Our verdict
Pick the Coway Airmega 400 if you want the lower price. Pick the Coway Airmega 400S if it is the cheaper of the two on the day you buy.
The central trade-off
Filters. Coway Airmega 400: HEPA.
Filters. Coway Airmega 400S: HEPA.
Price. When we checked, the Coway Airmega 400 listed for less ($649 against $749); prices move, so check both buttons.
Side by side
| Specification | Coway Airmega 400 | Coway Airmega 400S |
|---|---|---|
| Rated room size | 3,120 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 | 22 dB | Not stated by the maker |
| Power draw | 66 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.