Our verdict
Pick the Coway Airmega ProX if it is the cheaper of the two on the day you buy. Pick the Coway Airmega 400 if you want the lower price.
The central trade-off
Rated room size. Coway Airmega 400 states 3,120 sq ft; the other's maker page doesn't.
Filters. Coway Airmega ProX: HEPA.
Filters. Coway Airmega 400: HEPA.
Price. When we checked, the Coway Airmega 400 listed for less ($649 against $999); prices move, so check both buttons.
Side by side
| Specification | Coway Airmega ProX | Coway Airmega 400 |
|---|---|---|
| Rated room size | Not stated by the maker | 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 | 65 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.