Multiple Brands (DIY design) - Corsi–Rosenthal Box (DIY)

3D handyman on youtube has better instructions I found. https://m.youtube.com/watch?v=KobogQMf_Xc https://m.youtube.com/watch?v=eYOvnqoW4H0 box fans work but they are loud. he recommends some other designs that work better. I like the work CR did on theirs because they recommended just tape or glue the seams together - much more realistic for someone at home, and the box fan is the perfect shape for ease of assembly.

I have a levoit core mini on my desk at work. However, I use it as a supplementary purifier to a DIY 16"x20" Coris-Rosenthal purifier that sits in the corner of my office, so I can't really tell you if the levoit alone makes a major difference in air quality. I can say that bought it December 2024 and haven't had any issues with it, and it is very quiet on fan speeds 1 and 2. I keep it on 2 and only bump up to 3 when someone enters my office and comes over to my side of the desk. Level 3 is noticeably louder than Level 2 (but still much quieter than my $15 floor heater), so if you work in an open-office environment you'll have to judge if level 3 is too loud. If you're interested in DIY options, let me know and I can provide a link.

Corsi Rosenthal Merv 13 CRboxes, and specifically Computer Fan Merv 13 CR boxes vastly outperform HEPA purifiers in every metric: acoustic, Energy consumption, and particulate matter removal Plenty of scientific literature to back that up https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Corsi+Rosenthal+Boxes+vs+hepa&btnG=#d=gs_qabs&t=1754052122891&u=%23p%3DG_S0ZOylYNAJ https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Corsi+Rosenthal+Boxes+vs+hepa&btnG=#d=gs_qabs&t=1754052159338&u=%23p%3DiAc9fHufim0J https://chemrxiv.org/engage/chemrxiv/article-details/632dd805e665bda75a1002f8 What I find to be interesting though is how rare it is for someone with the tools to test HEPA crboxes for some reason, nor do they test them in independent labs or at least post the data on why the don't along their Merv 13 data. It's literally just a 2x-4x filter layout increasing the filter surface area and lowering the static pressure needed while using vastly more efficient fans in framing intended to accommodate a wider array of filter sizes

a winix 5300 or 535s are the sweet spot for price and CADR. Corsi Rosenthal for the DIY will beat anything on this list though

If you want a cheap and effective air purifier for your living room/kitchen area (not for the bedroom because they are noisy) consider building a triangular Corsi-Rosenthal box with a pair of MERV-13 filters or above. Pros: Corsi-Rosenthal boxes move far more air than most off-the-shelf air purifiers and given that you build them with the filter of your choice they can be adapted to your needs. I have mine with a MERV-11 filters but I'm not a sensitive person. Plus they're far cheaper to get and replace the filters than a brand purifier that will keep you slave to their replacement parts. Cons: they are bulky which is why I built the triangle design for my one-bedroom. They are a bit loud at max, so I run them in the living room when I'm going to bed (can't hear them with the door closed). You need to be handy with tape and scissors.

That's just lazy craftsmanship, you are wasting so much of a square filter on a circular airflow path. Also, I like to buy my filters on marketplace, I got 5 MERV-11 for $15, but they are 20x25 inches so they can't be set the way you mentioned. And using multiple filters at a time gives you greater airflow (important if you are filtering a large apartment).

the fan doesn't matter, as long as it is the standard 20x20 inches box, they are all made in China and come with 3 settings. Just get the cheapest one on markeplace (ideally less than $20), open it up, give it a good wipe to rid it of dust and grime (or buy a new one lol), ready to go.

made 1 yesterday, works great, also did a triangle version for my bedroom

A Corsi Rosenthal Box is what I run 24/7. It filters a massive amount of air, and is only as costly as a box fan and four furnace filters. I get MERV 13 filters. [https://engineering.ucdavis.edu/news/science-action-how-build-corsi-rosenthal-box](https://engineering.ucdavis.edu/news/science-action-how-build-corsi-rosenthal-box)

I was afraid to say this, so thanks for speaking up. The DIY solution absolutely blows away anything else I have ever used. If you are really wanting the same efficiency with better aesthetics, there is a guy on ETSY that prints housing in all different shapes and sizes.

You need 2 box fans (living room & bedroom), 2 20x20 3M Filtrete Allergen & Odor Reduction Air Filters, and 4 bungee cords (2/fan filter) or a roll of duct tape. See the video linked below from the University of Michigan med school for how to set it up. This works better than a typical air purifier because it filters the air quicker due to the larger surface area. In 3 or 4 hours the smells will be gone, maybe 6 hours if the smells are extra strong. I’m a lifelong severe asthmatic and have used that setup for over a decade. It works great. University of Michigan DIY Air Purifier: https://www.youtube.com/watch?v=kH5APw_SLUU When I last priced it (6-9 months ago), if you have to buy everything, it was around $50 per DIY purifier.

Yes. The filter I recommended is allergen + odor reduction. The wrapper is green and the filter has carbon on one side. If there’s a large hole in the packaging, grab a different filter (carbon only absorbs so much). Once you’ve got the VOCs out, I’d switch to a 3M Filtrete filter that’s numbered 1900 or higher. Avoid their smart filters, just replace every 3 months.

Why don't you want it cleaning the air 24 hours a day though? I have a DIY corsi box and a levoit 300 in the bedroom running all the time. Bonus is it provides white noise at night. I leave all of the air purifiers on in the house because air is always circulating between rooms and I count the cadr as overall house cadr