Air purifier for a 400 sq ft room

Minimum smoke CADR: 267 cfm with an 8 ft ceiling, 300 cfm at 9 ft, 333 cfm at 10 ft.

Based on AHAM's 2/3 rule (smoke CADR ≥ 2/3 of floor area, scaled up for ceilings above 8 ft). For wildfire smoke or allergies, many people size up; the "headroom" column shows models with at least 50% more CADR than the minimum.

45 qualifying models, cheapest to run first

*Estimate: ENERGY STAR annual kWh × U.S. average residential rate 18.31¢/kWh (EIA, July 2026 (preliminary)). ENERGY STAR's annual figure assumes 16 hours/day of operation under the DOE test procedure.

9 of these have at least 50% headroom. Not sure of your room size? Use the room calculator.

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