Find your filter

Tell us your room size and we'll show you air purifiers that can actually keep up with it - or pick the contaminant you want gone from your tap and we'll show you the water filters proven to remove it. Results come back best score first, and on the water side we only show you units that are genuinely certified, not ones that merely claim it. Already own the unit? Type its model or part number and jump straight to its scorecard and replacement cartridge.

Your room size (sq ft)Ozone-free only

For about 4.8 air changes per hour, you want a smoke CADR of at least 162. 8 units qualify.

7.1Levoit Core 300SCADR 175 · ~271 sq ft
7.1Levoit Core 400SCADR 259 · ~401 sq ft
7.1Levoit Vital 200SCADR 289 · ~448 sq ft
5.0Honeywell HPA300CADR 320 · ~496 sq ft
4.3Dyson Purifier Big+Quiet Formaldehyde (BP03)CADR 200 · ~310 sq ft
4.0Coway Airmega 400CADR 400 · ~620 sq ft
3.9Alen BreatheSmart FlexCADR 230 · ~357 sq ft
3.3Shark Air Purifier 6 (HE601)CADR 175 · ~271 sq ft

For air, we size a unit to your room by how fast it actually cleans the air (its CADR) using the AHAM 2/3 rule - roughly CADR times 1.55 sq ft, enough to turn the room's air over about 4.8 times an hour. For water, you'll only see filters listed on an official NSF, WQA, or IAPMO database for the contaminant you picked.