Coway Airmega 300S Review In 2022: Smart air purifier that works with Alexa!

Love everything about 300 yet wish it can be controlled remotely, Airmega 300S is your answer. With mirroring features, many users would appreciate the familiarity this purifying machine brings. Here comes the million dollar question. Does the additional Wi-Fi connectivity justify the premium price tag? Or would you rather spend the top up on Airmega 400? Let's go through the air cleaner spec and our detail review below.
online price (US)**
±749.00 $$$$$$$/ 7

(annual filter cost ±100)

** MRSP (Manufacturer's Suggested Retail Price)/ RSP (Retail selling price) is accurate at the time of posting.
^ Annual filter cost is calculated based on filter price and 12 hours of usage. Pricing could vary depending on air quality, usage frequency, and speed.
` The indicated online price guides as follows: $ = under $50, $$ = $50-100, $$$ = $101-200, $$$$ = 201-300, $$$$$ = $301-400, $$$$$$ = 401-500, $$$$$$$ = over $500.

Coway Airmega 300S Specification

ProductCoway Airmega 300S
13.6 x 21.2 x 13.6 in
(34.5 x 53.8 x 34.5 cm)
Weight21.4 lb (9.7 kg)
Coverage (up to)1,256 sq. ft. (117 m2)
Airflow speed
Dust free (CADR)260 cfm (442 m3/h)
Pollen free (CADR)260 cfm (442 m3/h)
Smoke free (CADR)260 cfm (442 m3/h)
Humidifying(H) 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
+- 99.99
Optional/ Addon
Noise level22 - 52 dB
Power usage level6 -57 W
Timer/ Scheduler1, 2, 4, 8 hours (App), Scheduler
SensorsPollution sensor
Auto mode
Air qualityAQ indicator
Filter change indicator
More color options
Wi-Fi/ BTBluetooth
Remote control
Child lock
Warranty5 years
Email/ Phone support

Key Features

  • 4-stage filtration
  • Equipped with Wi-Fi support (IoCare app/ Amazon Alexa)
  • 2 Permanent Pre-filter
  • MAX2 filter (True HEPA filter/ Activated Carbon filter)
  • 3 fanspeed (Low, Medium, High)
  • Dual sides air inlet
  • Pre-filter and HEPA filter indicator
  • Smart mode (Auto, ECO and Sleep mode)
  • Real-time air quality indicator (Good, Moderate, Unhealthy, Very Unhealthy)
  • Scheduler/ Timer via app (1, 2, 4, 8 hours)
  • 5 years warranty

Design And Usability

Coway Airmega 300S dimension
13.6 x 21.2 x 13.6 in
(34.5 x 53.8 x 34.5 cm)
Coway Airmega 300S weight
21.4 lb (9.7 kg)

A modern and quality air purifier from Coway. Airmega 300S is basically 300 with added Wi-Fi integration. Sharing the same dimension at 13.6 x 21.2 x 13.6 in/ 21.4 lb weight, the build quality is second to none. Front design is as clean as it gets with one prominent LED ring indicator. The air quality indicator will lit in blue and green when surrounding indoor air quality is good. Green and yellow when indoor air is moderate. Yellow and pink when indoor air is unhealthy. Finally, pink and red when indoor air is very unhealthy. Instead of just one back air inlet in typical design, 300S has dual air inlet that sucks air on both sides. Speaking of that, you will also find two handles on each side of the air purifier for easy transporting.

Airmega 300S control

Airmga 300S is unlike most air purifier that places its control panel at front. Its controls are located at the top black panel that is only accessible up close. Separated into two sections, On the left, you will find a Wi-Fi, Light, Pre Wash, and Max2 change button. Wi-Fi button enables connection to nearby Wi-Fi network. The Wi-Fi LED indicator will blink when there is no connection or undergoing pairing. Once the air purifier is connected to a Wi-Fi network, the LED light will stay constant. Next to it is the light button that activates/ deactivates AQ indicator light. The bottom two buttons (Pre Wash/ Max2) will lit once the filters require cleaning (Pre Wash) or change (Max 2). To reset the button indicator light, press and hold the buttons for 2-3 seconds. The small Light sensor is not a button, it is used to detects the intensity of the surrounding light. If the dark condition stays more than 3 minutes, Sleep mode will activate. This function can be overwritten if the air purifier is not in Smart mode (manual speed).

Continue to the right, you have a big Power button, a small Air speed/ mode button, and five small indicator light. The power button will obviously turn on/ off the air purifier (hold for 2-3 seconds). Airspeed/ mode button will cycle between the 3 fan speed, Smart mode, and Sleep mode. Here’s a secret function that many people are unaware of. The air purifier pollution sensor’s sensitivity level can be adjusted. First, press and hold to the light button, then press the Air speed/ mode button repeatedly until the desired sensitivity is selected. 1 fan bar = sensitive, 2 fan bar = normal, 3 fan bar = less sensitive.

