Stop Building the Corsi–Rosenthal Box

It belongs in the Trash

Jul 22, 2022

https://en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box

A Corsi-Rosenthal Box only filters 62% of Virus Particles. It doesn’t use a real HEPA filter. It’s MERV 13, NOT MERV 17 REAL HEPA.

The Corsi-Rosenthal Box uses MERV 13. You are INTENTIONALLY giving the people viral infections when you recommend MERV 13 over true HEPA aka MERV 17.

Corsi Box versus a real Purifier with a smart designed fan

The CorsiBox is a DIY Air Purifier that has gotten popular since the Pandemic started. I am here to tell you, please stop recommending/building this device. It does not save you money and does not filtrate particles well. Any off the shelf air purifier is not only cheaper, already built, comes with a warranty, uses far less wattage, emits less EMF.. but also captures the actual smallest particles significantly quicker.

Here is a tutorial of how to build such a device for “less” than $175. Note that these devices uses an extremely inefficient fan motor that takes far more wattage than a real dc fan motor from a HEPA purifier.

On A Back-To-School Supply List: Materials For DIY Air ...

At the root of it, any HEPA purifier is a fan and a filter. That is it. No bells, no whistles.

Sometimes people claim to have built such devices for cheaper.

The Corsi box doesn’t use real HEPA filters, the DIY suggests to use MERV 13 filters, which is not real HEPA. Real HEPA is rated MERV 17.

Further, MERV 13 has a range of filters. It’s not one standard either. MPR 1500 is MERV13. MPR1900 is also MERV 13.. even though the higher MPR rating filters FAR more particles.

MERV (Minimum Efficiency Reporting Value) Ratings & Filters

Real examples of two MERV 13 filters with different particle capture ratings

The Corsi Box does not address the issue of pressure drop across multiple brands at the same filter rating. Translation: Name Brand Filters have less pressure drop over time.

In a biased testing by aerosol experts promoting this box, their own data shows how badly it performed.

https://built-envi.com/portfolio/air-cleaner-testing/

The Corsi Box does not effectively capture the most important particles.

Smoke Particles (0.5-3um) only had 168 CADR (cfm). That’s the size range where you would find most Covid aerosols to be. This device would never work in the classroom nor at home to protect you from virions.

Literally any other AHAM approved purifier works not only better but cheaper with less wattage. Here is the Winix 5500-2 for $179.

Here is the CADR from the same biased lab group. For Smoke particles, it had a CADR of 298 (cfm). This not only works better than the Corsi Box by nearly a factor of 2!!! But also, it uses LESS THAN HALF THE WATTAGE to achieve that goal.

Corsi Box takes 120 watts at high speed. A typical air purifier with similar CADR would take about 40 watts for the same fan speed. Why? DC motor is more efficient. Also, Corsi Box emits dangerous amounts of EMF since it does not use a DC Fan motor. Radiation is generally considered not a good thing. Please don’t ask for a source, you can take my word for it.

What HEPA purifier do I recommend? As stated earlier, literally anyone off the shelf with certification. They are sold locally at Walmart, Target, etc. No need to build a wasteful box that doesn’t even clean your air all that well. Never mind it does not reduce VOCs what so ever.

Coway has 250 researchers in their research & development department for air purifiers. Do you really think they spend all day debating making the fastest fan humanly possible? No. They are fully aware CADR is a pointless metric.