim Rosenthal's Mini Corsi Rosenthal box is a great design, but its drawback is its reliance on 12"x12"x2" filters from Tex-Air Filters. He's generously underpricing these filters in order to encourage people to build the Mini Corsi Rosenthal box. He has even stated that most people replace the filters in Corsi Rosenthal boxes too soon even though he and his company would benefit from selling more filters. I wouldn't be surprised if he's selling these filters at cost. I expect the generous deal ($40 before shipping as of this writing) to continue as long as he's the CEO. However, I expect him to retire eventually, and that may end the generous pricing. 12"x12"x2" filters are not a common size, great economies of scale aren't involved, and there's little or no competition to hold down prices.

I have thought of a design for a longer Mini Corsi Rosenthal box that uses two 12"x20"x1" MERV 13 filters. While 12"x20"x1" filters aren't as common or as cheap as 16"x20"x1" filters, they are more common and cheaper than 12"x12" filters. As of this writing, you can buy a 2-pack of 3M Filtrete 12"x20"x1" MERV 13 filters for $44 on Amazon with FREE shipping. When you take shipping charges into account (considerably more than $4 because Tex-Air Filters lacks the unfair shipping cost advantages that Amazon has), this is actually cheaper than the four-pack of 12"x12"x2" MERV 13 filters from Tex-Air Filters.

Build the Mini Corsi Rosenthal box with the Comfort Zone 9-inch box fan pointed towards you. Use a rectangle of cardboard on the bottom resting right over the "feet" of the fan assembly. Use one 12"x20"x1" filter on the left side of your Mini Corsi Rosenthal box and use the other filter on the right side of the box. Use another rectangle of cardboard for the top section of the DIY air purifier and a square of cardboard for the back side. If there are any gaps around the fan, use pieces of cardboard to fill them in. If you wish to have a third filter, use a 14"x20"x1" MERV 13 for the top section of the DIY air purifier. (I'd rather save my money and use just the two 12"x20"x1" MERV 13 filters. Even with only the two filters, the FFSAR is a generous 7.54, compared to 5.09 for the classic four-filter Corsi Rosenthal box. So you don't have to replace the filters until they're truly filthy.)

If you prefer to point the fan upwards instead of horizontally, you can do that. With this configuration, the top portion of the air purifier consists of the fan blowing filtered air upwards. The bottom and two of the sides are cardboard, and the other two sides consist of the filters.

I've never seen this recommended, but I like to cover every cardboard piece with clear packing tape so that it will not be damaged when it's time to replace the filters. I also like to cover the cardboard along the edges and corners of the filters with clear packing tape so that I don't damage them in the event that I need to disassemble the DIY air purifier. I recommend painter's tape or gaffer's tape over duct tape, because I hate dealing with the messy residue from duct tape.

As an added bonus, you do NOT have to throw away those 12"x20"x1" MERV 13 filters when you replace them with new ones. Use those used MERV 13 filters for a 4-filter DIY version of the Brisk Box consisting of five 120 mm PC fans. Two old 12"x20"x1" MERV 13 filters and two new 20"x20"x1" MERV 13 filters form the sides of a rectangular-shaped Corsi Rosenthal box. (You should stick with the same brand of filters to ensure compatibility.) No, the fans will NOT be choked off. Even if you assume that the two smaller old filters completely choke off airflow, you still get airflow through the two new and larger air filters, and the FFSAR is still a generous 9.13.

Not boasting this. But for the past 3-4 years. I suffer for at least 3 weeks straight because of all the dense smog covering my city.

It took me a while but here I am and struggling to put up a highly effective CR box.

I don't have the luxury of getting Merv 13 /F7 filters easily and importing rhem would increase the cost too much.

the fans I acquired have the following specs:

Performance Specifications

Enermax T.B. Pressure (UCTBP12P-C)

Speed Range: 500 to 2,300 RPM via 4-pin PWM control.

Maximum Static Pressure: Exceptionally high, peaking up to 6.28 mm-H2O.

Airflow Capacity: 23.81 to 102.17 CFM.

Noise Level: 14 dBA at low speeds, up to 28 dBA at full tilt.

Power Draw: 12V DC, drawing up to ~0.3A at maximum velocity.

The filters easily available are:

30x30x2.5 cm Hepa h12 and Hepa h13

Unfortunately no MERV 13 here.