Here is where the differences play it part. Airmega 300S comes with Wi-Fi support which allows you to manage your air purifier via IoCare App. Available in iTunes/ Google Play, pairing is straightforward for iPhone and Android phones. Through IoCare app, you can remotely control the fan speed or switch to Smart/ Sleep mode. There is also real-time air monitoring and Indoor/ Outdoor Air Quality Report. Timer and scheduler is a separate function. For timer, it comes with pre-set 1, 2, 4, 8 hours setting. For the scheduler, it is our favorite where you could program up to weekly schedule for the air purifier. Also works with Amazon Alexa where you could link it via devices like Amazon Echo. Standard list of voice command includes on/ off, Smart/ Sleep mode, fan speed, set timer, check filter life status and air quality.

To repeat, here are the standard features available in the air purifier. A 4 stage filtration, Smart mode (Auto/ Sleep/ Eco), and 3 fan speed. Wi-Fi enabled with IoCare app/ Alexa support. Separate pre-filter/ HEPA filter indicator based on runtime. Scheduler/ timer, air quality indicator. Lastly, 30 days satisfaction money back guarantee, and 5 years manufacturer warranty.

Airflow, Coverage, And CADR

Coway Airmega 300S coverage
Purifying coverage
1,256 sq. ft. (117 m2)
Coway Airmega 300S fanspeed

Comes in standard 3 speed + Smart/ Sleep mode, Airmega 300S has a decent airflow performance. At 1256 sq. ft. with 2 air charges every 30 minutes and 628 sq. ft. with 4 air charges every 15 minutes. There is still plenty of airflow punch even if you opt for the higher 4 air charges purifying speed. Pollution sensor functions accurately thanks to the adjustable sensitivity. Smart mode will automatically set the right speed based on surrounding air quality. Sleep mode would set to a lower speed for reduced noise and power. Great for residential home at living hall, basement or even bedroom (with Sleep mode).

BrandPurifying CoverageFan Speed
Alen BreatheSmart 45i800 sq. ft.4
Coway Airmega 400S1,560 sq. ft.3
Rabbit Air A3 SPA-1000N1,070 sq. ft.5
Winix AM90230 sq. ft.4
Blueair Classic 405430 sq. ft.3
Blueair Classic 205280 sq. ft.3
Coway Airmega 300S dust CADR
260 cfm (442 m3/h)
Coway Airmega 300S pollen CADR
Pollen CADR
260 cfm (442 m3/h)
Coway Airmega 300S smoke CADR
Smoke CADR
260 cfm (442 m3/h)
Airmega 300S CADR is also equally impressive at a rounded high 260 cfm for dust, pollen, and smoke. There are no differences in airflow performance VS 300, but there is a clear gap between the 400 series. Nonetheless, anything above 200 cfm would be good enough for indoor irritants.

Recommended Read

Filters And Performance

The familiar 4-stage filtration setup that can be found in every other Airmega models. Coway Airmega 300S works exactly like 300 with dual Pre-filter on both sides. Whenever the air purifier pulls air in, the pre-filter will block out the large particles. This leaves only the small particles alone the journey and that's where the True HEPA filter comes in. The Green True HEPA filter would trap allergens as small as 0.01 microns with an effective rate of 99.999%. With only smoke particles left, the last-stage Activated Carbon filter would kick in. At a successful rate of 99%, nearby smoke and odor contaminants will be well-contained. No ionizer is intact, so the filtration relies on the quality of the Max2 filters.

Noise And Energy Usage

Coway Airmega 300S noise level
Noise level
22 - 52 dB
Coway Airmega 300S power consumption
Power consumption
6 -57 W
Airmega 300S 22 - 52 dB noise level might not be the quietest air purifier around, is good enough for most occasion. It is considerably silent at sleep/ low speed and audible background noise at max speed. You can still use the air purifier in a bedroom although it's a little bit overkill for its capacity. Power consumption wise, 6 - 57 watts is not too shabby given the number of airflow output. Expect even lower consumption if this Energy Star unit engaged in Auto/ Sleep mode. Autonomous will prevent the fan speed from going above unless the air quality is not at an ideal level. Also, there is Eco mode where the motor fan will stop spinning when the air quality is good for at least 10 minutes.
Noise TypeDecibels
Coway Airmega 300S22 - 52 dB
Breathing10 dB
Rustling leaves20 dB
Whispering/ Quiet library30 dB
Light rainfall40-50 dB
Conversation50-60 dB
Vacuum cleaner/ Hair dryer/ Washing machine65-80 dB
City traffic80-90 dB

