Choose Alen 45i for higher CADR (255 vs 226 CFM) and larger-room coverage and Wi-Fi or app control. Choose Knka APH4000 if you want lower noise.
Which purifier has higher CADR?
The Alen 45i has a smoke CADR of 255 CFM versus 226 CFM for the Knka APH4000, a difference of 13%.
Which purifier is quieter?
Knka APH4000 is quieter (22 vs 23 dB).
Which purifier covers a larger room?
Alen 45i fits a larger room (about 395 vs 350 sq ft recommended from CADR).
Which purifier has better smart features?
Alen 45i lists Wi-Fi or app control; Knka APH4000 does not.
Which purifier has better filtration?
Both list HEPA filtration.
Bottom line
Choose Alen 45i for higher CADR (255 vs 226 CFM) and larger-room coverage and Wi-Fi or app control. Choose Knka APH4000 if you want lower noise.
| Metric | Alen 45i | Knka APH4000 | Difference / Winner |
|---|---|---|---|
| Smoke CADR | 255 CFM | 226 CFM | Alen 45i (+13%) |
| Recommended room size | 395 sq ft | 350 sq ft | Alen 45i (+13%) |
| Manufacturer claimed coverage | 1900 sq ft | 1695 sq ft | — |
| Minimum noise | 23 dB | 22 dB | Knka APH4000 |
| Filter type | HEPA | HEPA | — |
| Power | — | 45 W | — |
| Wi-Fi / app | Yes | No | — |
| Weight | 14 lb | 9.7 lb | — |