Our verdict
Pick the Coway Airmega 300 if running cost matters and you want the lower price. Pick the Coway Airmega 400 if your room is larger.
The central trade-off
Rated room size. Coway Airmega 400: 3,120 sq ft; Coway Airmega 300: 2,513 sq ft.
Power draw. Coway Airmega 300: 57 W; Coway Airmega 400: 66 W.
Filters. Coway Airmega 300: HEPA.
Filters. Coway Airmega 400: HEPA.
Price. When we checked, the Coway Airmega 300 listed for less ($549 against $649); prices move, so check both buttons.
Side by side
| Specification | Coway Airmega 300 | Coway Airmega 400 |
|---|---|---|
| Rated room size | 2,513 sq ft | 3,120 sq ft |
| Smoke CADR | Not stated by the maker | Not stated by the maker |
| CADR | Not stated by the maker | Not stated by the maker |
| Quietest setting | Not stated by the maker | Not stated by the maker |
| Noise | Not stated by the maker | 22 dB |
| Power draw | 57 W | 66 W |
| Filters | HEPA | HEPA |
| Warranty | Not stated by the maker | Not stated by the maker |
Values are the makers' published specifications. "Not stated" means the maker doesn't publish it.