AIRMEGA 400s Review – Gimmicky Gadget or Awesome Air Purifier?

Air purifiers can cost several hundred dollars upwards so before investing your hard earned cash it’s really important to do some research to make sure the one you go for is the right fit for you.

If the Airmega 400s is something you’ve been considering then we’ve got the answers to all the crucial things you might want to know about it – like how big a space it can clean, key features and how easy it is to use, and what the purchase and running costs are for this unit. 

If you’re a little short on time you can hop straight to the section you’re most interested in by clicking the relevant link in the table below.

Or read on for our full product review and our independent verdict and star rating.

Let’s start by taking a look at who manufactures the Airmega 400s air purifier, and whether it’s a reputable brand you can have confidence in.

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Who Makes The AIRMEGA 400s Air Purifier?

The Airmega 400s was developed by a company called Coway and is said to be the most advanced air purifier currently in its portfolio.

Based at world-class facilities in Seoul, South Korea, Coway has an enviable reputation for creating innovative products which have the improvement of health at their core.

The geographical location of the company means it’s especially tuned in to issues around poor air quality and environmental safety.  It also claims to have a deep understanding of the importance of respiratory health and the difficulties caused by respiratory illness.

So, at first sight it certainly does appear to have very good credentials and is made by a well-known and respected brand.

Let’s now consider what size of room you can use the Airmega 400s air purifier in.

What Room Coverage Does The AIRMEGA 400s Offer?

We’re going to take a look at room coverage early on in this article for one very important reason – namely, if the unit can’t handle the space you intend to use it in then there’s little point in pursuing it further.

For normal residential use, 2 air changes per hour are considered sufficient.  For asthma and allergy sufferers 4 air changes per hour are recommended. 

The Airmega 400s can refresh the air twice an hour in a room up to 1560 square feet, and four times an hour in a space up to 780 square feet.

As you can see, the room coverage offered is very generous and probably far more than most people will require for an average-sized living room, bedroom or study.

Many other models I’ve reviewed only offer roughly half that capacity, so it’s definitely one of the largest available for a domestic use air purifier and should satisfy the needs of most people in that respect.

Let’s now consider exactly HOW the Airmega 400s cleans the air inside a room.

How Does The AIRMEGA 400s Work?

The Airmega 400s air purifier sucks the air inside a room in through both sides of the unit.  Polluted particles inside that air are trapped in a series of filters (discussed below) before clean, refreshed air is blown back out of the top of the machine.

The Airmega 400s doesn’t have a negative ion generator and so doesn’t produce any ozone.

(a) Pre-Filter

A micromesh pre-filter is the first thing that polluted particles come into contact with.  It weeds out the larger ones such as dust, hair and fur.

The pre-filter is washable and it’s recommended that you clean it on a regular basis, at least once a month.  This will help to prolong the life of the other more expensive filters as well as making sure your unit stays working efficiently.

(b) Max2 Filter

The Max2 filter has 2 parts to it: an activated carbon filter and a Green True HEPA filter.

The job of the activated carbon filter is to absorb unpleasant smells such as pet and cooking odors. Airmega also say the 400s air purifier can remove more than 99% of Volatile Organic Compounds (VOCs) from the indoor air, in addition to fumes such as NH3 and CH3CHO.

Without going into overly scientific detail, VOCs are essentially an air contaminant and are given off by many different things found in most homes such as household cleaning products, perfumes, air fresheners, paint, floor coverings and furniture.  So anything which can remove them before we breathe them in is most definitely a bonus.

The job of the Green True HEPA filter is to capture the smaller particles which slip through the pre-filter, including pollen and other allergens.

HEPA filters are subject to stringent standards of testing and must be able to capture up to 99.97% of airborne particles down to 0.3 microns in size.

You can read more about different particle sizes in our other article if you’d like, but suffice to say there won’t really be anything nasty left lurking in the air after it’s passed through this filter.

So, in terms of its ability to remove airborne allergens and contaminants the Airmega 400s does a very thorough job.

This unit doesn’t give customers the option to customize their filters like some other models I’ve reviewed recently, but I certainly don’t see that as a negative.  It does everything you need it to do, and instead you can leave it to the professionals to design the best type of filter, rather than trying to figure it out yourself.

How Long Do the Filters On The AIRMEGA 400s Last?

If you own an air purifier it’s a fact of life that you’ll have to replace the filters on it at some point – unfortunately there’s no getting away from it.  There’s only so long that all that junk can accumulate on the filters before you need to dispose of it.

The Airmega 400s takes away the guesswork on when it’s time to change the filters – the machine is equipped with a Max2 Filter Indicator light which lets you know when you need to make a replacement.

The unit also has a Pre-Filter Indicator light which lets you know when the pre-filter needs to be cleaned.

Removing and replacing the Max2 filter is really easy. You simply pop open the side covers, take out the old filter,replace with a new one then close the unit back up again.

