Coway Airmega 300S Review: Smart air purifier that works with Alexa!
Airmega 300S Specification
Product | Airmega 300S |
Dimension | 13.6 x 21.2 x 13.6 in (34.5 x 53.8 x 34.5 cm) |
Weight | 21.4 lb (9.7 kg) |
Fanspeed | 3 |
Coverage (up to) | 1256 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 | |
Filtration | 4-stage |
Pre-Filter - Lifespan - Replacement cost ($) | Pre-filter (2 pack) Permanent +- 25 |
HEPA filter - Lifespan - Replacement cost ($) | 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 level | 22 - 52 dB |
Power usage level | 6 -57 W |
Timer/ Scheduler | 1, 2, 4, 8 hours (App), Scheduler |
Sensors | Pollution sensor |
Auto mode | |
Air qualityAQ indicator | |
Filter change indicator | |
More color options | |
Wi-Fi/ BTBluetooth | |
ENERGY STAR | |
Remote control | |
Child lock | |
Warranty | 5 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
Pros
- 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.
Cons
- 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.
The starters
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.

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, speed, and CADR
What’s inside count
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 0.3 microns with an effective rate of 99.97%. 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.Keep it down
At what cost
^ Replacement filters/ estimated cost
Airmega 300S VS the challengers

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.
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 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.