Coway Airmega 400 Smart Review

Air Purifier
The most advanced air purifier intelligently, efficiently & quietly cleans the air in your home. It features the dual-filtration system that eliminates 99.97% of particulate matter from the atmosphere, while the accompanying pollution1 indicator enables you to effortlessly monitor & manage air quality in real-time.
Coway Airmega 400 Smart

Review Feature Summary

  • Air Quality Monitoring
  • Smart Technology
  • Powerful Dual Suction
* On special until end August 2020

Coway Airmega 400 Smart Air Purifier

Mark Johnson
Mark Johnson
Air Quality Expert
Last Updated:  Aug, 2020
Rated from 9456 reviews.

I think you’ll agree with me when I say:

It’s REALLY hard to choose an air purifier with all the options available!

Or is it?

Well, it turns out, that after years and hundreds of hours of testing & reviewing, we have strong opinions about what makes the best air filtration system: level of purification, efficiency, and maintenance.

The Coway Airmega 400 Smart (On special until end Aug, 2020) has all the qualities and features, giving it an added advantage and an edge over its competitors.

Quick Summary of the Coway Airmega 400 Smart

Coway Airmega 400 is designed to accommodate room sizes up to 1,560 square feet and it cleans the air two times in one hour. Airmega Max2 filter – combined activated carbon and True HEPA filter – captures and reduces up to 99.97% of particles 0.3 microns in the air, including pollen, pollutants and other allergens. It also reduces more than 99% of volatile organic compounds and reduces fumes such as NH3 and CH3CHO. It also includes washable and permanent pre-filter to catch larger dust particles.

The Good & the Bad


  • Easy to Clean & Use
  • Whisper-Quiet
  • Durable & Functional


  • The air purifier is pricey, but it’s worth every penny.

Key Features

  • Air Quality Monitoring – It communicates indoor air quality in real-time. The brightly colored LED ring3 lets you know how clean or dirty your indoor air is every minute of the day.
  • Smart Technology – It automatically adapts to its surroundings by adjusting fan speeds based on the room’s air quality. That means your unit is energy efficient without compromising efficacy.
  • Powerful Dual Suction – Coway Airmega draws contaminated air from two sides and pushes filtered air out the top of the unit, cleaning the air efficiently.
  • Max2 Filter Combined with theactivated carbon & True HEPA filter, it helps in getting rid of up to 99.97 percent of particles 0.3 microns in the air, including pollen, pollutants & other allergens.
  • Filter Indicator – Informs you when the two Max2 filters need to be replaced.

What's Included?

Here's what you get when you buy this Air Purifier:

  • 1-Year Warranty
  • Filter Indicator
  • Pre-filter
  • Max2 Filter
  • Powerful Dual Suction

Common Questions

  • How loud is the Coway Airmega 400 Smart filter at regular (not night) volume?

It really is not that loud! Regular volume is varied from step 1, 2, 3. You really can't hear anything at 1, and 2, is quiet too. Once it's 3, and the lights turn redish or dark pink, it does start to sound a bit louder.

  • How do you clean the Coway AirMega 400 Smart Air Purifier?

You can clean the pre-filters manually, but you should replace the HEPA fitler2 at least once every year. .

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Do Air Purifiers Work?

Our Verdict

Coway Airmega air purifiers are designed to ensure your indoor air is cleaner. We would recommend this product for use in big rooms taking full advantage of its silent mode.

What to Look for in a New Air Purifier?

If you’re in the market for a new Air Purifier, you’re probably looking at the different options and wondering which is the best one to choose.

Don’t worry, we’ve got you covered. Our reviews are based on the following features:


Only the most effective purifiers make the cut.

Noise Level

So there's more clean air and less noise.


Because you need a machine that’s built to last.

Ease of Use

It needs to be easy to use and easy to clean.


The Top Air Purifiers We've Reviewed


IQAir Health Pro Plus

Our Rating: 9.2/10

IQAir Health Pro Plus​


Rabbit Air A2

Our Rating: 9.4/10

RabbitAir MinusA2​



Our Rating: 9.0/10

Winix 5500-2


Honeywell 50250

Our Rating: 8.6/10

Honeywell 50250-S

Have you read our article on the air purifiers?

Or our article on the the best mold air purifiers review?

Mark Johnson

Mark Johnson

Mark advises business, individuals, and organizations on how to use and get the best purifiers so as to maintain their offices and homes. For a fresher and cleaner environment, he is the man for you. He loves ideas and concepts and uses his skills to make them a reality.

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