Our verdict
Pick the Coway Airmega 400S if running cost matters. Pick the Coway Airmega 450 if your room is larger and you want the lower price.
The central trade-off
Rated room size. Coway Airmega 450: 3,285 sq ft; Coway Airmega 400S: 3,120 sq ft.
Smoke CADR. Coway Airmega 450 states 439 CFM; the other's maker page doesn't.
Power draw. Coway Airmega 400S: 66 W; Coway Airmega 450: 72 W.
Filters. Coway Airmega 400S: HEPA.
Filters. Coway Airmega 450: HEPA.
Price. When we checked, the Coway Airmega 450 listed for less ($499 against $749); prices move, so check both buttons.
Side by side
| Specification | Coway Airmega 400S | Coway Airmega 450 |
|---|---|---|
| Rated room size | 3,120 sq ft | 3,285 sq ft |
| Smoke CADR | Not stated by the maker | 439 CFM |
| 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 | 23.7 dB |
| Power draw | 66 W | 72 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.