Air purifiers beta · Coway
Owners keep it running in living rooms and dusty workspaces for quiet, steady filtering, though some weigh its purchase and filter costs against cheaper rivals they find work about as well.
Owners who mention its sound find it easy to live with. An owner said even the high setting does not bother them. Only a couple of accounts raise this, too few for the site to give a verdict.
Price comes up against it. An owner who also runs a Levoit found both machines worked about the same and wished they had bought a larger Levoit, given the Airmega's upfront and filter costs. Another now prefers Alen at current Coway prices. This rests on only a couple of accounts, too few for a verdict.
The Coway Airmega 400 is a large floor-standing air purifier with filters on two sides. It is made for big open spaces such as a living room, loft, or open-plan main floor rather than a bedroom. It has an air-quality sensor and automatic modes but no Wi-Fi or phone app.
| Room size | 1,560 sq ft at 2 air changes per hour; 3,120 sq ft at 1 air change per hour |
|---|---|
| CADR | 328 smoke, 328 dust, 400 pollen |
| Filter type | Washable pre-filter plus Max2 filter set (activated carbon + HEPA), two of each |
| Filter life and cost | Max2 filter set about 12 months (tracked by usage, not time); replacement set of two is $129 |
| Noise | 22 to 52 dB(A) |
| Power use | 66 W |
| Warranty | 5 years limited on motor and electronic parts |
From the maker's spec page, checked October 11, 2026. A blank row means the maker does not state it.
A CADR in the low 300s means it can clean the air in a room of about 500 sq ft roughly five times an hour, and the 1,560 sq ft figure is for twice an hour, which is the rate most people want. 22 dB on the lowest setting is quieter than a whisper, so it can run overnight; 52 dB on high is about the level of a quiet conversation. 66 W on high is about what one old-style light bulb uses, so running it all day costs cents, not dollars. Plan on about $129 a year for the two filters, plus rinsing the washable pre-filters yourself.
Pick up to three. You get a page with just those, side by side, on the subjects owners raised.
Once it is set up, the machine itself tends to fade into the background. An owner who bought it for a dusty, unfinished basement workspace, where they had been wearing an N95 mask, still calls it excellent after close to nine years. Another likes the purifier and how it sounds, even on high.
The adjustment is mostly around the edges. The Coway app asks one owner to log in every single time, which they strongly dislike, even though they are happy with the purifier. A very new owner, four days in, with a cat and very high vaulted ceilings, still saw dust on the floor and was not convinced purifiers make much difference. That is an early impression, not a long-term verdict.
The strongest long-term account is a good one: an owner has run it for almost nine years. Their routine is to vacuum the pre-filters monthly, wash them every quarter, and replace the HEPA filters about every 18 months. Filter replacement is a real ongoing cost, and it is part of why some owners look at Levoit or Alen, whose cheaper filters (and, for Alen, a lifetime warranty tied to buying them) appeal to them.
Long-term accounts are thin. The material has one owner reporting years of use and no reports of anything breaking, which is too little to say much about how the Airmega 400 holds up in general. Every theme here rests on too few accounts for the site to give a verdict.
From 2 owner accounts that said how long they have had it. Own one? Add how long yours has lasted.
Nothing with a clear majority yet. Owners who raised these subjects were split, or too few to judge.
Nothing has a clear majority against it yet. Counted from the owners who raised each subject, not from everyone. A subject is judged once at least 4 owners raise it.
5 more subjects came up from fewer than 4 owners each, which is not enough for a fair reading. To see how it stacks up, compare it with another machine.
The same owner, asked again at each point. Fills in as owners answer.
Two questions: how long you have had it, and anything you would like to say about it. Then we ask again as it ages. This helps our mission.
More in air purifiers: Levoit Vital 200s, Levoit 600s.
Among the 2 owner accounts here that gave a duration, 0 described a failure.
Before you buy one used, ask the seller: how old it is, whether it was ever repaired and by whom, and whether any of the parts above have been replaced. Ask to see it run. A receipt tells you the warranty start date; most makers honour the term only for the first owner.
Public discussions we read and summarised in our own words. Nothing here was submitted to Still Kicks.
Counted from public accounts by people who said they own it, and summarised by Still Kicks in its own words. Not a manufacturer claim, a lab test or an estimate.
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