Unlike some other air purifiers which recommend a filter change after a certain length of time, the Airmega 400s gauges filter lifespan based on usage.  So obviously the more you use it, the earlier the filter will need replaced.

Airmega anticipate that most filters will last for approximately 12 months.

What’s The Cost Of Replacement Filters For The AIRMEGA 400s?

At the time of writing, replacement Max2 filters for the Airmega 400s are retailing in the region of $99-129.

At the highest price that works out at a cost of approximately 35 cents a day over the course of a year, which I think is pretty amazing value to be able to enjoy clean, pure air.

So, we now know that this air purifier can cover a large space and offers great air cleaning power thanks to its HEPA filter.  Let’s now take a look at what other features the Airmega 400s has to offer.

Intelligent Technology – 3 ‘Smart’ Modes to Make Life Easier

The first generation of air purifiers were a bit more basic in their operation than today’s models, and users typically had to operate all the different settings manually.

Today the technology is far more advanced and many air purifiers are doing most of the work themselves when it comes to determining the best fan speeds and ambience settings to use.

The Airmega 400s features 3 such ‘smart’ modes – auto, eco and sleep.  Let’s take a look at each.

(a) Smart Auto Mode

If you decide to engage the auto mode feature the unit uses a sensor to detect how much pollutants are in your indoor air and then adjusts the fan speed accordingly.

There are 4 fan speed settings on the Airmega 400s – sleep, low, medium and high.  As a rule of thumb, the more pollutants are detected, the faster the fan will operate.

When the sensor recognises that the indoor air quality has improved it will switch back down to a lower fan speed.

(b) Smart Eco Mode

If the unit is in smart mode and the sensor has detected good air quality for a period of 10 minutes, the machine will automatically shut down the fan.

This helps to save on your energy consumption, and in turn saves you money on your electricity bills, as it means you’re not running the air purifier when it’s not necessary.

The fans will automatically start back up again should the sensor detect any pollution later.

(c) Smart Sleep Mode

In sleep mode the unit will reduce its noise and power consumption if the sensor detects the room has been dark and the air clean for a period of 3 minutes.

Like the eco mode, this feature is good both for the environment and your bank balance!  It’s also handy if you plan to use the air purifier in your bedroom at night as it helps to minimise disturbance and let’s you get a better nights sleep.

Real-Time Air Quality Monitoring

Real-time air quality monitoring is another feature offered by the Airmega 400s air purifier.

A pollution sensor lets you know what your indoor air quality is like in real-time, and an LED ring on the front of the unit changes color depending on the detected pollution levels.


I guess if you’re using the smart auto mode then this feature isn’t crucial as your unit will be adapting its fan speed accordingly anyway when the air quality deteriorates.

That said, it’s still handy in that you can see the quality of your air minute-by-minute at a quick glance, and see if something in particular triggers an immediate decline – for example, if you spray some air freshener or perfume.

If you know for sure that something is negatively affecting the air you’re breathing you can then choose whether to continue using it or not, so this feature makes it much easier for you to identify air quality offenders.

Ok, let’s now consider another piece of technology which the Airmega 400s boasts – the compatible mobile app.

The AIRMEGA 400s Mobile App – Allows You To Control Your Purifier Remotely

There’s so much stuff we can do on our smartphones these days!

I use mine to catch up on the latest news, listen to music, make videos, pay bills, work…the list is endless.

In recognition of the fact that so many of us like to use our phones for day-to-day tasks, Coway have developed a smartphone app (IOS and Android) which lets owners of the Airmega 400s control many aspects of their air purifier remotely.

For example, you can set the fan speed and sleep timer, see the status of the filters, and access the different smart mode controls.

You can also receive indoor air quality reports straight to your phone.  This lets you track the health of the air inside a room over a period of a few days or weeks, and is useful for identifying trends and the times when the air quality is at its best and worst.

You can also receive real-time updates on outdoor air quality and pollution levels for your particular hometown.

Unlike some other air purifier apps which require Bluetooth to be enabled before operation, this app only requires a WiFi connection (WiFi router frequency band 2.4GHz required).

Before connecting your smartphone and the air purifier you’ll firstly need to download the Airmega app from the Apple App store or Google Play store.

How Well Does The Mobile App Work?

Full details on connectivity can be found in the Users Manual, but it’s maybe worth mentioning at this point that a few customers online have reported some issues when trying to pair up the device with their phone.

Initially, some people found they had to make several attempts before they were able to successfully connect, while another remarked that the app could benefit from further work and have more features.


However, it appears that these technical issues have since been ironed out a lot.  The app has been updated, and the general opinion among most customers seems to be that it’s working better now.

