Choose Alen 45i for lower noise.
Which purifier has higher CADR?
The Alen 45i has a smoke CADR of 255 CFM versus 252 CFM for the Winix 5520, a difference of 1%.
Which purifier is quieter?
Alen 45i is quieter (23 vs 40 dB).
Which purifier covers a larger room?
Alen 45i fits a larger room (about 395 vs 391 sq ft recommended from CADR).
Which purifier has better smart features?
Both list smart features (True HEPA filtration, Whisper-quiet operation, Smart Sensor, Auto Mode vs 4‑Stage filtration, Wi‑Fi & Alexa control, True HEPA filter, AOC™ carbon filter).
Which purifier has better filtration?
Alen 45i lists HEPA; Winix 5520 lists True HEPA, AOC™ Carbon.
Bottom line
Choose Alen 45i for lower noise.
| Metric | Alen 45i | Winix 5520 | Difference / Winner |
|---|---|---|---|
| Smoke CADR | 255 CFM | 252 CFM | Alen 45i (+1%) |
| Recommended room size | 395 sq ft | 391 sq ft | Alen 45i (+1%) |
| Manufacturer claimed coverage | 1900 sq ft | 1882 sq ft | — |
| Minimum noise | 23 dB | 40 dB | Alen 45i |
| Filter type | HEPA | True HEPA, AOC™ Carbon | — |
| Power | — | 50 W | — |
| Wi-Fi / app | Yes | Yes | — |
| Dimensions | — | 13.59 × 8.27 × 22.17 in | — |
| Weight | 14 lb | 13.3 lb | — |