Coway Airmega 400S Air Purifier: Trusted Review & Specs

Coway’s latest flagship – the Airmega 400S (AP-2015E) is a vital device that will almost certainly shape the design of the iconic series going forward. Today, we deliver the trusted Airmega 400S Review to help Breathe Quality’s readers determine whether to invest in this device or not.

The Coway Airmega 400S has been the best air purifier for 5 years, so we highly recommend you get it, especially when it’s on sale.

Update: The Airmega Icon is the newest system from Coway and costs nearly the same as the Airmega 400S.

Coway Airmega 400S ranks A+ in our air purifier ranking list. We give the biggest and most thorough database of air purifier reviews in the world.

In Breathe Quality, we have reviewed all air purifiers under these sections. Also, we guarantee that:

  • We provide honest reviews (both pros and cons) so that everyone can make the best decisions.
  • We do not (and never will) exaggerate one product just to let you click the links and buy that product blindly.


airmega 400s review

  • Great performance
  • Stunning design
  • Large room coverage
  • Smart features

  • 3-year warranty is a bit lower

There is one obstacle keeping Samsung from being successful in the air purifier industry around the world, and this obstacle is Coway. With more than 30 years in the air purifier industry, Coway is a true symbol of the life-care service sector in South Korea. The Airmega lineup is the result of years of extensive research and development. Coway gives this name to the modern air purifiers so the company can improve and develop them better. Now, let’s see whether we should consider this air purifier at home or not in this Airmega 400S Review.

Other Coway’s Air Purifier Reviews:

AIRMEGA 400s Price

As good as the Airmega 400S is, it’s not perfect. It also comes at a cost that might make you think it through.

The flagship Airmega 400S reflects Coway’s ambition to target the high-range segment. Speaking of Coway’s chief competition, the Airmega 400S’ price rivals that of the Medify MA-125 and Rabbit Air A3, rather than undercutting it as we’d hoped from an Asian brand.

The Airmega 400 (the no-app model) price at launch was $649, which is exactly the same as a smart Rabbit Air MinusA2. And the Airmega 400S costs you around $749, adding automatic Sleep Mode and smartphone app connection. Yes, the largest room coverage of the Airmega 400S is 1560 square feet, which does double the room coverage of the Blueair Classic 605. But is it better? We will find out soon.

We also notice the presence of the Dyson Pure Cool Tower and Dyson Pure Cool Link in the same price range. These air purifiers, besides having a true HEPA filter, have a cooling fan to help you survive the summer. These air purifiers, besides having a true HEPA filter, have a cooling fan to help you survive the summer. The Dyson Pure Hot+Cool, with a little bit higher cost, comes with the heating power as well. Just like the Airmega 400S, if you are fond of the smart features, you should get the latest versions of these Dyson air purifiers: the Dyson DP04Dyson TP04 and Dyson HP04.

The colors of the Airmega 400S in the U.S. are the same as in Korea, with classic White and Graphite. These basic colors demonstrate how bad today’s decorating ideas for air purifiers can be. Anyone who fancies a colorful air purifier should look for Rabbit Air or Blueair to fulfill their wishes.

In the US, Coway sells air purifiers mainly on Amazon. That’s why you should look for an incredible deal that can’t be missed. For example, you will get this Airmega 400S for as low as $429, which is truly impressive.

Top Airmega 400S deals right now

Coway Airmega 400S Air Purifier with best air filtration technology in Graphite Edition.

The stylish Graphite edition for one of the best air purifiers right now. Deal for a limited time. Pay as low as $34/month. Free Shipping.

Related post: Best air purifier 2023.

AIRMEGA 400S Design and Size

Coway has never coasted for too long with any type of design. And that all changed since the Airmega 300S, in a big way. The Airmega 400S closely resembles this design style, but with a bigger form. However, the Airmega 400S genuinely offers something different. The size is bigger at 22.8 inches in height and 14.8 inches in both depth and width, compared with the 21.2 inches in height of the Airmega 300S.

If you are looking for the standard version, named Airmega 400, you can get it below. Both versions share the same design and power, with the exception of Wi-Fi connectivity. The decision is yours.

Coway Airmega 400S Air Purifier: Trusted Review & Specs

The Airmega 400S packs all the design tweaks and material choices that debuted with the Airmega 300S: a bulky device with 4 legs. This air purifier feels thicker and more difficult to move from one place to another. Grabbing it one-handed has proved a hard feat for me, with a very narrow handle and a weight of 24.7 lbs. The Airmega 400S weighs as much as double the Coway AP-1512HHS (Airmega AP-1519P) and easily matches the weight of the Honeywell HPA300. However, this weight is still a lot better than the 35-lb Blueair Classic 605.

