Skip to content

Does the Corsi/Rosenthal Box work?

    Click here to go back to all FAQ’s.

    Yes – it removes aerosols from the air.  How well does it work?  Very well.

    Dr. Marwa Zaatari, Chief Science Officer at Blue Box Air & ASHRAE Associate Member

    “It is the most cost effective purifier on the chart.” – this evaluation is from Dr. Zaatari, who regularly publishes an easy-to-understand chart that simplifies the often complex air clean marketplace.  It should be noted that this was the single filter version – so the 2/ 4/ 5 filter versions should perform even better.

    One large caveat – this is with the shroud on the fan. 

    UCDavis Western Cooling Efficiency Center found it delivers an equivalent performance to commercial air cleaners that cost 3x as much.


    And here is the final brochure/ PDF documenting all of their work.

    CBC Business Marketplace evaluated a MERV 11 single filter version of the Corsi/Rosenthal Box

    The $70 single filter MERV 11 version easily outperformed the $800 Dyson Pure Hot & Cool. Even more impressively, this was with NO shroud which increases performance by 47%, and a MERV 11 filter instead of a MERV 13 filter.

    The Built Environment Research Group at the Illinois Institute of Technology found these excellent results for the 4 Filter version of the Corsi/Rosenthal Box

    “… (T)he Built Environment Research Group has been independently evaluating the efficacy and potential for adverse consequences…” And they evaluated this version in September 2021.


    Why does it work so well?

    Jim Rosenthal, past president of the National Air Filtration Association and chief executive officer of Tex-Air Filters, discusses why the Corsi/Rosenthal Box works so well. It’s a fascinating article, but if you have no time:

    • The sheer amount of air flow from the CR Box is about 700 CFM (on only medium speed) versus the $900 HEPA filter it was compared with (300 CFM on maximum). 
    • It must be emphasized that Jim Rosenthal called for further research into this.
    • Here’s a graph of how it performed:
    • Yes – at least as good as a $900 HEPA filter.
      • Though to be crystal clear, the CADR for the MERV 13 filters is still being measured.  
      • Above is with MERV 11 filters.  The one you will make will have MERV 13 filters, so should be better.

    Dr. Richard Corsi discusses the Corsi/Rosenthal Box

    In this NPR Article, Dr. Corsi reported, “”People are now reporting 600 cubic feet per minute in clean air delivery rates. That’s phenomenal. That’s better than a lot of the more expensive HEPA-based portable air cleaners,”

    Speaking of Dr. Corsi – in this video he discusses the benefits of the Corsi/Rosenthal Box.

    This is anecdotal – and you have to have masking as well as air cleaning!


    Click here to go back to all FAQ’s.

    Did you find this FAQ helpful?
    Thumbs Up Icon 2
    Thumbs Down Icon 2