PureAirIndex · Guide
CADR explained: what the number means and which one to use
Clean air delivery rate (CADR) is the volume of particle-free air a purifier delivers, in cubic feet per minute (cfm), on its highest setting. It is tested separately for three particle types.
Smoke, dust and pollen CADR across 247 certified models
Calculated from our ENERGY STAR snapshot. Particle size ranges are the approximate ranges used in the AHAM test method.
| CADR type | Particles | Min | Middle 50% | Median | Max |
|---|---|---|---|---|---|
| Smoke | 0.09–1 µm | 31 | 115–305 | 161 | 577 |
| Dust | 0.5–3 µm | 33 | 121–310 | 172 | 586 |
| Pollen | 5–11 µm | 36 | 131–332 | 188 | 450 |
In 24 of 247 records, pollen CADR is lower than smoke CADR. A single headline CADR can hide which particle it refers to, so always check the type.
How smoke CADR is spread across models
Why we size rooms with smoke CADR
Smoke particles are the smallest and hardest to capture, and they behave most like the fine particles (PM2.5) many buyers worry about. Sizing with smoke CADR is the conservative choice. Use the air changes per hour guide to turn CADR into room coverage, or the room size calculator to find what your room needs.
What CADR does not tell you
- Gases, VOCs and odors: CADR measures particles only.
- Noise: CADR is tested on the highest speed, which is often the loudest.
- Lower speeds: CADR at quieter settings is usually not reported.
- Filter life or running cost: see the energy-use study.
- Health outcomes: CADR is an air-cleaning measurement, not a medical claim.
Sources and calculations: methodology.