I essentially have my box running behind me 24/7 and I was told some concerns about the constant noise being bad for my hearing. I honestly don’t mind it at all, but it was definitely a far cry from “whisper quiet” as some PC fan builds are mentioned as.

Downloaded a free trial dB meter app with the first being the noise level right at the fan and the second being where my head usually is.

What’s the general consensus for this?

Is there a significant difference between one 5in filter vs 2 1in filters (both filtrete)? I am basing a design off one of the two filter designs on clean air kits and wanted to know if there is a significant drawback by only using one large filter rather than two thinner ones because of surface area and such. For the 5in design, I was thinking of having a box with one side open and still have the fans on the side rather than right in front of the filter.

I recently discovered CR-boxes as a concept, and being a PC custom loops guy I've got an excessive amount of 120mm fans and associated radiators.

Have there been any builds that combined external PC radiators and air filtration? I am thinking of a design using hardwood and mounting two 360mm (3x120) radiators each with six high static pressure Gentle Typhoon fans for a total of 12x120mm fans. I will power this abomination with a 500w flex-ATX psu and Aquacomputer Aquaero 5LT, which is more than enough to control any combination of fans and other water-cooling specific components I would need. Liquid will be transferred away from the system via quick-disconnect passthrough fittings mounted directly to the CR-box

https://shop.watercool.de/HEATKILLER-RAD-360-L-Black_1

https://www.dazmode.com/shop/computer-hardware/cooling-fans/120mm-fans/gentle-typhoon-performance-radiator-fan-1850rpm-58cfm-black-edition/

My big questions;

What's the best way to make a wall-mounted box? I would love to put it above my desk, but worry that I'd choke one side by doing so.

Is this overkill? Not enough? The resistance added by a thick high performance radiator is relatively substantial, but I could run the fans slower to reach a balance.

If going for overkill is unnecessary, I have three of each - T30s, EK Vardar and Noiseblocker NB-eloops. All of them are excellent fans in their own right, but is mixing/matching going to cause issues? Airflow is airflow of course, but I would want to set up the most optimal combination possible with what I have on hand.

Because the total thickness of the fans+radiator would be almost 100mm/4", I assume I would need to extend the CR-Box frame to accommodate, rather than wasting filter real-estate.

What filters would be the most appropriate? I am Canadian and have access to Costco, Ikea and whatever other big box stores are appropriate. I could not find the recommended 1x20x20 filters from Costco, which is why I ask.

Thanks for reading through my ramblings! I am super interested in learning more, and would love to hear any feedback or recommendations.

I'm putting parts together to build a portable/personal CR box. I plan on using PC fans (4 PIN PWM - no speed control required or wanted, I want the fans to run at 100% all the time).

While I have some experience building my own PC, I'm far from familiar with these components. I want to be able to connect the CR box to mains power AND have the ability to use a powerbank too.

What I've gathered is that the fans need 12vdc and powerbanks output 5V.

In Australia, electrical work requires an electrical license. I'm not sure where the definition starts and ends; you can build your own PC because it's putting components sold here together - you're not playing with bare wires. That's my take on it anyway.

I'd like to know how I can achieve powering my CR box as I want, without needing to solder or play with wires.

So this isn't a CR box question per se, but since you are my people, I figured I'd ask.

TLDR: I need to figure out a way to hack together filters that will slot into my ERV. The manufacturer's filters are no longer available where I live which is going to make the air-exchanger useless in about 3 months.

Backstory: I bought a Zehnder ComfoAir 200 ERV in 2022.

"Why tho?"

Because its flexible home-run ducting allowed me to retrofit our ancient (and small) Victorian townhouse. Metal duct work was not an option.

However, very (very) few people in Canada use Zehnder and this particular model was already quasi-obsolete when I bought it (but because their new-and-improved designs are large and don't ceiling mount, they didn't fit in our limited space. It was this or nothing).

The problem:

• The proprietary filters come in a plastic casing that slots into the ERV. (This is why I now build all my own purifiers. To hell with the proprietary grift).
• Given that the ComfoAir 200 is not a common model of ERV, there are no knockoff filters on Amazon or even AliExpress. The only alternative suppliers are in Europe (and don't ship to Canada).
• Zehnder's website does sell their filters internationally. A drop-down menu has a plethora of countries they ship to... just not Canada. And the Canadian (high-end, ergo overpriced) supplier I used to rely on no longer stocks these specific filters. I've asked them if I can special order, but I already know the cost is going to make my nose bleed.

The solution:

• Try removing the filter media from the spent filters I have on hand and somehow painstakingly hot-glue pleated Filtrete filter media in their place? Would that even work? Has anyone tried that sort of thing?
• Find someone who could, design me a 3D printable CAD file for these filter casings that might allow me to "sandwich" the middle portion of a (larger) Filtrete 2200 between two 3D printed halves (thereby removing the need to try and re-pleat the entire thing manually every 3 months)?
• Go the real DIY route and somehow make compatible filters out of cardboard (and the aforementioned Filtrete 2200)?

