Airmega 400

Coway Airmega 400 Review: Flair without the Wi-Fi hassle!

A brand that defines modern purifier to the next level, Coway Airmega 400 is exceptional for long-haul purifying as verified on its build quality. Simple yet straightforward to use, this air purifier machine is remarkable for people that utilize it on a daily basis without the need to constantly monitoring the machine. Here is what most users considering Airmega would think about, should I get this over 300 series or should I top up a little more for the Wi-Fi version? Find out the answer and read more about the air purifier airflow delivery rate, coverage, noise level, and power consumption below.
± 749 p
     Annual filter ^    
± 130 p
Online price*
Latest Amazon price

Airmega 400 Specification

ProductAirmega 400
14.8 x 22.8 x 14.8 in
(37.6 x 57.9 x 37.6 cm)
Weight24.7 lb (11.2 kg)
Coverage (up to)1560 sq. ft. (145 m2)
Dust free (CADR)350 cfm (595 m3/h)
Pollen free (CADR)350 cfm (595 m3/h)
Smoke free (CADR)350 cfm (595 m3/h)
Airflow speed
- Lifespan
- Replacement cost ($)
Pre-filter (2 pack)
+- 25
HEPA filter
- Lifespan
- Replacement cost ($)
Max2 (Green True HEPA filter)
1 year
Carbon filter
- Lifespan
- Replacement cost ($)
Max2 (Activated carbon filter)
1 year
Ionizer/ Technologies
UV-light/ PCO
Other filter
All-in-one filter
- Lifespan
- Replacement cost ($)
Max2 Filter
1 year
+- 129.99
Optional/ Addon
Noise level22 - 52 dB
Power consumption6 - 66 W
Timer/ Scheduler1, 4, 8 hours
SensorsPollution sensor, Light sensor
More color options
Auto mode
Air qualityAQ indicator
Filter change indicator
Wi-Fi/ BTBluetooth
Remote control
Child lock
Warranty5 years
Email/ Phone support

Product image

Airmega 400 key features

  • 4-stage filtration
  • 2 Washable permanent Pre-filter
  • MAX2 filter (True HEPA filter + Activated Carbon filter)
  • 3 speed setting (Low, Medium, High)
  • Dual side air inlet
  • Separate Pre-filter and HEPA filter indicator based on real-time usage
  • Autonomous Smart mode - Auto, ECO and Sleep mode
  • Front AQ display indicator (Good, Moderate, Unhealthy, Very Unhealthy)
  • Adjustable pollution sensor's sensitivity (sensitive -1 bar, normal -2 bar, less sensitive - 3 bar)
  • Built-in timer (1, 4, 8 hours)
  • 5 years warranty

Airmega 400 review

  • 4-stage filtration with very wide purifying coverage.
  • Dual pre-filter that traps large particles from both sides of the air inlet.
  • Max2 filter (Green True HEPA + Activated Carbon) is great against smoke and micron size pollutants
  • Auto mode with adjustable sensitivity to set the ideal speed based on room air quality.
  • Sleep mode that automatically adjusts the light and speed accordingly when there is no light source.
  • Pre-filter and MAX2 filter lifespan indicator that is based on real-time usage and environment.
  • Clear and accurate real-time air quality display indicator.
  • 5 years Airmega official warranty.
  • Cheaper than 400S model but still relatively expensive.
  • Expensive filter replacement cost despite only one annual filter change (Max2 filter).
  • No remote access (via app) as 400 have to do without Wi-Fi connectivity support.
  • Lacks optional Ionizer feature even though not everyone would utilize it.

The starters

Airmega 400 dimension
14.8 x 22.8 x 14.8 in
(37.6 x 57.9 x 37.6 cm)
Airmega 400 weight
24.7 lb (11.2 kg)

A mirror to 400S, you can barely tell Coway Airmega 400 apart from its series. From the “smart” exterior design that seamlessly blends in the air intake, the air purifier looks modern and futuristic even from a far point. 14.8 x 22.8 x 14.8 in dimension and 24.7 lb weight is not super bulky considering the 4 legs stand comes as standard. Despite the lack of IoCare app and remote support, the air purifier used the same build materials that are solidly fitted with no uneven gap for air bypass or ozone emission. Up front, you will find a bright, LED air quality indicator that will show real-time indoor air quality. When air quality is good, the ring will change to Blue color, Purple when air quality is moderate, Pink when air quality is unhealthy, and Red when air quality is very unhealthy. Air inlet is located on both sides of the air purifier along with the handy gripping handle.