Pair The AIRMEGA 400s With Amazon Alexa – FREE Smart Home Consultations Available

The Airmega 400s air purifier can also be paired with Amazon Alexa – the new favourite lady in my husband’s life, who is far more willing to do things for him than I am! 😉

At the time of writing this article (Sept. 2017), are offering FREE ‘Smart Home Consultations’ with purchases of the Airmega 400s through them.*

Here you can have your smart home questions answered by an expert, receive a home WiFi assessment to identify any issues, and learn how to build an Alexa smart home using voice commands.

(*Offers may be withdrawn or changed after this article has been published)

Ok, let’s now consider the look, weight and dimensions of the Airmega 400s.

What Colors Does The AIRMEGA 400s Come In?

The Airmega 400s is box-shaped and on legs, with the control buttons and air grill located on the top of the unit.


It comes in a choice of white or graphite, so is pretty neutral in style meaning it should blend easily into most decor schemes.

It doesn’t come with any panel customisation options, so if you’re after a really snazzy model that’s a real statement piece you may prefer something like the Rabbit Air Minus A2.

My own personal opinion is that it’s perhaps not as stylish as some other models out there. However, looks are of course a very subjective thing.  What looks plain and functional to one person is sleek and dynamic to the next.  It all comes down to personal preference.

And far more important than looks is how well an air purifier can actually clean the air, so do always bear that in mind when choosing which model is right for you.

Dimensions and Weight of the AIRMEGA 400s Air Purifier

Size-wise, the Airmega 400s measures in at 22.8″ (H) x 14.8″ (W) x 14.8″ (D).

It weighs 24.7 lbs (11.2kg) so is a quite a bit heavier than some other models on the market, but that’s probably down to the fact that it can be used for much larger spaces than many of its competitors.

It doesn’t come with castors – something to bear in mind if you were planning to move it from room to room on a regular basis.

How Quiet Is The AIRMEGA 400s? 

The Airmega 400s air purifier produces sounds of between 22-52 decibles (dB) depending on which fan speed is being used.  The higher the fan speed, the more audible the sound.

To help give those figures some context, a whisper registers at around 30dB, a library environment 40dB, and a normal conversation 60dB.

So it shapes up pretty well – not excessively loud on the highest setting, and barely audible on the lowest.

Let’s  go now to another important consideration when choosing an air purifier – the price.

How Much Does The AIRMEGA 400s Air Purifier Cost?

The full price of the Airmega 400s air purifier is in the region of $849, although at the time of writing it can be found discounted by $100 for the white version.

Peace of mind comes in the form of a 5 year warranty – more generous than the 2/3 year warranties typically found with air purifiers (always read the small print for any limitations or exclusions).

Now the Airmega 400s is undoubtedly at the higher end of the price scale for air purifiers BUT…

…when comparing prices always do a proper like-for-like comparison.  Yes, you can find cheaper units out there for sure, but do they offer the same level of room coverage?

Cheaper models I’ve looked at only cover half the room size of the Airmega 400s so don’t make your choice based on price alone – compare several different factors like room coverage, type of filters used, technology, and noise levels.

What Do Customers Say About The AIRMEGA 400s Air Purifier?

Before we finish off with my pros and cons for the Airmega 400s air purifier, let’s take a look at some recent feedback from customers online:

“Best air purifier I have owned, after trying out a few different ones…really traps lots of stuff and helps to clean out the air when we cook”

“Excellent value, works great, simple to maintain…virtually silent on night setting”

“I have a strong allergy to pet dander and mold, and this has noticeably improved my breathing and sinus symptoms”

“Would especially recommend to anyone who has pets”

“Nice air purifier, but the WiFi is very buggy”

“The WiFi and app would not stay connected…great idea but not perfected”

Pros and Cons of the AIRMEGA 400s

The title of this article asked whether I thought this was just a gimmicky gadget, or an awesome air purifier.

Here’s what I really like about it…

Excellent room coverage – perfect choice for larger spaces

Great coverage also for asthma and allergy sufferers, who need extra air changes per hour

HEPA filter technology for maximum particle removal

Carbon filter removes 99% of harmful VOCs from the indoor air

Real-Time Pollution Sensor – LED colored ring makes it very easy to identify air quality offenders at a quick glance

…and the flip side…

Issues reported with WiFi connectivity – sometimes difficult to pair up

No castors, so there may be mobility issues for some people

Limited choice of colors and no customization options

My Conclusion and Star Rating

Overall, I think the Airmega 400s air purifier is a great choice if you have a particularly large room, or if you suffer from allergies or asthma and need something that can refresh the air the recommended number of times per hour. To me the price tag is justified by this fantastic coverage.

There will be some people who’re prepared to pay for more coverage than they actually need in order to get the extra techy features – the ‘smart mode’ settings, the mobile app, and being able to pair it up with Amazon Alexa.

If you fall into that category then just be aware that there have been a few technical issues on that score, although it does look like the company have been working hard to fix these issues.

 I give the Airmega 400s Air Purifier an impressive 4.5 out 5 stars!

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