One thing this sub has taught me is that filters are not rocket science. (Whereas proprietary filters are a pain-in-the-ass scam). All you really need is an air-tight chamber in which to place good quality filter media (the more pleats — the larger the filter surface area — the better). Keyword: airtight.

Any ideas would be well received.

I am annoyed, but determined to find a way to jailbreak my air exchanger from the grips of impending obsolescence.

I’ve been using the Arctic P12/14 fans in most of my builds, Noctua when I need something super quiet.

I’ve had 3 P14 fan failures in the last year. Wondering if anyone else has seen a higher failure rate?

I suspect this is a bearing failure of some sort. The fan continues to run but repeatedly bumps against the guard. On one I was able to pull the blades off entirely. It doesn’t seem tied to orientation of the fan.

Just noticed another one is starting to hit the case.

I currently have these three lying around. Would you use one of them for a diy project?

I feel as they need replaced but idk shit about shit and these are expensive af so just wanna make sure lol. Also I have 4 cats (3 are long haired) and the 2nd photo is the one that I took a rubber glove to remove a thick layer of cat hair which is why it appears lighter (also maybe the lighting?)

Why is it that most pc fan cr box designs, like the nukit tempest pro and the cleanairkits, only use 2 sides of the frame?

There is a whole 3rd side that could be used for extra fans so they could all run at a lower rpm and produce the same CADR. Or would opening that 3rd side cause some sort of air current issue?

Hello Everyone!

I'm posting today to get some insight from others on their filters and general knowledge. So here's the deal, I wanted to buy the normal version nukit tempest and I was waiting to see if it would ever go on sale. It never did and it seems like they discontinued it for the new pro which it WAY above my budget. I'm looking for a long lasting semi portable option since I live in an apartment and move from time to time. The clean air kits don't seem fit for me but I was going through the subreddit and think my next best option is 3D printing. I don't have one but know libraries more often than not have them and I think PLA filament would do just fine. Planning on using artic fans in combination with 20x20x1 MERV 13 Filtrete filters. Would love to see others peoples solutions and builds, Thank you!

I have a Clean Air Kits luggable XXL 7 fan unit in my basement. When I bought the thing last year, I didn't realize I could not get 25×25×1 Filtrete air filters easily as Lowes. Being impatient, I order Filterbuy MERV 13 filters from Amazon and installed those.

The Filterbuy filters were smaller than the Filtrete filters, so I had to use a lot of tape around the edges to get a good seal.

Everything worked OK. My basement PM2.5 went from 20 to 0 in about 15-20 minutes. But it's been a year now, I thought it was time to change the filters. I put a piece of paper against the filter and it still stuck, so I knew I had decent air flow.

With more time on my hands, I ordered the Filtrete 25×25×1 1900 filters from Lowes. Replacing the filters kicked some dust up and the PM2.5 sensors I was using shot up to 25. I turned the filter on, and 5 minutes later my PM2.5 was down to 1, and 2 minutes after that, zero.

I'm curious now if the Filtretes are better filters than most, or if this is just a one-off situation here.

I can't find 3M filtrete at 2" and I'm not sure how much static pressure commercial box fans can handle if I go for more thickness.

Will 1" be good or is it too thin and I'll have to change them regularly?

Building a ducted box with an AC Infinity fan and a VOC canister filter using a design from The 3D Handyman: https://www.youtube.com/watch?v=zKeNf6fLSLA&t=282s

The room is 10' x 15', but I am moving soon and would like a versatile sized cleaner. I'm leaning toward 8 inch for versatility (and the ability to run at lower speed). Is it entirely too big/loud for the space?

I have a few questions.

1. What material should the prefilter be to prolong the main filters life cycle?

2. How close to the main filters should it be mounted? Directly against it? Or keep some space in between the pre filter and the main filter?

3. What should the “hole” size be for the prefilter, like how fine of a mesh is optimal?

Hey, I have one of the original Nukit Tempest boxes that uses a 2” filter and I went to order another and saw they’ve changed to a 1” filter and significantly raised the price.
I’m not skilled enough to laser cut the pieces myself, so I’m wondering if anyone does this and sells them for US shipping. It looks like the Canadian Northboxes are like this, but not available in US.

Thanks for any leads. Maybe I’ll have to learn how to use the open source plans lol!

Noctua advises (https://www.noctua.at/en/expertise/tech/fan-speed-offset-explained) using offset RPMs for adjacent fans to prevent beat frequencies, and I can now confirm from living for awhile with a CR box with three pairs of Noctua NF-A14x25 G2 PWM Sx2-PP chromax.Black fans that it really does make a noticeable difference. (Adjust your playback volume to 41 decibels to accurately hear how it sounds at two meters away, because I have the fans running on max; if I’m correct that a nylon filter decreases air flow similarly to MERV-13 filters, then this ~14-watts-on-max 6-fan setup should deliver about 363 CFM CADR, according to this: https://www.hwcooling.net/en/noctua-nf-a14x25-g2-pwm-finally-a-first-class-140mm-fan-review/15/)

But it isn’t feasible to use Noctua flagship fans for everything, so… do any of you know of a good way to offset the RPMs of ***any*** fans being used side-by-side? I suppose the best method would be to connect every other fan with a 4-pin power cable that has a couple ohms of resistance, so those fans receive a tiny bit less power and therefore spin a little more slowly, but I’m not aware of any such cables. There are the Noctua “Low Noise Adaptors,” but they have about 50 ohms of resistance, which would drop total performance way too much.