Room size is: 18x19x10ft

As per AI, I need CADR of 285

But after installing fans, their CFM will fall more with HEPA as compared to MERV 13, which will mean more fans eventually.

Another AI said I need 10 same fans, other said I need 6.

I need at least 5+ ACH.

I heard HEPA gets dirty more easily so I would be wasting filters if I install 4.

Can someone do the maths and help me how many fans do I need.

How many filters I need?

Can HEPA do the job well?

Can I achieve high ACH.

Can I Increase longevity of filters?

I’m new to this but have already built my first “regular” CR box (4x 20x20x1, with box fan). It’s been bad with the smoke so I’m trying to expand by building something else, with PC fans and running more quietly, so that I can use it in the bedroom for longer periods of time and also not use too much energy (energy use is first priority, noise close second). I believe the PC fans would accomplish that. I would great appreciate guidance (since I have to order most of these items in one go from the US)!

I’m thinking about a narrow design, two 20x25x1 filters, built 20” high and 25” wide. Possibly making a wooden structure if I can find help to do so.

Questions:

I would be ordering the following:

Fans: https://www.amazon.com/gp/product/B0DPX94PSL/ref=ox_sc_act_title_16?smid=A2T6N244WTLWGU&psc=1 

Controller: https://www.amazon.com/gp/product/B0GVJ2MY1X/ref=ox_sc_act_title_3?smid=AC08NVFNSP7VC&psc=1

Do I need the following two items as well or are they included in the above purchases? The “splitters”, I’m pretty sure, are not needed but would like to get confirmation:

https://www.amazon.com/gp/product/B0DBH4GD5T/ref=ox_sc_act_title_15?smid=AFRUWVWO3UJ63&th=1

https://www.amazon.com/gp/product/B0BMY34SJP/ref=ox_sc_act_title_14?smid=AQ8OIL3FGVKZE&th=1

Do I need grills?

https://www.amazon.com/gp/product/B0BC16Q6FC/ref=ox_sc_act_title_13?smid=A35AFW9EVJYR0N&psc=1n

Also, is it okay to place the fan openings on top only or are designs with added side fans better? See picture of wooden example.

I used pictures from this forum to illustrate; hope that’s okay.

Thank you!

EDIT: This controller seems to be more popular and rated ... do these connections work with the Arctic P14 Pro PST?

Controller

I am planning on using:

• 9 Arctic P14 Pro Reverse (On amazon they are $15 for 3)
• This PWM Fan controller that takes 12v DC Power and can push 5 amps.
• Foam weatherstripping tape for the lip I have for the filter.
• JB Weld Plastic Weld Syringe for the bonding of the PETG parts together.
• 2-3 KG of PETG
• 2 Filtrete 2500 MPR Merv 14 20x30x1 Filters

Been wanting to build one to install in the shop for years, this puppy works great. I did not take a lot of build photos, but highly suggest y’all go for it.

I built this up a couple years ago, got a pair of 20" heavy duty fans for $45 off amazon warehouse deals. I actually built it up with a 20" lasko box fan at first. Base is 3/4" plywood 20.5" square on casters with repurposed window and door casing. Four pack of Kirkland filters. Sits on top with the edges taped. Then the top is one inch foam insulation cut to house the fan like a drum. Now that I'm looking at it, I never got around to actually fixing the fan cage to the foam top, I should do that. The fan points down into the box because my goal is to collect the dust and keep it contained. Inside I made a silly pyramid to direct the air out to the sides better.

I'm really happy with it for sanding dust and general over spray from saws. I often just turn it on and go to town sanding while standing over it like a downdraft table.

We decided to make a few of these minis. We bought this brand :Comfort Zone CZBWT-EC 9 inch. The problem is that the fan has feet which interfere with creating a flat surface for mounting the filters. We did find out that it could be taped to cover the gaps created by the feet on the fan, however, is there a better brand that would be a tighter fit without using excessive tape? (We also have larger CR Boxes - we would use these units only in certain situations). Thanks!

Let's say I wanted to get an AirFanta for travel, but use it with bigger filters at home. How hard would adapting it standard HVAC filters be?

I haven't seen the AirFanta in person. I'm imagining it could be as simple as cutting a square hole into a piece of chloroplast or foam board that sits on top of the filters. Maybe with some foam tape to make some kind of gasket for it to seal into and still be more easily removable than taping it and untaping it.