Coway Airmega 400 vs Dyson Purifier Big Quiet Formaldehyde
We compare the Coway Airmega 400 and Dyson Purifier Big Quiet Formaldehyde head-to-head on performance, features, value, and more. Here's which one wins.
Coway Airmega 400
Scored 9/10 in our testing
Coway Airmega 400
Large living spaces up to 1,560 sq ft needing powerful, efficient air purification
Dyson Purifier Big Quiet Formaldehyde
Design-conscious buyers who want the quietest large-room purifier with formaldehyde destruction
Score Breakdown
| Coway Airmega 400 | Category | Dyson Purifier Big Quiet Formaldehyde |
|---|---|---|
| 9.5/10 ✓ | Performance | 9.3/10 |
| 8.5/10 | Features | ✓ 9.5/10 |
| 9/10 ✓ | Ease of Use | 8.8/10 |
| 9/10 ✓ | Value | 7/10 |
| 9/10 ✓ | Overall | 8.7/10 |
Specs Comparison
| Coway Airmega 400 | Spec | Dyson Purifier Big Quiet Formaldehyde |
|---|---|---|
| Up to 1,560 sq ft | Coverage | Up to 1,076 sq ft |
| True HEPA + activated carbon | Filtration | HEPA H13 + catalytic formaldehyde filter |
| 350 CFM (smoke) | CADR | As low as 15 dB |
| 22-52 dB | Noise | Dyson Link app, air quality display |
| ~12 months | Filter Life | PM2.5, PM10, VOCs, NO2, formaldehyde |
Coway Airmega 400
Pros
- + Massive 1,560 sq ft coverage
- + Dual-sided HEPA filtration
- + Real-time air quality display
- + Quiet at lower speeds
Cons
- − Large footprint
- − No app control without Airmega AP model
- − Replacement filters add ongoing cost
Dyson Purifier Big Quiet Formaldehyde
Pros
- + Near-silent operation at 15 dB
- + Catalytic formaldehyde destruction
- + Comprehensive sensor array
- + Stunning industrial design
Cons
- − Very expensive
- − Large footprint
- − Dyson filter replacements are costly
Our Verdict
Based on our scoring, the Coway Airmega 400 comes out on top with an overall score of 9/10. The Coway Airmega 400 is the gold standard for large-room air purification. Dual HEPA filters pull air from both sides simultaneously, cleaning a massive 1,560 sq ft space efficiently. The real-time air quality indicator and auto mode adjust fan speed intelligently. Replacement filters are reasonably priced for the coverage area.
Buy the Coway Airmega 400 on AmazonRead the full Best Air Purifiers for Large Rooms 2026 guide for complete reviews of all 5 products.