This is with the Utilitech 20″ Box fan – 58 Watts when cranked to max, as measured by Jim Rosenthal. The measurements below are for:
- No filter attached.
- 1 filter attached – 1″, 2″, 4″
- Box filter – the full Corsi/Rosenthal Box attached.


This with the Lasko 20″ Box Fan – 89 Watts when cranked to max.


Exactly. The fan on high for the Corsi/Rosenthal box used 54 watts. The ELGIT air cleaner (also known as a Banker’s Lamp) used 60 watts. Just in case someone doubts the data – here are the pictures. https://t.co/jpK81qqa2F pic.twitter.com/ysLQKGvSmh — Jim Rosenthal (@JimRosenthal4) August 26, 2021
David Elfstrom also measured both with the shroud on the single filter version, which makes the fan operate more efficiently.
Utilitech/Hurricane with 13.5″ shroud: 350 CFM, 52 W!
Lasko with 15″ shroud: 350 CFM, 74 W !


Sources:
Optimization so far, with 3M Filtrete 1900 20x20x1
Lasko with 15″ shroud: 350 CFM, 74 W
Utilitech with 13.5″ shroud: 350 CFM, 52 W!
Actual flow will be slightly higher when measured at outlet with backpressure compensation feature in the flow capture hood. /14 — David Elfstrom (@DavidElfstrom) August 16, 2021
Optimization so far, with 3M Filtrete 1900 20x20x1
Lasko with 15″ shroud: 350 CFM, 74 W
Utilitech with 13.5″ shroud: 350 CFM, 52 W!
Actual flow will be slightly higher when measured at outlet with backpressure compensation feature in the flow capture hood. /14 — David Elfstrom (@DavidElfstrom) August 16, 2021