There are no major differences between the front and back of the Airmega 400S, which has a 360° intake air grill. This design concept is mostly to maximize the room coverage of the Airmega 400S, helping you put this air purifier anywhere to reach maximum efficiency. The only exception is the air quality indicator on the front to show the current air quality in your room.

On top of this air purifier is a typical outlet air vent to take out the fresh air. There you will find the controller for this device. The Airmega 400S is a smart device, so it doesn’t have as many buttons as the previous Coway air purifiers. We will only have one on/off button and two air filter indicators.

airmega 400s review


Coway claims that the Airmega 400S is its strongest air purifier ever. From both its look and the pretty well-built materials, we could expect a device that could last for a long time.

Related post: Best air purifiers for bedroom.

AIRMEGA 400S Filters

The unique feature on the Airmega 400S is the filters. To test the performance of an air purifier, you need to know the power of its air filters and how many filters it contains. Typically, to have powerful air filtration, an air purifier needs to stuff as many air filters into it as possible. As a consequence, it is difficult to set up and take out the air filters from your air purifier. As an innovative device of the future, the Airmega 400S combines an all-in-one filter for easier installation:

  1. Pre-filter – A powerful washable pre-filter is available to capture large objects of contaminants. Remember to dry the pre-filter before re-installing it.
  2. Max2 filter – Combining both an Activated Carbon filter and a True HEPA filter, this filter can capture up to 99.97% of airborne particles smaller than 0.3 microns. It also reduces more than 99 percent of volatile organic compounds and fumes, such as NH3 and CH3CHO.

Of course, the biggest controversy over the ionic filter irritating asthma and respiratory issues pushed Coway to remove this function from its latest flagships. Both devices in the Airmega series, the 300S and 400S, will have no ionizer feature at all. However, that’s not a great issue for the high-quality True HEPA filter of your Airmega 400S. For the Max2 filter, it doubles the size of a normal Coway anti-virus HEPA filter. A bigger size air filter usually means a better performance rating in large spaces, typically more than 300 square feet.

Back to the signature Max2 filter: I have high expectations for this flagship air filter, mostly because of its high reputation starting with the Coway AP-1512HH. I had put these 3 high-range air purifiers under the same testing conditions to see if the Airmega 400S was really worth your money. The other two are the Blueair Classic 605 and the Honeywell HPA600B. Also, to show you why you need a high-range air purifier, I also run a low-range Honeywell HPA200 at the same conditions. The clear winner was the Blueair Classic 605, with an unmatched result of trapping 99.98% of particles as small as 0.3 microns, while the Airmega 400S is the runner-up with 99.95%. Both the Honeywell HPA600B and Honeywell HPA200 end up much lower, with 99.9% and 97.5%, respectively.

airmega 400s review

As you can see from the test, the Airmega 400S is a premium device because it can effectively remove a high portion of pollutants from a large room. Other low-range air purifiers like the Honeywell HPA200, though still suitable for a large room, are nowhere near the efficiency of the Airmega 400S. For a smaller room, the Airmega 400S only needs 30 minutes to deal with all the contaminants.

You are in the high-range market; therefore, you can’t expect a cheap air filter cost. The Max2 filter of the Airmega 400S costs from $99 to $129 and can only last 1 year. For better performance, the Blueair Classic 605‘s filter is around $75, but it needs to be changed after 6 months. As you can see, the annual filter cost of the Airmega 400S is still slightly better.

Related post: Best air purifiers for allergies.

AIRMEGA 400S Room Coverage

There are more significant improvements in room coverage for the Airmega 400S, but again, at the sacrifice of other specs. In the manual, the Airmega 400S states that it can cover up to 1560 square feet. But if you double the air changes per hour (ACH), this air purifier is only effective at exactly half its capacity, or 780 square feet.

The ACH of Airmega 400s is 2X to 4X. For a high-range air purifier, the Airmega 400S can clean your room every 15 minutes.

The CADR of Airmega 400S is not told in the manual. But through many tests, I recorded a reliable CADR of 340 Dust/ 350 Smoke/ 400 Pollen (cfm). For a large room air purifier like the Airmega 400S, such a CADR rating is quite insufficient for the room coverage of 1560 square feet. However, it is not really bad, and it is difficult to find an air purifier that matches the fan power of the Airmega 400S in the same price range.

Related post: Best large room air purifiers.

AIRMEGA 400S Sound

We can all agree that one of the best advantages of Coway air purifiers is their quiet operation. For the first Airmega 200M, I experienced that no air purifier could go as quiet as this device. As the flagship of the Coway brand, the Airmega 400S must strictly follow this perfect noise level.

Well, you won’t be disappointed.

