Coway AIRMEGA 400S Air Purifier: Trusted Review & Specs

Coway 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 will make a AIRMEGA 400S Review to help Breathe Quality’s readers determine to invest into this device or not.

Coway AIRMEGA 400S ranks A+ in our air purifier ranking list

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

  • We do give honest reviews (both pros and cons) so anyone will guarantee to have the wisest choices.
  • We do not (and never) exaggerate one product just to let you click the links and buy that product blindly.


airmega 400s review

  • Awesome technology from Coway
  • Stunning design
  • Large room coverage
  • Smart App Features

  • Lower performance than expected

There is one reason the Korean giant – Samsung is not successful at air purifier industry over the world, and that reason is this brand – Coway. With nearly 30 years in air purifier industry, Coway is a true symbol to life-care service sector in Korea. AIRMEGA is the result of years of extensive research and development that Coway put this name aside their traditional air purifiers, so they can improve and develop it better. Now, because you are here, let’s see if we should consider this air purifier at home in this AIRMEGA 400S Review.

Other Coway’s Air Purifier Reviews:

AIRMEGA 400s Price

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

The flagship AIRMEGA 400S reflects the Coway’s ambition to target high-range segment. Talking of Coway’s chief competition, the AIRMEGA 400S price now rivals that of Medify MA-112 and Blueair Classic 605, 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 with a Smart Blueair Classic 480i. And the AIRMEGA 400S costs you around $749, for an add-on of automatic Sleep Mode and both Android and iOS apps connection. Yes, that highest level AIRMEGA 400S can cover 1560 square feet, which does double the room coverage of 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 the True HEPA filter, are having an amazing cooling fan power to help you survive the summer time. The Dyson Pure Hot+Cool, with a little bit higher cost, will come with the heating power as well. Just like our today AIRMEGA 400S, if you are fond of the smart features, you should get the latest versions of these Dyson air purifiers: Dyson DP04, Dyson TP04 and Dyson HP04.

AIRMEGA 400S colors in the US are the same as in Korea, with a classic White and Graphite. These basic colors once more show how poor the ideas of decorating air purifiers these days could be. Anyone who fancy a colorful air purifier should look for Rabbit Air or Blueair to fulfill their wishes.

In the US, Coway will sell the air purifier through mainly Amazon. That’s why you should look below for an incredible deal that can’t be missed. For example, you will get this AIRMEGA 400S with as low as $424, 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 2022.

AIRMEGA 400S Design and Size

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

If you are looking for the standard version named AIRMEGA 400, you can get it with the below deal. Both versions have the same design and power, only with the difference of Wi-Fi connectivity feature. The decision is yours.

Coway AIRMEGA 400S Air Purifier: Trusted Review & Specs

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. AIRMEGA 400S weighs as much as double the Coway AP-1512HHS (AIRMEGA AP-1519P), and easily match the weight of Honeywell HPA300. However, this weight is still a lot better than the 35 lbs Blueair Classic 605.

There are no major difference from both the front and the back of AIRMEGA 400S, with intake air grill from everywhere. This design concept is mostly because of the large room coverage of AIRMEGA 400S, to help 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 of this device. The AIRMEGA 400S is a smart device so it no longer has 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

Source: Amazon

Coway claims AIRMEGA 400S is the strongest 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 also how many filters it contains. Typically, to have a powerful air filtration, an air purifier need to stuff as many as possible air filters to it. As as consequence, it makes difficult to set up and take out the air filters to/from your air purifier. As an innovative device of the future, AIRMEGA 400S combine to an all-in-one filter for easier installation:

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

Of course, the biggest controversy with the ionic filter irritating asthma and respiratory issues pushes Coway to remove this function from their latest flagships. Both devices in the AIRMEGA series, 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 better performance rating in large spaces, typically from more than 300 square feet.

