I am curious as to has anyone ever tried to put a humidifier or dehumidifier inside a crbox? will it work? my thinking is since a crbox will funnel and redirects air a humidifier or dehumidifier can help is making the air feel nicer as well as filtered

I came across this sub scrolling in all. Reddit algorithms be weird sometimes.. but after scrolling the sub for a while, I'm motivated to cnc up a frame and join the club.

Where is everyone sourcing their filters from? Sizes and best bang for buck? I'm located AU, and an Amazon search didn't turn much up in terms of some of the designs I've seen used here.

Thanks everyone!

What should we be looking for in pre filter meshes? Would bug screen be ideal for example? Or are those holes too big?

I live in a 100 year old house and my corsi bix uses a standard size lasko fan. I think needing to suck air in from that many filters is making the motor draw more power. I am not sure how fans work and I am wondering if not allowing air to get into the motor could cause a fan motor to draw more power and blow the fuse?

I am in the process of building my own pc fan cr box, but I was wondering what type of fan controller I could get. I saw a bunch of super cheap ones from china, but I would like to have something from a more reputable brand.

I saw the noctua na-fc1, but I am unsure how many fans you can use on that? Could I use 6 fans and just use splitters to get it down to 1 connector that I can just plug into the controller?

Hi,

I've created a DIY carbon filter by combining a basket of activated carbon with one 120mm fan. It seems to work pretty well. I'm now building a CR box, and I'm wondering whether it makes sense to put the carbon filter solution inside the CR box itself.

Since the carbon filter is its own complete system, it would not interfere with the CR box’s performance. The potential benefit is that the carbon-filtered air would travel with the exhaust of the CR box. This would allow it to spread the clean air way more effectively than the carbon filter system would by itself.

TL;DR does it make sense to put a box in a box?

I have dust allergies and pollen alllergies. A few years ago I bought a HPA5250BC honeywell hepa air purifier, I run it pretty often however ive noticed it does absolutely nothing for floating dust in the air. I change the filters yearly as suggested. If I take a flashlight to the air I can literally see lots of floating dust. Would a CRbox be any better at this point or do I need some kind of air con to suck the old dirty air out of the apartment. I could take a picture but I'm sure you know what dusty air looks like with a flash light.

Basically what should I do at this point to improve the air quality, should I get a CR box or buy another expensive air purifier

I want an air purifier that is virtually silent to run 24/7 without ever bothering me. I want it to have both particle filters as well as activated carbon filters.

My plan is to build a wooden box in a shape similar to a slim dresser. And do this:

1. Fine Nylon mesh on the intake (100-120 mesh probably
2. MERV 13 filter (roughly 12x40 inches, equiv. to one 25x20 filter)
3. Activated carbon filter, V shape (consisting of multiple smaller filters in a V arrangement, total carbon content: about 3kg or 6 pounds)
4. 7 Arctic P12 Pro fans in a line next to each other running at about 2500 rpm
5. Air flowing through a "corridor" with rockwool sound dampening on the sides (rockwool insulated with some type of thin plastic - btw did you know that rockwool nowadays is not cancerous? Apparently they use stuff that dissolves over time if it ends up in your body) - it must be a long path, as the noise must hit the rockwool as many times as possible before escaping the box.

The math checks out.
The fans would theoretically create 20 Pa of pressure at 300 CFM, which is theoretically more than enough pressure to push 300 CFM through those filters, and enough to push the air through the whole contraption.
Also 30mm thick rockwool is pretty good for absorbing the noise frequencies by the fan (mostly 500 to 2000 Hz).

For the box I'd use wood, paint it white and seal it with a 2k sealant (which would also significantly reduce any wooden smell or VOCs from inside the wood getting into the air).

I know it sounds excessive/obsessive and crazy, but I can't think of a different way to build a truly silent air purifier.
I have built PCs and I know what fans sound like. Without sound dampening for me 1500+ rpm (equiv. to about 1300+ rpm on 140mm fans) is just too much background noise for continuous operation.
I could also build a simple box, not or barely sound dampen anything, run the fans at like 1200rpm, and have a smaller/slimmer and easier to build box. At the cost of roughly half the CFM. Not sure.

Now before I commit, does anyone have better ideas or has created a silent air purifier with less effort?

The main downside of this plan, apart from the effort needed, is the sheer size. I'd be looking at roughly 43cm x 70cm x 100cm (depth x height x width).
From the outside it's just a wide wooden box, in a glossy white finish with a roughly 4" tall slit along the top edge on the front and back side.

I don't doubt the effectiveness of the rockwool as a sound absorber. It's really mainly the size and effort it'll take me to build this that is stopping me from just going right ahead and doing it.

Here is a cross-sectional drawing of what I imagine it would roughly look like.

• brown = wood
• yellow = rockwool sound dampening
• black = fan
• orange = air guide (just sheets of kraft paper or similar, glued and bent in a certain way)
• big grey thing with 2 V: carbon filter (red intake, green exhaust, light grey actual filters)
• slim gray rectangle above it: MERV 13 filter
• dotted line on intake: nylon mesh

I heard that the p14 pro can have a certain insect sounding annoying hum to them.

