Between the Airmega 400 and C909, the Airmega 400 comes out ahead in cadr and coverage, while the C909 wins on several specs. Overall, the Airmega 400 scores 78.3 and the C909 scores 66.8 on our Mars Score.
Which should you buy?
The Airmega 400 is the clear pick on raw spec strength, leading by 11.5 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the Airmega 400 if you care most about cadr and coverage. The biggest gaps in its favor are cadr, coverage, min noise.
The C909 similarly doesn't carry a headline advantage on the popular specs — look at the full table for category-specific deltas.
Both ship with comparable true hepa h13+, activated carbon, so those specs don't separate the two — focus on the differences below.
Bottom line: the Airmega 400 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Coway - Airmega 400 wins
- ▲CADR — 41.00% more. 705 m³/h vs 500 m³/h.
- ▲Coverage — 20.00% more. 60 m² vs 50 m².
- ▲Min noise — 5.00 dB less. 22 vs 27.
Why Winix - C909 wins
- No decisive advantages.
Spec comparison
Performance
| Spec | Coway - Airmega 400 | Winix - C909 |
|---|---|---|
| CADR | 705 m³/hlead | 500 m³/h |
| Coverage | 60 m²lead | 50 m² |
| True HEPA H13+ | true | true |
| Activated carbon | true | true |
Smart & Noise
| Spec | Coway - Airmega 400 | Winix - C909 |
|---|---|---|
| Min noise | 22 dBlead | 27 dB |
| Air quality sensor | true | true |
| Smart app | true | true |
Frequently asked
Spec-level deep dives
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