Coway Airmega 400S Review: Is It As Smart As It Claims?


Coway AIRMEGA 400S Review 2019: The Best Air Purifier In The Market Today?

If the air quality in your home is becoming very poor, you may want to invest in an air purifier.  However, air cleaners are not cheap, so it’s important to do your research first before investing in one to ensure you’ll end up with the best and suitable for your needs and budget.

One of the most popular air purifiers today is the Coway Airmega 400S which comes jam-packed with high-tech features and an insatiable appetite for air pollutants. But can it live up to its reputation? And does this smart home appliance really as smart as it claims to be?

On this article, you’ll find out every essential information you need to know about the brand’s latest flagship and air purifiers in general.

About The Airmega 400S Smart Air Purifier

Coway, a company known for manufacturing innovative products including air purifiers with health improvement at its core, developed the Airway 400S. The company is based in Seoul, South Korea, which means that its geographical location makes it in tune with environmental safety and poor air quality problems. They also claim that they have extensive knowledge of the challenges faced by people with respiratory illness and the significance of respiratory health. 

The Airmega 400S is the outcome of many years of comprehensive research and development of the company. The WiFi connected device is designed specifically to handle massive indoor spaces. It’s Alexa-compatible and comes with a wide array of smart options and sensors, including an onboard sensor for air quality. If you live a busy lifestyle, you may find an air cleaner that you can control from a distance quite appealing.

Furthermore, the Airmega 400S features an excellent filter combination that can trap even the smallest of particulates even, a fine control panel, and four fans. It does have a higher price tag compared to others on the market though, but the features and the area it can cover pretty much makes up for it.

Key Features:

  • MAX2 filter which is a combination of Activated Carbon filter and True HEPA filter.
  • It has a 4-stage filtration.
  • 2 permanent washable pre-filter.
  • Air inlet is dual sided.
  • Low, medium, and high settings.
  • The indicator for HEPA filter and Pre-filter is separate, which are based on the environment and real-time use.
  • Adjustable pollutions sensor sensitivity,
  • AUTO, Sleep, and ECO Autonomous Smart modes.
  • An AQ indicator at the front that displays whether air quality is Good, Moderate, Unhealthy, and Very Unhealthy.
  • Timer is built-in
  • Comes with a warranty of 5 years.


  • Large purifying room coverage.
  • Stunning design.
  • Operates quietly.
  • Both sides of the inlet can trap large particles.
  • Excellent technology.
  • Works exceptionally well against smoke and pollutants as small as 0.3 microns.
  • Smart app features and various smart modes.
  • Compatible with Alexa and smartphones.


  • Pricier than most air purifiers.
  • Not intuitive.
  • There are a lot of negative reviews about its app.
  • Filter replacement is expensive even if you only need to change it annually.
  • Remote access is not possible.
  • It doesn’t have an optional ionizer.


The air cleaner is not as sleek as you may want it and with a weigh of 25 lbs, it’s fairly big. Although it has handles, it’s not intended to be moved and carried around your house. But because it covers a wide area, you pretty much don’t need to relocate it.

The front panel has a large bright LED light indicator which tells the measured air quality of its sensors. You can see it even at a distance but can be turned off at night. The entire panel is pretty much straightforward.

The purifier comes with a dual suction operation for collecting air, so it’s not recommended to install it near your walls or somewhere with obstacles. You have to ensure that air will have access to its side panels.

Overall, the design of the Airmega 400S is decent if you’re good with its box-like form. You just have to put it where it will not get in anyone’s way.

How The Airmega 400S Works

How air cleaners work are the same. They suck in and trap particles so that they can’t drift back into your home’s air. However, Coway’s Airmega 400S does have fantastic features that separate it from its competition.

The advanced air purifier can suck in the air from your space on both of its sides. Its series of filters then trap the pollutants inside the air before invigorated, and clean air is blown back to your room out from the unit’s top.

One of the most notable things about the 400S is that it doesn’t generate any ozone since it doesn’t have any negative ion generator.

Filtration System

The unit comes with TrueHEPA filter, activated carbon filter, and washable pre-filters.

  • Pre-Filters. These filters are micro mesh and where particles will first come in contact with. It is designed to weed out dust, dander particles, fur, and hair floating around in your home. The main purpose of these washable filters is to extend the functionality of the HEPA filters by preventing clogging from larger contaminants. It is ideal to clean them twice or at least once a month to prolong its life and ensure efficiency in the performance of your unit.
  • Max2 TrueHEPA Filter Set. The set includes an activated carbon filter and Green TrueHEPA filter. The Green filter can catch up to 99.97% of fumes and all particles from the air in your space, keeping your air free and clean from contaminants such as dust, mold, and pollen. The activated carbon filter, on the other hand, can absorb cooking odors and unpleasant smells.

You need to change these filters every year if your usage is around 8 hours per day. The replacement cost may be higher in comparison to the majority of air cleaners out there but the unit does have a set of 2 filters and services a massive space for which you might need 2 regular air purifiers.

The Airmega 400S has quality indicators, meaning there’s no need to schedule the replacement or cleaning. It will notify you when it’s time to worry about its filters.


The Coway Airmega 400S is worth the investment, especially if you have a large space. The unit has two sets of filters and comes with a wide variety of smart options. It’s also a great choice if you or a family member is prone to asthma and allergies, and wants an air purifier that can revive indoor air well.

About Author

LaDonna Dennis

LaDonna Dennis is the founder and creator of Mom Blog Society. She wears many hats. She is a Homemaker*Blogger*Crafter*Reader*Pinner*Friend*Animal Lover* Former writer of Frost Illustrated and, Cancer...SURVIVOR! LaDonna is happily married to the love of her life, the mother of 3 grown children and "Grams" to 3 grandchildren. She adores animals and has four furbabies: Makia ( a German Shepherd, whose mission in life is to be her attached to her hip) and Hachie, (an OCD Alaskan Malamute, and Akia (An Alaskan Malamute) who is just sweet as can be. And Sassy, a four-month-old German Shepherd who has quickly stolen her heart and become the most precious fur baby of all times. Aside from the humans in her life, LaDonna's fur babies are her world.

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2 years ago

Between leaving behind my family and moving states, being a busy mom and wife, with no support system, being a busy employee, there is no ME TIME. My mom has Stage IV breast cancer, my daughter will be seeing a cardiologist for heart issues, and my recent health scares, I need a slow down, and a pick me up!

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Suji Sanjana
1 year ago

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