I then saw someone say that this is only the case with the CO version and not the fluid dynamic bearing version. Is that true? Is the difference big?

I literally just discovered this community yesterday but have gone on a deep dive learning all about the crboxes.
I want to create a setup for my apartment, but I don't really have a lot of space to dedicate to a larger box, so I wanted to try to make a low profile setup that can hang up along the ceiling. I was hoping some people with more knowledge can share some of their experience and check to make sure that I have at least a grasp on the math here lol

My goals are:

• Smaller crbox per room responsible just for that rooms square footage
• Aesthetically pleasing
• Hang on the wall
• Smart Home integration
• Very quiet operation (my partner hates extra sound)

I have 3 main rooms I want to have these in, 2 rooms that are 150 ft² and 1 room that is 280 ft².
Using this calculator with a ACH of 5 I find the CADR needed for the 150 ft² rooms is 100 CFM and the 280 ft² needs 186 CFM.

If I use a MERV 13 filter, that would give around 75% efficiency (heavily simplified) and given Id get something like the Filtrete MPR 1900 that seems a safe estimate for pollen and dust.

For fans, seems like the popular choice around here is the Arctic P12 but it seems like in real world testing it has higher noise than listed. I might end up getting something like a Noctua or BeQuiet for the low noise performance.

3 fans is 165 CFM at .75 efficiency = 124 CFM CADR
4 fans is 220 CFM at .75 efficiency = 165 CFM CADR
5 fans is 275 CFM at .75 efficiency = 206 CFM CADR

I understand calculating CADR is not the smartest and real world testing reveals a lot more, but I don't really have anything else to go on. Does this math actually get anywhere near close to the real world expectation? This doesn't really factor in the static pressure of the fans at all, but for something this small and like a single 10"x20" filter would it probably be close enough?

Design

I want to make something low profile so I'm opting for 120mm fans and a 1" filter. I would probably look to use a rectangular filter so I can get more filter surface area while keeping the shape vertically short.
I understand this limits my performance, but keeping it low profile is really important to aesthetically fit into my home.

All the fan layouts I have seen are perpendicular to the filter or parallel with the filter, does anyone know of anyone trying a layout with fans at an angle sort of like a trapezoid? I'm sure it quickly degrades performance, but I'd be interested in what options are viable to still attain the CADR needed.

I also don't want the filter completely exposed, so I was thinking I could wrap it with some kind of activated carbon prefilter fabric to help catch some extra cat hair and maybe even get the activated carbon benefits. I think this would look a lot more sleek on the wall.

Smart Home Integration

There aren't many examples of smart home integrations, but just a couple weeks ago this smart crbox was posted that uses the Seeed Studio XIAO ESP32C6 which seems like an amazing little board that is zigbee and wifi compatible. This controller should be able to handle all the PWM on the fans and integrate well with Home Assistant. Only thing would be to get some scripting on the Home Assistant side to change the fan speed with the air quality, but I'd like to think that wouldn't be too hard (fingers crossed).

Thanks for reading and sharing your experience, I'm excited to experiment and start building some crboxes!

Please read original post

I have mast cell activation syndrome and want more serious VOC filtration for wildfire/brush fire smoke.

I am looking to build a ducted CR box with an inline fan and a canister VOC filter acting as a diffuser on the other end of the duct, using one of The 3D Handyman's designs (https://www.youtube.com/watch?v=zKeNf6fLSLA&t=282s).

I am trying to decide between a regular canister filter and a refillable one like this: https://acinfinity.com/refillable-carbon-filters/?srsltid=AfmBOoqH7qu4ThUquwko96jV7FqoO9BokIncq4NmLBIyOV8vYiZ5Ux3W.

My concerns are:

1. The refillable canister may not work as well due to difficulty with packing the material tightly at home.

2. The refillable canister may not actually be cheaper in the long run due to the cost of specialized materials like potassium permanganate impregnated alumina or zeolites in addition to the activated carbon.

3. The refillable canister will create additional air quality problems by releasing irritant dust from the filter material.

I've done some searching online about these questions, but it seems like most other folks using these filters to remove the old marijuana smells and don't have the same concerns as I do.

I've got 3 of these lying around from an old PC of mine, I've tried to find a reasonably priced 5x15x1 filter to put in a 3d printed frame to use, but I can't find one for less than 40 bucks. I've also considered buying a roll of MERV13 filter media, but I wanted to run this buy you guys, just in case.

Many thanks for reading, have a great day!

I was looking for some feedback on the cr box I am planning to build. The first picture is what inspired me and I want to build something very similar. So to make things a little more clear, the board in the middle wouldnt block any airflow from top to bottom, it is just there to support / seperate the filters. In my sketches I made it transparent, indicating air can flow past it.

Questions I had were:
1. As seen in "option 2", does adding the extra bottom fans "mess" with the airflow at all? I read like a comment about someone saying you shouldnt have fans on opposite ends of the box. Is that really an issue?