Coway Airmega 400 Control

Big, round buttons with plenty of indicator light, the control panel is nicely spread across both sides of the top panel. On the left corner, you will find a Timer button, Light button, Pre Wash button, and Max2 change button plus a round light sensor. Timer button will cycle between 1, 4, 8 hours of pre-set setting. Light button will turn on or off the front air quality indicator light. Like 400S, both Pre Wash and Max2 Change button will show the pre-filter Lifetime cleaning cycle at 5 levels: 100%, 80%, 60%, 49%, 20%, and 0%. To reset the Pre Wash and Max2 Change button light, clean (Pre Wash) or change (Max2) filter, then press and hold the respective button for 2-3 seconds. Light sensor works by detecting the warmth of the surrounding light. When everything is dark for 3 minutes and the air purifier is in Smart mode, sleep mode will activate automatically. Moving to the right corner, there are only two functions. The big Power button and a swipeable Air speed/ mode. The power button will turn on the air purifier on press while pressing and holding the button again for 2-3 seconds will turn it off. The Air speed/ Sleep mode selection is slightly quirky, either tap the curve bar on desired speed/ mode accordingly, or swipe up or down for a similar result. Lastly, there is one hidden function that most people didn’t know it exists unless they read the manual. The pollution sensor’s sensitivity can be adjusted by holding on the Light button + Smart bar. Select one of the air speed from speed 1 = sensitive, speed 2 = normal, speed 3 = less sensitive.

Again, here is the recap of the air purifier spec sheet. Starting with the 4 stage filtration, 3 fan speed, Smart mode (Auto/ Sleep/ Eco), two separate pre-filter/ HEPA filter indicator that based on real-time usage, air quality monitor, built-in timer (1, 4, 8 hours), 30 days money back guarantee, and 5 years warranty.

Airmega 400 airflow, speed, and CADR

Airmega 400 coverage
Purifying coverage
1560 sq. ft. (145 m2)
Airmega 400 fanspeed
Despite lacking the Wi-Fi functionality, Coway Airmega 400 never skim on airflow performance and coverage. Expect the exact airflow delivery rate and applicable area that is designed for large room size. At a maximum of 1560 sq. ft. with 2 air charges or 780 sq. ft. with 4 air charges, the air purifier produces plentiful of airflow for swift particles capturing. Adding an adjustable pollution sensor in the bag, you can easily rely on Smart mode for the air purifier to perform autonomous purifying according to surrounding air quality, or Sleep mode that reduce noise, power, and speed if your intention is to use at night.
Airmega 400 dust CADR
350 cfm (595 m3/h)
Airmega 400 pollen CADR
Pollen CADR
350 cfm (595 m3/h)
Airmega 400 smoke CADR
Smoke CADR
350 cfm (595 m3/h)
CADR is equally powerful as the airflow therefore it can provide swift cleaning against Dust, pollen, and smoke. At an overall of 350 cfm, the air purifier outpaces most competitor models at purifying efficiency. Combining the versatile Max2 filtration, whatever type or size of airborne particles, the air purifier will have no problem capturing it.

What’s inside count

Airmega 400 Pre-filter
Pre-filter (2 pack)
Airmega 400 HEPA filter
Max2 (Green True HEPA filter)
1 year
Airmega 400 carbon filter
Max2 (Activated carbon filter)
1 year
^ Airmega 400 filters/ technologies/ lifespan
As mentioned earlier, Coway Airmega 400 utilize a 4-stage filtration setup that consist of dual Pre-filter, Green True HEPA filter and Activated Carbon filter. How the filtration works are pretty straightforward. When airborne particles are sucked through either side of the air inlet, the Pre-filter will filter out as many particles as possible to give the Green True HEPA more freedom space. The freed Green HEPA filter would then focus on removing micron size particles (0.3 microns/ 99.97 efficiency) i.e. allergens, germs without being burden by dust and hair. On the other end, Activated Carbon filter would concentrate solely on smoke/ gases pollutants from flowing back out. Filter size and quality are up there but do note that this would be the end of the line as there is no Ionizer or UV-light in the whole filtration process.

Covered against

Airmega 400 VS Dust



Airmega 400 VS Pollen



Airmega 400 VS Hair

Hair/ Pet hair


Airmega 400 VS Dust mite

Dust mites


Airmega 400 VS Mold/ Mildew

Mold/ Mildew


Airmega 400 VS Pet dander

Pet dander


Airmega 400 VS Virus/ Germ

Virus/ Germ


Airmega 400 VS Tobacco smoke

Tobacco smoke


Airmega 400 VS Chemical



Airmega 400 VS VOCs



Airmega 400 VS Smoke/ Gas

Smoke/ Gas


Airmega 400 VS Odor



The dual pre-filter along with 1560 square feet coverage and overall 350 cfm clean air delivery rate is proven to be very useful in reducing airborne dust. What's more impressive is the Green True HEPA filter is highly capable of trapping pet dander, dust mites, pollen, mold, mildew, and bacteria even without the help of UV-light or Ionizer. The activated carbon filter is equally terrific in household product chemical vapor, pet odor, cooking/ fire smoke, and the common VOCs, cigarette smoke toxic.

