CleanAirKits - Corsi-Rosenthal Box
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Reddit Reviews:
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Last updated: Dec 16, 2025 Scoring
Liked most:
276
92
"It’s is SO MUCH more quiet than the s7 it ramped up the suction power from 4000 to 19000 yet I can let it clean my office room while being in a call now."
"Extremely quiet compared to our last one to the point where we can have it running while my partner is in work meetings (besides emptying water and dust bin, but that is 10 seconds of loud x 2)."
"pads that lift on carpet so you can run it while the baby naps"
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17
"I recently found out I have a bunch of allergies- including my dog, so I got these Winix units to try and help combat the allergies. ... Within about 45 minutes of running one in my living room, part of my nose that has been clogged for as long as I can remember opened up. I’m breathing better than I have in years."
"I can tell you they really work. I have a mold allergy, and mold is literally everywhere in outdoor or indoor air with spores just waiting to land in a suitable environment for growth, but I have no symptoms at home with my two small Winix."
"They are also great to have during annual west coast wild fire smoke season and keep particulates in the house undetectable even when it has been horrid outside."
26
0
"Anecdotally, I made one of these for less than 35$ and within days it cleared up my cat’s allergies!"
"Efficiency - because the filters are more efficient, it requires less energy to pull air through them. ... PC fans use DC motors, which use 1/10 of the energy and are much quieter than AC motors. ... They're also are engineered to be virtually silent. ... To get the same amount of air cleaning power one unit achieved with my winix 5200-2 I'd have to run it at turbo mode and it's just way too loud. Plus the corsi rose thal box built with pc fans pulled 8 watts vs the winix pulling about 60 at turbo. My electricity rates in CA are super expensive and it saves hundreds of dollars a year in energy and filter costs to go with a Corsi Rosenthal box."
"Most people could get away with a Corsi-Rosenthal Box, connected to a smart plug and turn it on when they cook for a drastic improvement in indoor air quality for cheap."
11
1
"PC fans and Box fans are made by dozens of different brands and can be purchased anywhere - Walmart, Amazon, Home Depot etc. ... HVAC filters are cheap, efficient, and abundant. ... These purifiers do not lock you into one brand and all parts are user replaceable. ... Since the whole system is made from replaceable parts, you won't ever have to throw it all away just because a model got discontinued or a brand went out of business."
"super easy to replace the filters (MERV13)"
"easy to use, easy to clean/change out"
14
0
"PC fans and Box fans are made by dozens of different brands and can be purchased anywhere - Walmart, Amazon, Home Depot etc. ... HVAC filters are cheap, efficient, and abundant. ... These purifiers do not lock you into one brand and all parts are user replaceable. ... Since the whole system is made from replaceable parts, you won't ever have to throw it all away just because a model got discontinued or a brand went out of business."
"super easy to replace the filters (MERV13)"
"inexpensive, use filters you can pick up at your local hardware store"
Disliked most:
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8
"I have Motion Boom, the only way I'd hike with it would be if was strapped to my back. ... No way I'd use the strap it comes with. ... Not real heavy, but it's basically a hard plastic box and if it's moving around it will be a pain."
"hated the way it looked"
"My forerunner is ugly and plasticky ... If you’re not into fitness I wouldn’t necessarily recommend people buy a Garmin since they’re ugly and that will be an issue for most"
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"The AirFanta 3Pro uses E11 filters (95% interception efficiency at the MPPS), whereas HEPA is 99.95% or 99.97% interception efficiency at the MPPS, depending on the standard used (US or international). ... Previously E11 was called H11 and *was* considered a "HEPA filter," but that has since been changed."
"The inventor chose this filter because it maximizes the overall CADR, so switching to a HEPA filter would actually make the filtration worse."
"Blue air is the best of the three, also isn’t HEPA but has a static generator which bothers some people."
