Blueair Blue Pure 211i Max moves more air (CADR) and covers a larger room than KNKA APH4000.
Which purifier has higher CADR?
Blueair Blue Pure 211i Max has higher CADR (435 vs 226 CFM).
Which purifier is quieter?
KNKA APH4000 is quieter (22 vs 23 dB).
Which purifier covers a larger room?
Blueair Blue Pure 211i Max fits a larger room (about 674 vs 350 sq ft recommended from CADR).
Which purifier has better smart features?
Blueair Blue Pure 211i Max lists Wi-Fi or app control; KNKA APH4000 does not.
Which purifier has longer filter life?
Filter replacement interval is not published for either model.
Bottom line
Blueair Blue Pure 211i Max moves more air (CADR) and covers a larger room than KNKA APH4000.
| Metric | Blueair Blue Pure 211i Max | KNKA APH4000 |
|---|---|---|
| CADR (smoke) | 435 CFM | 226 CFM |
| Recommended room size | 674 sq ft | 350 sq ft |
| Claimed coverage | 3235 sq ft | 1695 sq ft |
| Noise | 23 dB | 22 dB |
| Filter type | HEPASilent | HEPA |
| Filter interval | — | — |
| Smart features | None | None |