CADR (Clean Air Delivery Rate)
CADR (Clean Air Delivery Rate) is the industry-standard metric for measuring air purifier effectiveness. It indicates the volume of clean air produced per minute, measured in cubic feet per minute (CFM). A higher CADR means faster and more effective air cleaning.
CADR is tested and certified by the Association of Home Appliance Manufacturers (AHAM). It measures performance against three types of particles: smoke (0.1-1.0 microns), dust (0.5-3.0 microns), and pollen (5.0-11.0 microns). For effective air cleaning, choose a CADR rating that matches your room size - multiply your room's square footage by the ceiling height, then look for a CADR at least 2/3 of that volume.
CADR measures cubic feet per minute (CFM) of clean air delivered
Tested for three particle sizes: smoke, dust, and pollen
Higher CADR = faster air cleaning in your space
Match CADR to room size: need 2/3 of room volume for optimal performance
DIY Corsi-Rosenthal boxes typically achieve 300-600 CFM CADR