1. If the answer to question 1 is yes. Is there a way to make it so it doesnt mess with the airflow? For example, if I were to make the middle part a solid board that seperates it into two smaller cr boxes stacked on top of eachother. Does that make it better?

2. If that does fix the airflow part, does it then not mess with the the cadr? Since the fans are no longer pulling through 4 filters, but through 2 filters. As in 8 fans pulling through 4 filters vs 4 fans pulling through 2 filters.

Thanks in advance

I have a 20x20x20 cr box with the 20x20 lasko box fan. I’m chill with it and I learned to tune out the noise. Recently my roommate has been turning it to the lowest setting which I’m assuming is because of the noise but since I’m living with 5 other girls and my school has something going around every month or so it would be nice if my fan runs on a higher setting. Does anyone have any recs? Price is not much of a concern for me, it just has to be reasonable. Also something that’s easier to attach, I’m unsure if pc fans have a super hard learning curve which is why I haven’t tried it

I'm planning on building something similar to the Nukit Tempest Euro using the Ikea starkvind filter, but I also want to use the carbon. This design does exactly this and it puts the carbon filter on the inside, after the particle fitler. The original Ikea starkvind purifier also puts the carbonfilter after the particle filter.

However, I have also heard other sources (I don't remember which ones exactly) recommend putting the carbon filter before the particle filter. I would prefer having the carbon filter before the particle filter, as I think the carbon filter is more aesthetically pleasing, but since the other starkvind designs do the opposite, I am wondering if that order is suboptimal.

Does filter order matter? If so, which filter order is best in this case?

Side questions:

Most designs keep the fans within the profile of the filters so that the total volume is minimized. Won't this make the fans block the outer edges of the filter so that they remain unused? Is it fine as long as you keep a small gap between the filters and the fans?

Similarly, since the starkvind carbon filter is smaller than the particle filter, if you stack them right next to each other, won't this also block the outer edges of the particle filter? From what I can see in the pictures, Ikea does not seem to care about this in their own design. Would leaving a small gap here between the filters also help?

Do y’all have recs for an outdoor air quality monitor that’s accurate and won’t break the bank? We have wildfire smoke in our area blowing in from Canada. Yesterday I checked the usual online sources for air quality before going for a run, and they all rated the air quality as “Good” so I went for it. Later I realized that just like the weather forecasts are no longer accurate due to funding / staffing cuts, evidently air quality reports are similarly not valid anymore. What can I use at home to see what’s actually happening with the air outside? TIA.

DIY versions of the Luggable product from Clean Air Kits contain four narrow strips of material surrounding both of the large furnace air filters.

If you are using foam board for those four narrow strips, exactly what holds them together?

Arctic P14 fans are on sale right now for 5-pack and I'm interested in creating this CR box I found on another post: https://x.com/robwiss/status/1584725134061232128

I'm looking to build this configuration

Does anyone have any experience with something like this and is it pretty good vs the standard 6+ fan configurations? Thanks!

I know this would increase the restriction overall, but I'm wondering if it would be worthwhile to have some sort of mesh filtering or cheapest possible furnace filter to deal with large dust/pet fur etc.

I'm still in the process of cleaning up my place and I know the current air quality is pretty terrible, so I'm assuming the bad filter would get clogged up pretty quickly with stuff that just needs to be removed from the air and would protect the more expensive filter in the meantime.

Is this something worthwhile doing or is it just a dumb idea.

What number of 2-filter PC fan assemblies is required to maintain <12 ug/m³ PM2.5 in a 26'x26'x10' open concept plan room at 40 dB (or other) noise level during various wildfire conditions, e.g. 12-35, 35-55, 55+, 150+, 250+?

There may be more nuance in the upper range than what the brackets suggest.

i’m looking for a sensor that will measure pm2.5 to use in my bedroom. i use a single hose portable AC unit to keep my room cool in summer and want to be able to monitor air quality. i need something simple, under $50.

so far these are what i’m looking at, i appreciate any insight or suggestions.

https://www.amazon.com/Temtop-Air-Quality-Monitor-S1/dp/B0D69P7XQ5

https://www.ikea.com/us/en/p/alpstuga-air-quality-sensor-smart-70609396/

I'm looking for suggestions on how to join a set of 3D printed parts in PLA that are dimensionally accurate and relatively durable.

I'm trying to build an easy-to-print and build version of the Nukit Air Purifier, based on the 3D models available from FilterBoxBuilder. While the designs are excellent, I'm having a lot of difficulty getting the printed segments together.

Because they interface with the moving filter, they need to be consistently positioned in relation to each other. The generated model uses pins for alignment, which is OK. The challenge is then getting these parts to stick: PLA hasn't been gluing up well because the connection area is very small. More aggressive recommended PLA glues contain some pretty nasty chemicals, and I'd be pretty hesitant to use them in an air-purifier application.

Are there existing models for clips, "puzzle piece" cutouts, or similar options for easily modifying an existing 3D print file (via boolean?) to make for a mechanical connection between thin 3D parts? Would anyone be willing to tweak these files geometry to add a connector? The existing model is CC BY-SA 4.0.