Keep it down

Airmega 400 noise level
Noise level
22 - 52 dB
Airmega 400 power consumption
Power consumption
6 - 66 W
Noise level starts at 22 dB at low speed, and end at 52 dB at max speed. No the quietest air purifier around but is perfectly usable even in a bedroom. Given the air cleaner is Energy Star rated, expect a reasonable power usage of 6 watts (lowest speed) to a maximum of 66 watts at highest speed. For better energy management, Smart mode aka Auto/ Sleep/ Eco mode will ensure the air purifier conserve energy by operating the right fan speed to combat surrounding air pollutants. Eco mode will stop the fan from spinning when there is fresh air in a room for at least 10 minutes.

At what cost

Airmega 400 MRSP/ RSP
+- 749
Airmega 400 annual filter replacement cost
Annual Filter Cost
+- 130
^ Replacement filters/ estimated cost
Coway Airmega 400 air purifier is the non-Wi-Fi version as oppose to the Wi-Fi ready 400S. As such, pricing will be cheaper but do not expect the margin to be huge given the specification is identical. What you can expect is the same pricing for both white or graphite color variant. Expensive the air purifier may be, it does have a slight advantage in the filter replacement section. The bundled Max2 filter set (HEPA + carbon) is modest and only requires one change annually. So, is 400 value for your money? Yes, but there are cheaper alternatives that might provide even greater price per performance ratio.
MRSP might not be feasible compared with other competitor's air purifiers, you can still find plenty of great deal available online. Amazon is our favorite spot as you can easily get Airmega 400 with 100-200 dollars knock off plus free shipping and 30 days return policy. Coway official website offers similar discount and easy payment deal as well but without the convenience of Amazon prime. There are also few retailers like Bed, Bath and Beyond, Kohls, and Walmart that carries the brand but none with the promotional edge as Amazon.

Airmega 400 VS the challengers

Airmega 400S

Airmega 400S

Identical in design, airflow delivery rate, CADR and purifying coverage. Airmega 400S comes with additional Wi-Fi connectivity for remote access and Amazon Alexa support. Incidentally, 400S is also the most expensive unit in Airmega lineup.
Airmega 300

Airmega 300

Cheapest in Airmega group but have to do without real-time pre-filter/ HEPA filter usage indicator, and Wi-Fi connectivity. Airmega 300 weaker airflow purifying coverage and lower all three CADR output are also unavoidable.

Coway AP-1512HH Mighty

Don’t need the super wide purifying coverage or limited airflow delivery rate, Coway Mighty "might" do the trick. At a fraction of Airmega 400 cost, you get decent filtration and airflow performance that can also cover for large room size.
Rabbit Air MinusA2 SPA-780N

Rabbit Air MinusA2 SPA-780N

Rabbit Air MinusA2 SPA-780A might not be the light to light air purifier against Airmega 400; it does well with a comprehensive 6-stage filtration that adds a medium and customizable filter in the pack. Adding a wall-mountable body, and interchangeable front panel in the bag, MinusA2 cheaper price tag might entice you to switch over.

 Good to know

Airmega 400 VS 400S

Both air purifiers share the same dimension, purifying coverage, airflow distribution, and clean air delivery rate. The only thing that separates these 2 air purifiers is Airmega 400 is cheaper and has a built-in timer to compensate for the lack of remote access while 400S is a Smart air purifier with Wi-Fi enabled feature for ioCare app and Amazon Alexa pairing.

Final thoughts on Airmega 400

Compiling the result of 160+ Amazon reviews, the first thing that impressed 85% of the 4-5 stars raters is Coway Airmega 400 wide purifying coverage can cover large spaces. Most people also agree on the Green True HEPA and activated carbon filters effectiveness against dust, pet dander, and tiny allergens. Design and usability are also on most users agenda, praising the air purifier modern approach with features like smart mode, air quality monitor, air vent seamlessly integrated. A mere 12% of the 1-2 stars raters thinks this air purifier is a waste of money and would rather go for a cheaper alternative like Winix. Some users also complained about the plastic smell after unboxing. In our humble opinion, 85% positive ratings is a strong indication that the air purifier works, while the 12% complains from the users can easily be rectified with buyer's return policy if they are not happy with the air purifier.

Verdicts and ratings

Build quality
Airflow delivery
Particle Filtration
Smoke Filtration
Airmega 400

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