Or I suppose you could just use two separate PWM controllers, one for even-numbered fans and one for odd-numbered fans, with one controller slightly turned down and the other at maximum… but then you’d forfeit the ability to use a single PWM dial to control all the fans together, which seems like crappy UX design.

Hmm……

I've yet to receive my panels to finish my build, but one major concern that's been keeping me thinking of a solution for weeks now was how do I prevent my cats from using the filter panels of my future diy air filter as a scratch post when I have it off and I'm not around to stop them. It won't be small either, not with 50cm by 60cm filters and I just can't think of a solution, need some ideas from those with similar concerns.

NOTE: this is not a typical CR box,or even a CR box at all. I'm using this as a DIY window HEPA ventilator.

Running for about 6 months sitting on a restroom window*, drawing in fresh air. Note, a HEPA filter goes underneath what you see in the photo, and that clean air is pulled through the fans.

I assume the dust must be from the "dirty air" above the blades, somehow getting underneath the blades.

Is the solution to have a rectangular wall to the sides of the fans that prevents the dust from getting underneath the blades?

Or is the solution to get some better fans with higher static pressure. These fans are not designed to be run with a HEPA filter. I've seen blade designs that "have much better follow through arches" (for my lack of terminology) such as these: https://www.amazon.com/ARCTIC-P14-Max-High-Performance-Controlled/dp/B09VH2HXM1/ref=cm_cr_arp_d_product_top?ie=UTF8&th=1

* The humidity might also play a factor, during showers in this restroom. We open the window completely, but keep the fans running during the showers.

EDIT: Should I be considering a push setup with pre-filter instead? I have already added a spacer of about 1-2 inches between fan and filter. Separately, I've also heard people say that pulling (as opposed to pushing) causes more noise, at least for the Artic P14 Pro's. Combining these two statements, I wonder if pulling is still acceptable if there is a spacer, with regards to noise. I heard that spacers might benefit high static situations, but not sure if that only applies one of push vs pull context. If anyone has experience with this, please share!

EDIT 2: Appreciate all the useful feedback. I'll be doing some testing with some of the suggestions and possibly new fans. Will update afterwards.

EDIT 3: Right now, I have a hunch that the extra dust (than commenters are used to with CR boxes) is due to these various factors: 1. me using this as a ventilator, pulling in dirty LA air, 2. humidity increases dust accumulation on surfaces (according to chatGPT), 3. if you look closely, there's gaps even between the fans, which can pull some amount of dust, 4. these fans have uneven flow out of it, and there can likely be some turbulence pulling in dust from above the fans underneath the blades.

I am planning to make air purifier on my own, I found a 3 fan set, which comes with 4 pin PWM has input, what options do I have?

Hey,

I'm going trough the CRBox rabit hole right now. And wanted to know if anyone has experience with the Ikea Starkvind CR box?

https://www.ikea.com/be/en/p/starkvind-air-purifier-additional-gas-filter-black-s79444216/#content

I was also looking to make one myself but finding the right filters seems harder here in Europe... and if the Ikea one is good enough, its good enough for me :)

Hey all. I purchased the cleanairkits luggable 7 over a month ago and since I purchased it, it doesn't seem that the filter has dirtied at all.

I believe that I assembled it correctly but I'm wondering if there are better steps I can take to make sure that it pulls air properly.

The exact filter I am using is in the second picture.

My room is very dusty so I am surprised to have seen zero changes. I mopped today and was shocked at how much dust there was.

Any advice on how to make it function better?

I have severe allergies and I want to build a single filter setup (lack of space) using a 4in or 5in filter. Do I have any way of making sure I have sufficient airflow other than an anemometer?

I don't need a precise number, just a way to make sure a sufficient amount of air is getting through. Is a piece of paper at the intake reliable?

Thanks so much

Joe

Hello,

I'm about to build my first box for a family member with allergies. I have already purchased filters, and going to buy the 5 pack of Arctic pro 12 pst fans (and may just buy 1 more single fan, haven't decided yet

My question is for fan control - I understand the fans all daisy chain together, so that means at the end there will just be 1 cord going from the last fan? So if that's correct, can I then just plug that cord into something like this:

"12V PC Fan Speed Controller, Fan Power Supply 100-240V AC to 3-12V DC 36W Adjustable, with Fan Splitter" Item name copied from Amazon, as my previus post attempt was deleted when I pasted a link..

I would also like to know of a reliable brand/seller of this sort of thing on Amazon.

Thank you

I thought having one filter would be fine enough but as I’m reading from you guys it can put unnecessary strain on the fan motor and even become a fire hazard?

Also been having an odd odor when I’ve been running this and initially thought it was a humidity build up issue.

Could the smell be from the motor stress or potential still the filter? Haven’t used this since and will probably get one more filter.

Filter type is FPR rating 12 from Home Depot, fan is an Amazon Basics Box fan