Between the Blue Pure 311i+ Max and Airmega 400, the Blue Pure 311i+ Max comes out ahead in several specs, while the Airmega 400 wins on coverage and cadr. Overall, the Blue Pure 311i+ Max scores 61.3 and the Airmega 400 scores 78.3 on our Mars Score.
Which should you buy?
The Airmega 400 is the clear pick on raw spec strength, leading by 17.0 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.
The Blue Pure 311i+ Max doesn't pull ahead on any single popular-comparison spec — its strengths sit in the spec table groups rather than the headline advantages.
Pick the Airmega 400 if you care most about coverage and cadr. Its strongest claims are coverage, cadr, min noise.
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 Blueair - Blue Pure 311i+ Max wins
- No decisive advantages.
Why Coway - Airmega 400 wins
- ▲Coverage — 71.43% more. 60 m² vs 35 m².
- ▲CADR — 41.00% more. 705 m³/h vs 500 m³/h.
- ▲Min noise — 1.00 dB less. 22 vs 23.
Spec comparison
Performance
| Spec | Blueair - Blue Pure 311i+ Max | Coway - Airmega 400 |
|---|---|---|
| CADR | 500 m³/h | 705 m³/hlead |
| Coverage | 35 m² | 60 m²lead |
| True HEPA H13+ | true | true |
| Activated carbon | true | true |
Smart & Noise
| Spec | Blueair - Blue Pure 311i+ Max | Coway - Airmega 400 |
|---|---|---|
| Min noise | 23 dB | 22 dBlead |
| Air quality sensor | true | true |
| Smart app | true | true |
Frequently asked
Spec-level deep dives
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