The CR box isn't folklore — it emerged from aerosol scientists during the pandemic and has been measured repeatedly since. Here is what the evidence actually shows, in plain terms.
681 m³/h CADR, MERV-13, under 35 dB — powerful whole-home clean air — no proprietary lock-in, ships from the UK.
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Independent testers (including well-known enthusiast and academic groups) have measured CR-box CADR in the hundreds of cubic metres per hour — comparable to, and often exceeding, purifiers costing several times more. The reason is simple physics: large filter area plus a high-airflow fan.
Particle reduction in real rooms
Studies and field measurements show meaningful reductions in indoor PM2.5 and airborne particle counts when a well-built box runs in an occupied room — the basis for its adoption in classrooms. For the schools context, see CR boxes in schools and offices.
Airborne disease context
Because airborne respiratory particles travel on aerosols in the size range MERV-13 captures, raising a room's air-change rate with filtration lowers airborne particle concentration — one layer among several. See are CR boxes effective for COVID.
Sensible caveats
Evidence supports filtration as one effective layer, not a cure-all: build quality, sizing and running time all matter, and filtration complements ventilation rather than replacing it. Deeper dive: research & efficacy.