Brisk Box (CleanAirKits)

If you're talking about producing en-masse, the lasko box fan build is fast and easy, and you don't need whatever specialty piece of plastic/board that is showin in black in the photo. Similarly, you will lose some of that simplicity for time because you'll need to hook the fans up to the power supply, screw them and the grills into the board, etc etc. If production time and people-power is the pinch point, the box fan method is a faster build. Fewer steps, fewer materials, fewer tools. HOWEVER: Depending on the application, I'll echo what RescuePenguin said. I have some of the CleanAirKits purifiers running in my home at all times, and those use PC fans. I can barely hear them. The air purifier I have at work I keep on low most of the time because if it's running full speed the background noise makes a big difference in how well people can hear and talk in a mostly-quiet room. If I had a filter based around the 20 inch box fan, I'd probably have the impulse to switch it to low or off so I could hear and be heard better.

Although the classic Corsi Rosenthal box based on a 20-inch box fan is a clever idea, I don't see myself ever using one. It takes up lots of space, it's not very portable, and it's loud. I prefer my [box fan air purifier](https://www.reddit.com/r/crboxes/comments/1hi3z6h/portable_box_fan_air_purifier_with_shroud/) that uses just one 1-inch-thick MERV 10 filter or one 4-inch-thick MERV 13 filter. This design takes up MUCH less space, and I can carry it with just one hand. I do have a Brisk Box Kit from Clean Air Kits. It's a Corsi Rosenthal box with an array of PC fans. While it takes up lots of space and isn't very portable, at least it's QUIET. So I don't have to turn it off because of noise.

Jim Rosenthal (half of the duo behind the Corsi Rosenthal box) did an experiment comparing a Corsi Rosenthal box using MERV 11 filters against a high-end commercial air purifier using a HEPA filter. You might think that the MERV 11 filters (with lower filter efficiency than MERV 13 filters and MUCH lower filter efficiency than HEPA filters) would have been left in the dust (pun intended). In contrast, the cheaper and cruder Corsi Rosenthal box outperformed the commercial air purifier with the HEPA filter. In other words, the cheap and crude air purifier was MORE effective at cleaning the air than the expensive commercial air purifier.

I got a basic brisk box 6 months ago using 3M 1900 filters on it. Placed it in the room with cat litter boxes and it made a huge impact on the amount of dust. Other units I tried have struggled to keep up. Highly recommend clean air kits.

If the room is only 100 SQ ft, one air should be enough. Depending on your budget, Clean Air Kits has quiet air purifiers. Their Brisk Box would work well. They're pretty pricy though. Another option is the Levoit Vital 200s. It's rated for a larger room (390 SQ ft) but you could run it at a lower and quieter speed and get good air cleaning.[Vital 200s Review](https://housefresh.com/levoit-vital-200s-review/) Right now my daily mask is the BNX boat style N95. For a while I was wearing Kleenguard duckbill N95. I can reuse the BNX masks but generally I don't after an 8 hour day. I'm starting to reuse my masks a bit more- wearing them twice before tossing. Most of my work day is in my office solo with the air purifiers running. Today I was in a fairly crowded room wearing my mask for the second time. I tossed the mask once home. Probably would have been better to wear a fresh mask to an event I knew would have a lot of people. I didn't have any extra masks on hand. I had a box of extra masks at work but recently ran out.

Corsi Rosenthal boxes have good CADR. They're DIY box fan air purifiers. Plenty of YouTube tutorials if you ever wanted to try your hand at it.

This right here. I have one of these in my apartment and am planning on getting a second one. Easy to replace fans, easy to replace filters, it's just best option.

Make your own "brisk box" from CleanAirKits. I do 12x12x1 boxes and I think I've gotten the price of the fan lid to about $80 DIY. 2 of those would be better than half the HEPAs in your budget. More so than just a filter, you should have a doffing process. E.g. Figure out your air volume, CADR (clean air delivery rate) and then you will have an ACH (air changes per hour). This lets you make informed decisions about how much filtration you buy and how safe that filtration makes you feel. I aim for 10-12 ACH and the recommendation I see most often is 12.

Check out cleanairkits.com. Their luggables look sharp and fit the criteria.  But they have slightly louder fans than their Bris box design the bros box isn’t as attractive. No other manufacturer will move the same amount of air at the decibel of these units.  But there is no speed setting, they’re just quiet. Every other purifier will clean less air or be louder and you’ll have to turn down the fan speed.

You need a couple corsi rosenthal boxes. Each one will run you about $90 in today's prices. They perform as well as a $1000 air purifier for 1/11th the price. r/CRBoxes can help. [https://youtu.be/hIuH-2naozI?si=xNUdt\_djOjXdJKja](https://youtu.be/hIuH-2naozI?si=xNUdt_djOjXdJKja)

Unfortunately that website has been completely taken over by affiliate link BS. 95% of air purifiers sold online are complete garbage. Have tried many over the last 15 years due to asthma and allergies. The only cost effective solution I found that actually works (have an air things air quality monitor so I can tell by turning on and off air purifiers) is a box using home furnace fan filters. I got one from clean air kits that uses computer fans and it's super quiet so you can sleep with it on. Mine is 4x 20*25" filters. You can make your own with box fans but they will be crazy loud. The 4 fan one is good for a small room. https://www.cleanairkits.com/?ref=ANNALE&gad_source=1&gad_campaignid=22709004639&gbraid=0AAAAA_ODbriF_jyz8Gjm983QOPyONyoIt&gclid=CjwKCAjwt-_FBhBzEiwA7QEqyI5KZ5R9_7eGZZIs3i8JuZzTyN3fsBU8lDCdZe9VxwvN-gMl4hPouhoCCpMQAvD_BwE And you don't need the most expensive filters either, in fact they work better with the mid range ratings as they have way more airflow. Mine are 10s or 11s I think...

PC fan Corsi-Rosenthal box is definitely the BIFL version. Simple parts that are all easy to replace, and not locked in to a proprietary filter.

If you look at cost, CADR/CFM, and noise, nothing on the market beats [Clean Air Kits](https://www.cleanairkits.com/?ref=CCCircle), period. Data to back it up, any entry in gray is a setting that is louder than 50db: [https://docs.google.com/spreadsheets/d/1kQMWNyKfkB0K8A4\_yXMrSAb-CruVl9lASJEpLGLtS8o/edit?usp=sharing](https://docs.google.com/spreadsheets/d/1kQMWNyKfkB0K8A4_yXMrSAb-CruVl9lASJEpLGLtS8o/edit?usp=sharing)