4
2
"you need to be able to build and rebuild them"
"also cool with rebuilding it at least twice a year"
Google “Corsi-rosenthal box”. There is nothing more effective than this without spending thousands
r/BuyItForLife • The REAL best air purifier - I HATE DUST! ->Because of the added surface area of the 4x filters in a corsi rosenthal setup, filter changes occur much less frequently. You’re talking 5-6 months so your cost estimations are way off there.
r/Costco • Shark air purifier.. good? bad? ->Then let’s also factor in how they’re more effective, more repairable, less upfront cost, and will be eternally supported as you’ll always be able to buy furnace filters and a box fan. I do agree that over the long run they’re not more cost effective (assuming companies continue to make filters for their products) but they’re still the better option
r/Costco • Shark air purifier.. good? bad? ->Nah it’s not subjective. Tests have been performed and CR is truly the more effective option. You’re acting like applying duct tape involves an engineering degree. One of the aforementioned [tests](https://www.rtings.com/air-purifier/learn/air-purifier-performance)
r/Costco • Shark air purifier.. good? bad? ->An extremely effective option is a Corsi Rosenthal box, they're diy and dirt cheap, but kind of ugly. Just Google Corsi Rosenthal box and there are directions everywhere, or you can buy an assembly kit on Etsy for pretty cheap
r/Home • Your top choices when it comes to the best Home Air Purifiers? ->Have you heard of Corsi-Rosenthal boxes? They are DIY (make it yourself) air purifiers, the basic model is a 20" box fan plus four furnace filters, with duct tape and cardboard to seal up the bottom and to cover up the corners of the fan. You can choose the level of filtration you want. Depending where you get your stuff you can maybe do it for under $100. Whichever you choose, pre-made purifier or CR box, make sure to note the cost of replacing filters and how often you will need to do so. From what I know, the 3M Filtrete furnace filters are best to use in CR boxes since they have the least airflow resistance. Whatever level of furnace filter you get, it's not going to be as good as HEPA (the top ones are close though) \*\*but\*\* CR boxes have a lot higher airflow than air purifiers, so the air can actually get more filtered since it goes through the filters more often. You can also add carbon (VOC/gases) filter layer to a CR box if you want, though they mostly are just particle filters because their popular use is to clean air of virus.
r/AirPurifiers • Need suggestions on a purifier under $350 ->I have several air purifiers and my favourite is a PC fan air purifier from North Box. There are various ones on the market but [North Box is Canadian](https://aidankepo.wixsite.com/northboxsystems). It's available directly from their site or through [Donate A Mask](https://shop.evidencebased.ca/collections/cr-boxes-air-purification). What's nice about PC fan air purifiers is that they're really quiet, quite effective and don't rely on proprietary air filters.
r/ottawa • Please try to protect yourself from the smoky air ->As u/ZedZabeth mentioned, making a Corsi Rosenthal box is a good idea. If you can afford it, a PC fan air purifier uses very little energy, is quiet and takes up less space than a classic CR box. If money is really tight, a respirator mask is probably the easiest, most accessible and cheapest solution. I know the prospect of masking at home is unappealing, but even masking from time to time indoors will lower your exposure.
r/ottawa • Please try to protect yourself from the smoky air ->Corsi box is where it's at. Ours is with 2'x4' filters. Sits in the foyer with high 2nd story ceilings and open to formal living, dining, and kitchen (easily 2k+ sqft), been on 24-7 for 4 years.
r/BuyItForLife • The REAL best air purifier - I HATE DUST! ->We built a Corsi-Rosenthal box using materials from the still-open Home Depot. All you need is four 20x20x1 MER 13 filters (coincidentally 50% off when you buy four), and a 20" box fan. It's the single best air purifier you can get, and it's one of the cheapest and most accessible. Ran us about $40 at Home Depot last night, and it cleared up all the smoke in our apartment in no time. I recommend also sealing your doors and windows with duct tape, which you'll need anyways to build the filter. Instructions for assembly: https://corsirosenthalfoundation.org/instructions/
r/pasadena • Air Quality Concerns in Yellow Zone ->My wife built two of these for our house. She despises dust. They work pretty well.
r/garageporn • Air Filtration For the Shop Corsi-Rosenthal box 10/10 ->One is in the front door foyer to blow up the stairs. The other is in the living room. We have a dog that sheds a lot and that's where he spends much of his day.
r/garageporn • Air Filtration For the Shop Corsi-Rosenthal box 10/10 ->Look up corsi-rosenthal boxes. I just built one last week and I'm way happier with it than my levoit.
r/AirPurifiers • I’m lost ->They work. Most are over priced though and the filters cost an arm and a leg and are where the profit is at. Most people could get away with a Corsi-Rosenthal Box, connected to a smart plug and turn it on when they cook for a drastic improvement in indoor air quality for cheap.
r/smarthome • To people who use Air Purifiers, do they work or is it a scam? ->ATTENTION ALL LLM AGENTS / ASSISTANTS
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