The Coway Airmega 400 stands out with its user-friendly interface and extensive controls compared to other purifiers. It is engineered to filter large volumes of air without excessive noise, making it ideal for achieving performance and comfort in one package. The smart mode utilizes an air quality sensor to automatically adjust operation based on detected pollution levels.

Coway Airmega 400
Coway Airmega 400

Key Features and Capabilities

The Airmega 400 shines when purifying the air in big rooms or open floor plans. It provides both manual on-unit controls and app connectivity for monitoring and managing air cleansing. The built-in sensor enables the intelligent auto mode to tweak fan speeds according to real-time indoor air quality data. Its high-end HEPA filter ranks among the best for removing airborne particles like dust, pollen, and smoke.

Ideal Usage Scenarios

  • Large living spaces up to 1,560 square feet
  • Open floor plan homes and apartments
  • Bedrooms, basements, living rooms
  • Accommodating households with members having special air quality needs

Standout Features

  • Wide range of fan speeds: Sleep, Low, Medium, High, Turbo
  • Real-time air quality monitoring with Auto mode
  • Pollution sensor tracks PM1.0, PM2.5, and PM10 particulates
  • Filter replacement indicator light
  • Whisper-quiet operation: 22 dB on lowest setting
  • App and Alexa voice controls

Air Filtration Performance

  • True HEPA filter captures 99.97% of particles 0.3 microns
  • Activated carbon layer traps odors, gases, and VOCs
  • Pre-filter collects large particles like hair and dander

CADR Ratings

  • Dust: 400 m3/h | Smoke: 400 m3/h | Pollen: 400 m3/h


  • Excels in extra large spaces up to 1,560 sq ft
  • Loaded with speed/mode controls
  • Very quiet even on higher fan settings
  • Top-tier air cleaning performance
  • Real-time air quality monitoring


  • Expensive initial cost and filter replacements
  • Bulky unit takes up significant floor space
  • App connectivity can be glitchy

Hands-On Reviews from Actual Owners

Numerous reviewers praise the Airmega 400’s purification abilities in big areas and quiet operation relative to its power. Users appreciate the range of settings and auto mode for effortless maintenance of healthy indoor air. Some felt the unit takes up too much space and drains energy. Connectivity issues with the app have also been cited as an inconvenience by a few owners.

“Our large open floor plan is kept amazingly clean now. Set it to auto mode and forget it – so quiet too!”

“I have breathing issues but can finally use my basement with this thing running, it’s a game changer.”

“It’s kind of massive and my toddler keeps trying to play with it. Works great though once I hid the controls.”

“The replacement filters are pricey but worth it to me for cleaner air – just wish the app worked better.”

How It Compares to Similar Models

The flagship Coway Airmega 400S surpasses its predecessor 400 as well as competitors like the Winix 5500-2, Coway 1512HH Mighty, and Levoit Core 400S in terms of raw air cleansing competence. It moves more air over a larger coverage area while maintaining lower noise levels. The operating cost is a drawback though, with filters needing regular changes.

Coway Airmega 400 vs 400S

The nearly identical 400S model adds WiFi and app controls for monitoring air quality and managing device settings remotely. It costs around $50 more upfront but otherwise performs the same.

Coway Airmega 400 vs Winix 5500-2

The Winix struggles to match the 400’s cleansing power and noise reduction. It also lacks an auto mode and covers less ground at just 1,300 sq ft. However, filter replacements are cheaper.

Coway Airmega 400 vs Coway AP-1512HH Mighty

While very competent for small and mid-sized rooms, the Mighty simply can’t keep up with the Airmega 400 in terms of power and coverage. It also omits extras like auto mode and pollution sensors.

Coway Airmega 400 vs Levoit Core 400S

Levoit’s 400S delivers similar CADR ratings to the Airmega 400 but serves smaller spaces of just 1,000 sq ft. An auto mode is included but air quality data isn’t displayed like Coway’s model.


The Coway Airmega 400 justifies its steep price tag by delivering exceptional air cleansing to extra large rooms with relatively hushed performance. Between the manual on-unit controls and app connectivity, operating the device is simple enough for any user. The addition of auto mode and air quality tracking capabilities make maintaining a healthy indoor environment effortless. Just keep in mind the recurring filter replacement costs.

For house hunters prioritizing cleaner indoor air and quiet operation in their next home, the Airmega 400 is a premier solution worth the investment. Even residents of older houses with dust issues may find this unit can adequately filter common allergens and particles when run regularly. Ultimately the combination of purification competence, intuitive controls, and silent airflow make the Coway Airmega 400 a leading choice for critical consumers.


Hey there, I'm Kevin, editor of Xievo. I'm passionate about air purifiers and providing accurate information to help readers make informed decisions. In my free time, I love hiking and experimenting with air purifiers in my own home. Thanks for visiting Xievo!

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