Product Review · Air Purifiers · #10 Ranked
Coway Airmega 400
Air purifiers — large-room dual-filter HEPA · Reviewed by Katie · amazon.com live, Sept 28 2026
Why it scored a 76
At $369.49 the Coway Airmega 400 is a large-room True HEPA purifier with dual side-intake Max2 filters, long Wirecutter's large-space pick. Quality leads at 90 and Reliability at 90: 328 CFM of smoke CADR covers 1,560 sq ft at 2 ACH, low speed stays near 22 dB, the pre-filters wash, and the 5-year warranty is the longest here after Alen. Value drags at 55 because it usually sells for $350–$450, well below this listing, and Features at 55 since the 2016 design has no app (the 400S adds it), and cannot sit flush against a wall. It is for a big open-plan space, bought on a real discount.
What you're getting
- AHAM CADR 328 smoke / 328 dust / 400 pollen CFM, dual side-intake Max2 filters
- 1,560 sq ft at 2 ACH; 3,120 sq ft at 1 ACH
- 22-52 dB(A) across 4 fan speeds; whisper-quiet on low
- Two Max2 HEPA + carbon filters: ~$80-90/yr, 6-12 month life; washable pre-filters
- 66 W max; 24.7 lb; 14.8 x 22.8 x 14.8 in square body, cannot sit flush to a wall
- Particle sensor, AQI LED ring, auto/eco/sleep modes, 1/4/8-hr timer
- No app or Wi-Fi (the 400S adds it); 2016 design
- 5-year warranty, longest here after Alen
ViperScore breakdown
At a glance
- AHAM CADR 328 smoke / 328 dust / 400 pollen CFM
- 1,560 sq ft at 2 ACH; 22–52 dB across 4 speeds
- Two Max2 filters ~$80–90/yr; 5-year warranty
- Price$369.49
- TierAir purifiers — large-room dual-filter HEPA
- Category rank#10 of 10
Should you buy the Coway Airmega 400?
The Coway Airmega 400 is the large-room purifier for an open-plan main floor or a big master suite, where you need 328 to 400 CFM of CADR from a single unit. Two Max2 HEPA and carbon filters draw from both sides, and Coway backs it with a 5-year warranty. It ranks tenth of ten in our air purifier group, but that says more about price than performance: at $369.49 it is the most expensive unit here by a wide margin. If your room is under 450 sq ft, the Blueair 311i Max delivers similar CADR for about a third of the money.
Where it earns its score
- Big-room CADR. AHAM CADR of 328 smoke / 328 dust / 400 pollen CFM from dual side-intake filters, rated for 1,560 sq ft at 2 air changes per hour.
- Quiet for its size. 22 to 52 dB(A) across four fan speeds, and genuinely quiet on low.
- Longest warranty short of Alen. Five years of Coway coverage, with Quality and Reliability both scoring 90.
- Reasonable filter cost. The two Max2 filters run about $80 to $90 a year, with washable pre-filters.
What to know first
- Value is the lowest factor at 55. The price has drifted well above the $400 range this model is usually found at; if you see it lower, the math changes.
- It is a big square box. 24.7 lb, 14.8 x 22.8 x 14.8 in, and because both sides are intakes it cannot sit flush against a wall.
- No app or Wi-Fi. This is a 2016 design; the 400S adds connectivity. Features scores 55.
- Two filters to replace. Each side has its own Max2 filter with a 6 to 12 month life.
Our verdict
The Coway Airmega 400 scores 76, Fair Buy. It is a durable, quiet, well-warranted large-room purifier that is currently priced too high to recommend over smaller alternatives. Buy it only if you need one unit for 1,000-plus sq ft; otherwise the Levoit Core 400S or Blueair 311i Max will cover a normal room for far less.
Levoit Core 400S
Questions buyers ask
What size room is the Coway Airmega 400 for?
Coway rates it for 1,560 sq ft at 2 air changes per hour, or 3,120 sq ft at a single air change, making it a whole-floor unit.
Does the Coway Airmega 400 have Wi-Fi?
No. The standard 400 has no app or Wi-Fi. The Airmega 400S is the connected version.
How much are Coway Airmega 400 replacement filters?
The two Max2 HEPA and carbon filters cost roughly $80 to $90 a year combined and last 6 to 12 months each.
Ready to check it out?
Coway Airmega 400 · ViperScore 76 · Fair Buy · $369.49
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