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Coway Airmega 400S

Ranked #7 of 20 in Best Large-Room Air Purifiers: Coway, Blueair, Levoit, Winix, IQAir & More (2026). Here is every spec we scored, where it came from, and how it compares.

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#7

Coway Airmega 400S

Best for: Coway's large-room classic with app control

4.8/10

What we like

  • 328 CFM smoke CADR
  • App with scheduling

Watch out for

  • 24.7 lb

Score breakdown

Smoke CADR 40%
CADR per watt 15%
Quietest setting 10%
Loudest setting 10%
Carbon or odor stage included 10%
Main filter life 15%
Smoke CADR328 CFM
CADR per watt5 CFM/W
Quietest setting22 dB
Loudest setting52 dB
Carbon or odor stage includedYes
Main filter life12 months
CADR (smoke / dust / pollen)328 / 328 / 400
Coverage3,120 ft² at 1 air change/hr; 1,560 ft² at 2
FilterWashable pre-filter + Max2 set (activated carbon + HEPA)
Filter lifeMax2: 1 year
Noise22–52 dB(A)
Power66 W
AppIoCare+ app, scheduler
Weight24.7 lb
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Specs source:

Coway Airmega 400S head-to-head

Head-to-headBlueair Classic Pro CP7i vs Coway Airmega 400SHead-to-headCoway Airmega 400S vs Levoit EverestAirHead-to-headCoway Airmega 400S vs Molekule PECOAir+ Featured inBest Air Purifiers for Open-Plan Living Spaces (2026)

How it compares

Open the full comparison table

Coway Airmega ProX
8.3/10
#1 · The most clean air of any purifier here
Blueair Blue Signature
7.3/10
#2 · 455 CFM from a 13.2 lb side-outlet unit
Winix XQ
6.0/10
#3 · Winix's dual-filter large-room model, 461 CFM smoke
Blueair Blue Signature SP3i
5.7/10
#4 · The mid-size Signature, 321 CFM
Blueair Classic Pro CP7i
5.7/10
#5 · A two-filter, 393 CFM unit
Blueair Blue Pure 311i+ Max
5.6/10
#6 · 339 CFM at 7.9 lb
Rabbit Air A3
4.8/10
#8 · A wall-mountable purifier with a custom filter slot
Coway Airmega 300
4.2/10
#9 · The 400's smaller sibling, without an app
Levoit Core 400S
3.8/10
#10 · A cylinder purifier with 231 CFM at 38 W
Levoit EverestAir
3.8/10
#11 · Levoit's 354 CFM purifier with adjustable vents
Levoit Vital 200S
3.6/10
#12 · A 250 CFM purifier with a pet mode
Winix AT40
3.5/10
#13 · An Energy Star 265 CFM purifier
Winix T810
3.5/10
#14 · A 272 CFM tower with a numeric air display
Shark BreatheClear MAX (HP362)
3.5/10
#15 · Shark's biggest purifier, with up to 6 years before a filter change
Coway Airmega 250S
3.4/10
#16 · A slim, wall-friendly 249 CFM purifier
Shark NeverChange Air Purifier MAX (HP302)
2.3/10
#17 · A 5-year-filter purifier for up to 1,400 sq ft
IQAir Atem X
2.1/10
#18 · IQAir's large round purifier, 15 dB on low
Honeywell InSight HPA5300
2.1/10
#19 · Three HEPA filters for a 500 sq ft room
Molekule PECOAir+
2.0/10
#20 · PECO + HEPA filtration with CO2 and TVOC sensors