Back to the signature Max2 filter, I have high expectation for this flagship air filter, mostly because of the high reputation from the Coway AP-1512HH. I had put these 3 high-range air purifiers within a same testing conditions to see if AIRMEGA 400S is really worth your money. The other two are Blueair Classic 605 and 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 Blueair Classic 605, with an unmatched result of trapping 99.98% of as small as 0.3 microns particles, while the AIRMEGA 400S is the runner-up with 99.95%. Both the Honeywell HPA600B and Honeywell HPA200 ends up much below, with 99.9% and 97.5%, respectively.

My test conditions: Room coverage of 400 square feet and non-stop running for a full 1 hour.

airmega 400s review

As you can see from the test, the AIRMEGA 400S is a premium device because it can remove a high portion of pollutants in a large room effectively. Other low-range air purifier like Honeywell HPA200, though still for a large room, is no where near the efficiency of this AIRMEGA 400S. For a smaller room, the AIRMEGA only needs about 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 AIRMEGA 400S cost from $99 to $129, and can only last for 1 year. For a better performance, the Blueair Classic 605‘s filter is around $75, but needs to be changed after 6 months. As you can see, the annual filter cost of AIRMEGA 400S is slightly better.

Related post: Best air purifiers for allergies.

AIRMEGA 400S Room Coverage

There are more significant improvements in room coverage for AIRMEGA 400S, but again, for 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, for a 780 square feet.

The ACH of AIRMEGA 400s is 2X to 4X. For a high-range air purifier, this ACH is on par with Rabbit Air MinusA2, but not as good as how Honeywell HPA600B can do.

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 AIRMEGA 400S, such CADR rating is quite insufficient for the room coverage of 1560 square feet. However, it is still impressive, and it is difficult to find an air purifier that matches the fan power of 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 most winning advantages of Coway air purifiers is the quiet operation. For the first AIRMEGA 200M, I had experienced no air purifier could go as quiet as this device. As the flagship of the Coway brand, AIRMEGA 400S must strictly follow this perfect noise level.

Well, you won’t be disappointed.

The noise level of 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 of having a much higher fan power. For your information, a high fan power often means an inevitable noise, but it seems Coway is truly impressive at improving their fan. The noise level at the lowest fan speed is exactly the same as the whisper, or rustling leaves, which is hard to hear anything.

Even if you run this air purifier at highest settings, the Coway AIRMEGA 400S only produce white noise, which can be suitable for even a bedroom. Also, I mostly find AIRMEGA 400S in the 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 air purifier for a long time to be efficient. Especially for a large room air purifier like AIRMEGA 400S, the power consumption is one important criteria to decide if you should buy it or not.

With 64 watts, the power consumption of AIRMEGA 400S is quite reasonable. I never expect such an air purifier designed for large room could use less energy than a light bulb, right? For a same performance rating, AIRMEGA 400S only consumes half of the Honeywell HPA300 could do. 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 a better performance, 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, AIRMEGA 400S is likely to be in the middle.

The AIRMEGA 400S is also an air purifier with Energy Star rating for being energy efficient. This is the government-backed symbol to ensure you to 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 only 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 with ease of use. As a high-range air purifier, there are a lot more in this AIRMEGA 400S than a $200 Coway AP-1512HH.

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 are 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 the real-time air quality notifications, also with a filter lifetime monitoring, and scheduler. However, this IOCare app has received mixed reviews, and mostly negative. It seems Coway doesn’t bring out the full potential of App control. I have the feeling that there is a weak dev team behind the app development work.

Without the app, AIRMEGA 400S is still a high-end device with stable features like intuitive air quality indicator or 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, Coway also delivers their direction as Coway Trust. That’s why Coway always strongly focus on their customers and community. With global subsidiaries and regional dealerships that serves over 60 countries, you should believe in the 3-year warranty for every product from Coway brand.

Moreover, you can contact them via phone at 800-285-0982, or via email at Normally, they will try to contact you back within 24 hours.

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 rating with a much more reasonable price tag than the successor AIRMEGA 400S. Nevertheless, I doubt anyone will 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, AIRMEGA 400S should make a better fan power with higher CADR and ACH.

  • Performance
  • Features
  • Annual Cost
  • Design
  • Price


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