Photo of AIRMEGA 400

Are you interested in the Coway AIRMEGA 400 air purifier?

But not sure if it’s the right one for you?

If so, you’ve landed on the right page.

In this post, you’ll find a comprehensive Coway AIRMEGA 400 review that’ll help you decide if you should buy this air purifier or not.

Overall, the 400 series does offer tremendous value for the price and it has some of the largest air cleaning coverage around, but will it clean the air to your standards?

Let’s find out in this review.

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Coway AIRMEGA 400 Review

Before we get into the air cleaning specifics, the first thing you need to know is that the Coway AIRMEGA 400 air purifier actually comes in two versions:

So, technically this will be a combined AIRMEGA 400 and AIRMEGA 400S review.

The only difference between the two models is that the 400S version offers Wi-Fi smart control.

Every other feature on these air purifiers is identical.

With the AIRMEGA 400 version, you do get the luxury of a remote control.

With the AIRMEGA 400S, you get some additional benefits from Coway’s mobile application:

  • Full control through a smartphone or tablet
  • Indoor and outdoor air quality monitoring
  • Filter change notifications
  • Scheduling
  • Alexa voice control

If you want the most modern air purifier that can be linked to your iOS or Android device, then the AIRMEGA 400S is the better purchase.

If Wi-Fi controls don’t matter to you, then the AIRMEGA 400 version can save you about $100.

AIRMEGA 400 Air Filter Types

No matter which version you choose, the AIRMEGA 400 or 400S, you’ll get the advantage of these two filters:

  • Pre-filter — Traps the largest pollutants, like dust, hair, and dirt, in a fine micromesh material. This filter also works to extends the life of the main filter, called the Max2 filter.
  • Max2 Filter — This is a highly specialized filter that combines two air cleaning technologies in one:
    • True HEPA Filter: Captures 99.97% of ultrafine particles down to 0.3 microns in size. This eliminates contaminants such as allergens, mold spores, bacteria, and particulate matter (PM2.5).
    • Activated Carbon Filter: Reduces 99% of Volatile Organic Compounds (VOCs) and fumes such as NH3 and CH3CHO which are toxic to your health.

The pre-filter is permanent and never needs to be replaced. Just wash it regularly with soap and water to clean off the trapped particles.

The Max2 Filter, on the other hand, is not permanent. It must be replaced when it gets full of pollutants, which is about every 12 months.

The average cost for replacing the Max2 Filter is $120. While that may seem a bit pricey, it’s actually a reasonable cost for an air purifier of this magnitude.

AIRMEGA 400 Top Features

AIRMEGA 400 Review Photo 2

While the AIRMEGA 400 series is packed full of great features, there are a few things that make it stand out from the competition. Those include:

  • Instant Air Quality Indicator — Know exactly how clean or polluted your indoor air is just by looking at the unit. Displayed as a colored ring.
    • Blue= Good
    • Purple = Moderate
    • Pink = Unhealthy
    • Red = Very Unhealthy
  • Dual Sided Suction — Air is pulled into the unit from two sides to clean it faster and more efficiently. Other air purifiers only draw air in from one side.
  • Eco Mode — Saves on energy and extends the life of the internal filters. The unit automatically turns off when it senses that the air quality is good for 10 minutes or more. Once air quality drops, the unit will automatically turn back on again.
  • Convenient Controls — Both the 400 and 400S include a remote control in addition to easy touch button controls on the unit. The 400S also gives you the added benefit of a mobile application.
  • Quiet — Only the highest speed is considered noisy. Noise levels range between 22~52 dB.

See More Features on

AIRMEGA 400 Room Size Coverage

The AIRMEGA 400 and 400S air purifiers are some of the most powerful machines you can buy today.

These products can handle up to 1,560 square feet (sq. ft.) which is more than enough for most indoor applications.

The AIRMEGA 400 series can purify very large areas like:

  • Large living areas
  • Combination living/dining/kitchen rooms (i.e. open floor plan)
  • Basements
  • Garages and workshops
  • Commercial office spaces

If you want something a bit smaller, Coway also makes a 300 series that covers up to 1,256 sq. ft. You can view our Coway AIRMEGA 300 Review here.

That model is featured on our best air purifier for large rooms list.

ACH Rating

The ACH stands for Air Changes Per Hour and this rating tells you how many times per hour the unit can exchange the full volume of air inside a specific size area.

For 1,560 sq. ft., the AIRMEGA 400 and 400S deliver a 2X ACH rating. This means that all of the room air is recycled two times each hour.

While that may sound like a good thing, the best air purifiers actually have a 4X ACH rating or higher.

However, you can still achieve a 4X ACH rating with the AIRMEGA 400 series if you use the unit in a room that’s half the size that’s recommended.

For example, the AIRMEGA 400 can be boosted to a 4X ACH rating when operating in a room that’s 780 sq. ft. or smaller (1,560 sq.ft. ÷ 2 = 780 sq. ft.)

We explain how this idea work in our article on how to calculate ACH.

CADR Rating

Some air purifiers include a CADR rating which indicates an exact score for filtering out tobacco smoke, pollen, and dust particles for a given room size.

CADR stands for Clean Air Delivery Rate and it’s issued by the Association of Home Appliance Manufacturers (AHAM), an independent testing organization for air cleaning devices.

This air purifier doesn’t have a CADR verification, so we can’t give you those numbers in our Coway AIRMEGA 400 review.

The absence of a CADR rating doesn’t make this a lower quality air purifier. Some manufacturers just choose not to pay for this third-party test.

AIRMEGA 400 Design and Size

You’ll likely agree that this is one of the nicest looking air purifiers you can buy today.

The modern design offers an excellent blend of form and function.

What’s great about this product is that it’s made to look more like a piece of furniture and not a bulky air purifier. The shape and design give it the appearance of an audio speaker or a side table.

It’s also not too big or heavy to move around. The exact dimensions and weight include:

  • 22.8″ (H) x 14.8″ (W) x 14.8″ (D)
  • 24.7 pounds

As for color options, you get two choices: white or graphite.

See the Colors on

Who is the AIRMEGA 400 Air Purifier for?

This air purifier series is an excellent choice for anyone who wants to improve the air quality in a large house or office space.

But to be specific, here are the persons who will notice the most dramatic effects by using the AIRMEGA 400 or 400S:

  • Allergy sufferers
  • People with multiple chemical sensitivities
  • People exposed to high levels of outdoor PM2.5 air pollution (i.e. automobile exhaust from city living)
  • People who like to cook and want to reduce odors
  • Anyone looking for the best air purifier for office air quality improvement
  • Light smoking
  • Anyone with large indoor areas to cover

AIRMEGA 400 Warranty Information

Coway offers an exceptional warranty on these air purifiers. You get a long 5-year limited warranty on the motor and electric parts.

That’s very generous considering that many other air purifier brands only give you a one or two-year warranty on their products.

What Others Have to Say About the AIRMEGA 400 Series

Are you wondering what other people think of these air purifiers?

If so, check out more Coway AIRMEGA 400 reviews and AIRMEGA 400S reviews on Amazon using the link below.

See Reviews

We hope that those comments and this review help you decide on if this is the right air purifier for you or not.