Coway Airmega 350
#11 in Large roomsFull review
For big rooms where you want high certified airflow and low running costs without app features.
Amazon $339$339
The Coway Airmega 350 and the Alen BreatheSmart 75i are evenly matched, rated 3.4 and 3.3. The Coway Airmega 350 leads on value. The Alen BreatheSmart 75i wins on quiet and auto mode. The Coway Airmega 350 costs $360.59 less ($339 vs $699.59).
Alen BreatheSmart 75i
#12 in Large roomsFull review
A premium large-room purifier with long-lasting filters, for buyers willing to pay for quiet and a subscription-backed guarantee.
Amazon $699.59$699.59
Prices were last checked October 22, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Coway Airmega 350 for value ($0.94 per cfm of smoke CADR vs $1.89 per cfm of smoke CADR).
- Choose the Alen BreatheSmart 75i for quiet (51 dB at top speed (maker rating) vs 54.7 dB at top speed (maker rating)) and auto mode (particle sensor and Wi-Fi app vs PM laser sensor, auto mode).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every large rooms air purifier; a clear win is highlighted. How we rank explains each one.
| Factor weight | Coway Airmega 350 | Alen BreatheSmart 75i |
|---|---|---|
| Overall rating | 3.4/5 | 3.3/5 |
| Value 25% | 57 $0.94 per cfm of smoke CADR | 0 $1.89 per cfm of smoke CADR |
| Filter cost 20% | 83 $79 a year in filters | 76 $99 a year in filters |
| Quiet 20% | 35 54.7 dB at top speed (maker rating) | 60 51 dB at top speed (maker rating) |
| Efficiency 15% | 54 6.3 cfm per watt | 61 6.9 cfm per watt |
| Auto mode 10% | 70 PM laser sensor, auto mode | 100 particle sensor and Wi-Fi app |
| Warranty 10% | 0 1-year warranty | 50 warranty not published (neutral score used) |
Specifications
| Coway Airmega 350 | Alen BreatheSmart 75i | |
|---|---|---|
| Performance | ||
| Smoke CADR | 360 cfm | 370 cfm |
| Dust CADR | 378 cfm | 351 cfm |
| Pollen CADR | 450 cfm | 431 cfm |
| PM2.5 CADR | 369 cfm | 360 cfm |
| CADR certified by | ENERGY STAR | ENERGY STAR |
| Room size (AHAM) | 558 sq ft | 574 sq ft |
| Coverage (maker) | 2,640 sq ft | 2,800 sq ft |
| Noise | 21.5 to 54.7 dB | 25 to 51 dB |
| Efficiency | ||
| Efficiency (IEF) | 6.3 cfm/W | 6.9 cfm/W |
| ENERGY STAR | Yes | Yes |
| Energy use | 344 kWh/year | 304 kWh/year |
| Power at top speed | 62 W | 55 W |
| Filters | ||
| Filter | HEPA | HEPA (Essential/Pure filter as sold in this listing) |
| Activated carbon | Yes | No |
| Replacement | Airmega 350 Fresh Starter Plus filter | Essential (Pure), formerly B7 |
| Replacement cost | $79 every 12 months | $99 every 12 months |
| Yearly filter cost | $79/year | $99/year |
| Ionizer | No | Yes, can be switched off |
| CARB certified (ozone) | Yes | Yes |
| Controls and build | ||
| Air-quality sensor | PM laser | particle |
| Auto mode | Yes | Yes |
| Wi-Fi app | No | Yes |
| Fan speeds | 3 | 5 |
| Dimensions | 23.2 x 12.0 x 12.0 in | 27 x 18.5 x 11.5 in |
| Weight | 17.2 lb | 27 lb |
| Warranty | 1 years | - |