Short answer: the Airmega 400 is a large-room air purifier with a smoke CADR of 328, a washable pre-filter, and a combined carbon and HEPA filter set. Coway rates it for 1,560 sq ft. We couldn’t confirm a price for the base model, so check the listing.
How big a room does it cover?
Run the numbers. CADR is the volume of cleaned air the unit delivers, in cubic feet per minute. A smoke CADR of 328 is 19,680 cubic feet per hour.
- In a room with an 8 ft ceiling, 5 air changes per hour works out to about 490 sq ft.
- At 2 air changes per hour, the same CADR covers about 1,230 sq ft.
Coway’s 1,560 sq ft figure is at 2 air changes per hour, which is the optimistic end. For a bedroom, a home gym, or a room with a sauna in it, I’d size by the 5-changes figure. That makes this a purifier for a large living room, not a whole floor.
How loud is it?
The listed range is 22 to 52 dB(A). The low end is close to silent. The top speed is a little quieter than normal conversation. Auto mode moves between them based on the air quality sensor, so it is quiet most of the time.
What does it cost to keep running?
The pre-filter is washable. The Max2 filter set (activated carbon plus HEPA) is rated for 1 year. Our data has no replacement filter price. Look it up before you buy, because the filter is the main ongoing cost of any purifier.
Where does it go?
It is 14.8” square and 22.8” tall, and weighs 24.7 lbs. Leave open space around the intake sides. It plugs into a household outlet.
Here’s what the spec sheet won’t tell you
The base 400 has no Wi-Fi or app. That is the separate 400S model, which has a different price. Make sure the listing you buy matches the model you want. Warranty terms aren’t in our data.
How it compares
This is the only air purifier we list, so there is no direct rival on this site. For how we assess this category, see the Home Wellness Equipment Guide.