The noise level of the Coway Airmega 400S ranges from 22 decibels to a maximum of 52 decibels (dB). This air purifier is as quiet as the Ultra-quiet Rabbit Air MinusA2, despite having much higher fan power. For your information, high fan power often means an inevitable noise, but it seems Coway is truly impressive at improving its fan motor. The noise level at the lowest fan speed is exactly the same as a whisper or rustling leaves, which is nearly silent.

Even if you run this air purifier on the highest speed, the Coway Airmega 400S only produces white noise, which can be suitable for a bedroom. Also, I regularly find the Airmega 400S in professional offices.

Related post: Best air purifiers for baby.

AIRMEGA 400S Power Consumption

One of our most FAQs is “Do air purifiers use a lot of energy?” The fact is, you need to use an air purifier for a long time to be efficient. Especially for a large room air purifier like the Airmega 400S, the power consumption is an important criterion to consider before deciding if you should buy it or not.

With 64 watts, the power consumption of the Airmega 400S is quite reasonable. I never expected an air purifier designed for large rooms could use less energy than a light bulb. The Airmega 400S consumes half the power of the Honeywell HPA300 for better performance. Also, thanks to the reliable Eco Mode, I would expect much less energy to be consumed by this air purifier.

For a quick comparison, the Blueair Classic 605 has better power, but the highest power consumption can be 100 watts. Or the Honeywell HPA600B with less room coverage but better power consumption of 44 watts. Again, the Airmega 400S is likely to be in the middle.

The Airmega 400S is also an air purifier with an Energy Star rating for being energy efficient. This is the government-backed symbol to ensure you get the most efficient air purifier.

Efficiently, it would cost you around $24 per year. That means the Airmega 400S has a double cleaning power with the same energy cost as the Winix WAC9500 or Winix 5500-2.

Related post: Best air purifiers for pets.

AIRMEGA 400S Additional Features

Additional features are handy for making a high-end air purifier easy to use. As a high-range air purifier, there’s a lot more in this Airmega 400S than in a $200 Coway AP-1512HH. However, it seems Coway has delivered the same smart features in its next-gen mid-range products, most notably the Airmega 250.

First, you will benefit from the most accurate Smart Sensor in the world. There’s so much to say about the Coway automatic features, and most of them get good reviews. Most importantly, the unique Eco Mode from Coway air purifiers will help reduce the power consumption to as low as possible.

airmega 400s review

But the most anticipated part of this flagship is the “smart app enabled” function. Using the Coway IOCare Mobile app, you will receive real-time air quality notifications, along with filter lifetime monitoring and a scheduler. However, the IOCare app has received mixed reviews, which are mostly negative. It seems Coway doesn’t bring out the full potential of the smartphone app. Not anymore; the app works great now.

Without the app, the Airmega 400S is still a high-end device with stable features like an intuitive air quality indicator or an LED filter replacement indicator.

Related posts:

1, Best air purifiers for smoke.

2, Best air purifiers for dust.

3, Best air purifiers for mold.

AIRMEGA 400S Customer Service

As one of the top electronic brands in Korea, Coway is somehow as huge as Samsung. This brand not only carries out clean innovations for the customers, but Coway also delivers its direction as Coway Trust. That’s why Coway always places a strong focus on its customers and community. With global subsidiaries and regional dealerships that serve over 60 countries, you should believe in the customer service of the company.

Moreover, you can contact Coway’s customer service via phone at 800-285-0982 or via email at Normally, customer service will try to contact you within 24 hours.

All air purifiers made by Coway have their motor and electronic parts warranted for 3 years, while other internals are warranted for 1 year.

Top Airmega 400S deals right now

Coway Airmega 400S Air Purifier with best air filtration technology in Graphite Edition.

The stylish Graphite edition for one of the best air purifiers right now. Deal for a limited time. Pay as low as $34/month. Free Shipping.

Our verdict

In the writer’s opinion, the Coway Airmega 300S offers the same performance ranking with a much more reasonable price tag than the successor Airmega 400S. Nevertheless, I doubt anyone can be unhappy with the great performance and features brought by the Airmega 400S. The one slight disappointment with regards to the power is that, within a large room coverage of 1560 square feet, the Airmega 400S will clean a lot less.

Coway Airmega 400S Air Purifier: Trusted Review in 2024
Coway Airmega 400S Air Purifier: Trusted Review & Specs

Coway Airmega 400S Reviews and Specs (Air Purifier Trusted Reviews in 2024). ✓ Cleaning Power: True HEPA ✓ Wifi: Great ✓ Value: 4.8/5 ✓ Certified Review.

Product Brand: Coway

Product Currency: USD

Product Price: 429

Product In-Stock:

Editor's Rating:
  • Performance
  • Features
  • Annual Cost
  • Design
  • Price


A worthy comeback of the Coway Airmega brand. Coway Airmega 400S has an excellent air filtration process and many additional features, but with an increase in the cost.