AirDoctor AD4000 vs Coway Airmega 400
A spec-only comparison using ENERGY STAR certification data. We have not tested either unit, and features like noise, filter price and build quality are not covered here.
- Cleaning speed: the Coway Airmega 400 has the higher smoke CADR (376 vs 370 cfm, 2% more).
- Running cost: the Coway Airmega 400 uses less electricity per ENERGY STAR (366 kWh/yr), about $5.53/yr less at the U.S. average rate (estimate).
- Room size: by AHAM's 2/3 rule, up to about 555 sq ft vs 564 sq ft.
Both sit in ENERGY STAR data as Extra-large rooms (350+ cfm) units by smoke CADR. Listed differences: only the Coway Airmega 400 lists an air-quality-sensor auto mode; reported ozone is 1 ppb vs 0 ppb. Over 5 years at the U.S. average rate, the electricity difference is about $27.65 (estimate).
| AirDoctor AD4000 | Coway Airmega 400 | |
|---|---|---|
| Smoke CADR (cfm) | 370 | 376 |
| Dust CADR (cfm) | 393 | 384 |
| Pollen CADR (cfm) | 450 | 409 |
| ENERGY STAR room size | 574 sq ft | 583 sq ft |
| AHAM 2/3-rule room size | 555 sq ft | 564 sq ft |
| Annual energy | 396.2 kWh | 366 kWh |
| Est. electricity/yr (U.S. avg) | $72.54 | $67.01 |
| Smoke CADR per watt | 5.49 | 6.02 |
| Ozone (reported) | 1 ppb | 0 ppb |
| Technology | — | Fan and Filter |
| Filters listed | HEPA-Type | Composite Filter, Composite Filter |
| Auto mode | None | Air Quality Sensor |
| Connected | No | No |
| Most Efficient | No | No |
| Source | ENERGY STAR record 4518215 | ENERGY STAR record 4512744 |
Purchase price and filter cost are not included (data gap). Electricity estimates use 18.31¢/kWh (EIA).
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See AirDoctor air purifiers on the manufacturer's site (plain link, not an affiliate link)
See Coway air purifiers on the manufacturer's site (plain link, not an affiliate link)