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coway airmega 400 product

The Coway Airmega 400 is what you’d call an industrial air purifier in a small footprint. Going by the manufacturer’s claims, this air purifier is potent to handle spaces of up to 1560 sq. ft. So, if you are looking for a powerful unit for your large indoors, this purifier could be it.

Before adding it to the cart, though, let’s give you an insight of how it performs in an uncontrolled environment. 

Coway Airmega 400 is Best For:

  • Homeowners with large indoor spaces– the Airmega 400 offers a wide coverage of 1560 sq.ft. This makes it ideal for large living rooms, bedrooms, and basements.
  • Those having problems with Volatile Organic Compounds– Activated Charcoal filters on this unit promises to remove up to 99% of VOCs.
  • Anyone looking for a powerful yet quiet air purifier– this model has a noise range of 22-52 dB.
  • Homeowners who prefer a non-ionizing air purifier– the Airmega 400 does not use an ionizer to eliminate harmful air pollutants.

Assembly and Set up

This device does not require any form of assembly. All the parts come already fitted, including the filters. You’ll need to open the side panels and remove the plastic cover on the filtration kits, though. This is done to prevent the screens from collecting dust during storage and shipping.

This process takes only a few minutes and does not require any tool. If anything, it offers you an opportunity to start familiarizing yourself with the air purifier right out of the box.

Construction Design and Quality

In our opinion, the Coway Airmega 400 seems to have been built with homes in mind. Its incredible balance of technology and performance offers you a model that cleans the air without being an eyesore to your indoor spaces. On this note, you can get this air purifier in white or graphite/silver- whichever color that complements your interior décor the best.

Its shell is made of thick plastics, and all the parts fit seamlessly. Basically, this is a unit that we expect to offer excellent value in terms of durability- of course, with proper care.

coway airmega 400 living room

Size, Weight, and Placement

This air purifier maxes out at 14.8’’ by 14.8’’ by 22.8’’. In all honesty, we wouldn’t call it a compact unit. However, its sleek and clean design gives it an incredible appearance wherever it is placed.

The Airmega 400 is meant to stay on the floor- just as its 4 sturdy legs depict. Thanks to its 2-directional air intake principle, you’ll have a lot of options in terms of the best position for locating it.

You can place it along the wall, next to a couch, and even at the center of the room. Importantly, remember not to put it too close to objects that would obstruct air intake through the side panels.

Lastly, this air purifier weighs around 24.7 lbs. Although it’s relatively on the heavier side, this weight is within the acceptable range for an air purifier that is designed to cover large rooms. 

On the same note, we appreciate that Coway cared to include some sturdy handles on the side. These will come in handy should you want to move it between rooms.

coway airmega in hallway 1

We reviewed how the Coway Airmega 400 works

This model uses the same concept that most air purifiers use: sucking contaminated air through a series of filters and ejecting purified air.

As mentioned before, Airmega 400 uses 2 filtration kits. Each of these filtration kits consists of;

  • Pre-filter– this is a washable preliminary screen that traps large contaminants, including pet fur and hair. Removing these pollutants ensures that the subsequent filters work at their optimum level since they are not overburdened by large stuff.
  • Max2 filter– this is a combination of 2 air filtration technologies; True-HEPA and an Activated Charcoal filter.

A True-HEPA (High-Efficiency Particulate Air) filter is one that has been tested and proven to remove 99.97% of air contaminants, measuring 0.3 microns. This filter removes dust and dust mites, pollen, pet dander, and bacteria, among other pollutants.

The Activated Charcoal filter has millions of active sites that trap most household odors, smoke, and VOCs.

Controls and Special Modes Review

The Coway Airmega 400 can only be operated from its control interface. It does not come with a remote control or an App.

This is one of its most significant drawbacks for some people. However, if you consider an air purifier as a set-and-forget device, this might not be a deal-breaker.

If anything, the control interface has all the functions you’d expect on a mid-budget air purifier, including a timer, an auto mode, and a sleep mode.

An exciting feature that caught our attention here is the pre-wash button. This button will light up to alert you on the need to clean the pre-filters at 6 stages; 100%, 80%, 60%, 49%, 20%, and 0%.

