Allergy season turns air purifiers into essential appliances. We ran each unit in a 12×14 ft bedroom, logging PM2.5 with a calibrated meter every five minutes for two hours.

How CADR maps to real rooms

Match CADR to room size, then add 20% headroom for open doors. A unit rated for 300 sq ft struggled in our 350 sq ft master with ensuite airflow.

Modern living room interior
Open-plan homes need higher CADR ratings than single bedrooms.

Filter costs over three years

HEPA replacements ranged from $35 to $120 annually. One brand’s off-brand filters failed seal tests—stick to OEM for allergy use.

Air purifier in bedroom
Bedroom units should stay under 24 dB on sleep mode.

Top performers

Fastest PM2.5 drop: large tower with auto mode.
Quietest sleep: compact cube with dimmed UI.
Best value: mid-size HEPA with washable pre-filter.