Pricing And Maintainence Cost

Coway Airmega 300S MRSP/ RSP
+- 749.00
Coway Airmega 300S annual filter replacement cost
Annual Filter Cost
+- 100
^ Replacement filters/ estimated cost
Coway Airmega 300S is not your typical budget-friendly model with cut-down specification. In fact, it is the complete opposite thus is even pricier than its peer model. Is the Wi-Fi enabled feature worth the extra dollar for an identical spec to Airmega 300? Only you can decide. On to maintenance, the mandatory filter change is not the most pricey in its class but is not cheap either. You need to replace the Max2 filter set on a yearly basis or when is depleted. When the time comes, the filter can be easily purchased online as availability is good.
Amazon is the place to be. Good news is you can get the air purifier at around 100 - 200 dollar off the retail price. Other than the huge discount, you will also enjoy free shipping and 30-days return policy. Alternatively, you can buy Airmega 300S from its official site with easy payment and free shipping perks. Lastly, consider retailers like Walmart, Kohls if the above option is not accessible.

Coway Airmega 300S VS The Challengers

Coway Airmega 300 Review

Coway Airmega 300

Drop the Wi-Fi connectivity and price will drop even further. As mentioned earlier, Coway Airmega 300 is the same air purifier as 300S but at around 100 dollars cheaper.
Coway Airmega 400S Air Purifier Review

Coway Airmega 400S

This is the highest range in Airmega series that also comes with Wi-Fi enabled. You'll get wider purifying coverage and higher CADR return. Plus there is an additional Graphite color option. Price is of course the highest, and that itself is undoubtedly the biggest obstacle.
Coway Airmega AP-1512HH Mighty Air Purifier Review

Coway Airmega AP-1512HH Mighty

Why not consider Coway top-selling model "The Mighty". Sure the specification does not match 300S raw power, it is still at respectable tier. More importantly, the much lower price is a lot easier to digest.
Rabbit Air MinusA2 Air Purifier Review SPA-780N

Rabbit Air MinusA2 SPA-780N

Cheaper to own and maintain. Rabbit Air MinusA2 SPA-780N is also Wi-Fi enabled and has the upper hand with a 6-stage filtration. Negative Ion Generator and a mountable frame body is also unique to MinusA2. On the downside, there is the weaker purifying coverage and CADR to content with.

Final Thoughts On Coway Airmega 300S

Coway Airmega 300S is a great, reliable air purifier as with the 300 model. Out of the 212 reviews around 65%4-5 stars reviewers in Amazon agrees with us. They particularly like the HEPA+Carbon filtration strength against allergens, smoke, and odors. Some users also like convenience features like air quality monitor and Auto mode. A few like the remote access and scheduler features in IoCare app. On the opposite end, a rather high 26% of 1-2 stars reviewers disagree. They are frustrated with the IoCare app that is either impossible to use or all in Korean language. A small group of users also commented on the ineffectiveness against odors irritants. Do note that the numbers do not reflect the true nature of the air purifier due to the lack of reviewers. To conclude, despite the majority of the users give positive feedback, do look out for future app update to fix any of the above-mentioned issues.


  • 4-stage filtration with wide purifying applicable area (at 2 air charges).
  • Use 2 Pre-filter on each side of the air purifier to traps dust and pet hair.
  • Highly-efficient allergen, smoke and odor filtration with the combined Max2 filter.
  • Convenience and highly practical Smart mode (Auto mode/ Sleep mode).
  • Separate Pre-filter and MAX2 filter lifespan indicator.
  • Remotely access the air purifier functions via IoCare app.
  • Real-time air quality display indicator.
  • Adjustable sensor's sensitivity level (sensitive, normal, less sensitive).
  • Reasonable Max2 filter replacement cost that only requires one yearly change.
  • Standard 5 years warranty.


  • Expensive based price that is close to the non-Wi-Fi 400 version.
  • Little learning curve on setting up Wi-Fi connectivity for first time user.
  • No built-in timer. Only accessible via Airmega app.
  • Lacks autonomous sleep mode activation (available in 400/ 400S).
  • Lacks real-time HEPA and Carbon filter change indicator (available in 400/ 400S).
  • No Ionizer within its filtration list.
Coway Airmega 300 Review

Max Fernandez

A loving father and a dedicated reviewer for airfuji.com with more than 1000 air purifiers under his belt. Max Fernandez is also one of the million patients currently suffering from asthma. Feel free to nudge him if you have any questions.
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