Cube: Higher Performance

With an estimated clean air delivery rate (CADR) more than twice as high as the single-filter option, and for the same footprint and slightly lower noise, the full Corsi-Rosenthal Cube box fan filter is our top recommendation.  If you are worried about the exposed filter surface, check out the chicken-wire shroud option at the bottom of this page!

Single filter: Lower Cost

For half the price and half the CADR, a single-filter version can be a good choice as a budget option, for smaller rooms (it only works as well as the cube in a room with half the volume), or if you prefer to keep the filter surface less accessible.  The EPA recommends that portable air purifiers blow upward, so you will want to build a stand, for example by using the box the fan came in and following our instructions here.  

Lasko 2-in-1: If UL is a must

Lasko has a nice product, the Air Flex 2-in-1, that incorporates a filter holder on the backside of a more premium box fan. This is a good choice if your school/district is adamant about only installing UL listed products in the classroom. It comes with a MERV10 filter that doesn’t do a very good job filtering out the smallest aerosols (37% in our tests), but you can replace the MERV10 with a better 1″-thick filter to improve performance (we like the 3M Filtrete MPR1500/MERV12 filter which performed well in our tests with the Lasko 2-in-1).  Unfortunately, Lasko didn’t shroud the front grille, but (if this still satisfies your school’s certification requirements) you can increase the filtration efficiency (and CADR) by 50% if you add a shroud with a 15-inch opening to the front!

Get In Touch

Please contact us with any questions you may have about these lesson plans, suggestions for improvement, or information about how to make your ideas available for everyone.