We also appreciate the light sensor that switches all the lights to sleep mode after detecting darkness for around 3 continuous minutes.

This air purifier’s Smart (auto) function engages yet another interesting mode that we don’t often see: Eco mode. This is a sub-mode that turns off the fan automatically when the air quality sensors detect clean air for 10 minutes. The essence of this is to give you a much more energy-efficient air purifier.

coway airmega 400 top panel 1


Coverage and ACH and CADR ratings

As stated earlier on, this air purifier offers a coverage of up to 1,560 sq. ft. You might want to consider it if you are looking for an air purifier for large spaces, such as spacious living rooms, combination living, dining, and kitchen open-floor space, garage, gym, and basements.

The Coway Airmega has an ACH rating of 2x. ACH stands for Air Changes per Hour and refers to the number of times that an air purifier will change the air in a room within 1 hour.

This implies that this unit will refresh the air in a 1,560 sq.ft. space twice per hour. This ACH rating will increase if you use the purifier in smaller rooms. 

Coway does not offer the CADR for this model. CADR (Clean Air Delivery Rate) is a measure of how fast an air purifier can deliver contaminant-free air.

Importantly, the absence of CADR doesn’t make this model an underperformer. If anything, this rating isn’t a measure of an air purifier’s effectiveness in particulate removal. Thus, some manufacturers choose to ignore the test.

Noise level review

This is yet another area where the Airmega 400 impresses us. Despite its broad coverage- which calls for a powerful motor system- this model still maintains its noise level to 22-52 dB.

At its lowest setting, this purifier is whisper-silent and, therefore, perfect for use in bedrooms and recording studios. While its highest setting is a little bit louder, it’s still quieter than your AC. 

Power Usage

This is an Energy Star-certified air purifier rated at 64 watts. This wattage means that running the Coway 400 for 12 hours daily at the highest speed level would cost you roughly $34 annually (assuming that you pay $0.12 per kilowatt-hour of electricity).


As with most air purifiers, this model does not require complicated maintenance. You’ll only need to clean the pre-filters when the Pre-wash light indicates 0% and change the filtration kits annually.

The Max 2 Air Purifier Replacement Filter Set is priced at the higher end of the scale. You’ll get 2 filter kits, each containing True-HEPA and Activated Charcoal filters. The fact that these filters come in a single pack makes the replacement process a breeze.


This air purifier comes with a limited manufacturer’s warranty that covers any malfunctions for 1 year. The motor and electronic components are covered for 5 years.


  • Wide purifying coverage
  • 3-stage filtration process 
  • Accurate air quality sensors
  • Has Eco-mode 
  • Long warranty


  • Relatively pricier filters
  • No remote or App control
  • Lacks a settings lock function
  • A bit heavy

Our Verdict

The Coway Airmega 400 impressed us on all fronts that make a great air purifier for large spaces. It has a powerful motor system for broader coverage, an impressive design, and it’s effortless to set up, use, and maintain.

Its replacement filters aren’t the most affordable, but they last long. In our opinion, if you want a good-looking air purifier for big spaces, this model has a lot to offer.

Coway Airmega 400 Questions & Answers

How loud is the Airmega 400?

Its noise level ranges from 22 dB (whisper-quiet) to 52 dB (quieter than a normal conversation).

Can the 1,560 sq.ft. coverage be split into several rooms?

No. This coverage is meant for large spaces with an open floor. You could use the handles to take it to another room, though.

Can you turn off the LED lights completely?

Sure. Tap and hold the button with a bulb pictogram for a few seconds.

5 Expert Use Tips

  • If white noise improves the quality of your sleep, consider setting the fan speed at level 2 at night. 
  • Clean the pre-filter frequently to prolong the lifespan of the Max2 filter kit. 
  • If your room arrangement allows, place this model at the center for optimum performance. 
  • Ensure some clearance all around the unit for unobstructed air suction and airflow. 
  • Consider putting this purifier closer to the source of pollutants. For instance, if you want to control pet odor, set it closer to the litter box or cage.