Coway Airmega 400S Review: Whatever you need in this Smart enabled air purifier!

Last updated on April 27th, 2020

The starters

Simplicity meets modern architecture. Coway Airmega 400S manage to perfect the art of design with its seamless dual side air inlet. The 14.8 x 22.8 x 14.8 in size and 24.7 lb weight is considerably compact for its category if you discounted the four fixed legs. Build quality is top-notch that does not seem to be any signs of ozone off-gassing or air by-pass. Upfront, there is a LED ring AQ indicator with real-time (every minute) air pollution update. Up to four different colors will be shown on the air quality status. Starting from Good (Blue and green), Moderate (Green and yellow), Unhealthy (Yellow and pink) to Very Unhealthy (Pink and red). Finally, to lift or transport the air purifier around, simply hold on to both sides of the handles.

Controls are located at the top black panel that separates into two sections. On the left side, you will find a Wi-Fi button, Light button, Pre Wash button, and Max2 change button. Touching the Wi-Fi button connect the air purifier to a Wi-Fi network. The Wi-Fi LED indicator will start blinking when the pairing is in progress. Once a stable connection is established, the LED indicator will stay constant. The light button will turn on or off the air quality indicator light. Pre Wash button will shows the pre-filter cleaning cycle at 5 levels: 100%, 80%, 60%, 49%, 20%, and 0%. Once the button is lit, you will need to clean the pre-filter. To reset the Pre Wash filter Lifetime notifications, touch and hold the button for 2-3 seconds. The above steps apply to Max2 Change button as well. Instead of cleaning the filter, you will need to replace the Max2 filter. Light sensor function by detecting the intensity of ambient light. When the air purifier is in Smart mode and surrounding is in pitch black for 3 minutes, Sleep mode will activate.

Moving to the right side, you have the big main Power button that is self-explanatory. Touch the button once to turn on the air purifier, touch and hold the same button again for 2-3 seconds to turn it off. To manage the fan speed or purifying mode, either touch or swipe your finger upward or downward on the curve bar. One more secret function that most people didn’t know unless they read the manual (how many of you does that). you can adjust the sensor’s sensitivity by holding on the Light button +Smart bar. Continue by selecting one of the fan speed (speed 1 = sensitive, speed 2 = normal, speed 3 = less sensitive). Overall, all buttons are responsive, clearly labeled with dedicated indicator light.

Like 300S, the Wi-Fi enabled feature that allows you to control the air purifier at any place via IoCare app. Pairing is easy for both Apple and most Android phones so long you have strong Wi-Fi connectivity. We did encounter some issues with some lower end model (Huawei to be exact) that requires few retries. Upon successful connection, you can access features like timer, speed, Smart Mode, and scheduler. Highlights would be on the scheduler that allows you to program weekly activities. You can also access indoor/ outdoor air quality report and Real-time Air Monitoring.

Airmega 400S also works with Amazon Alexa where you could control specific functions. The standard list of voice command includes on/ off, switching mode, fan speed, timer, check filter life, and air quality.

Briefly go through other key specification again. A standard 4-stage filtration, 3 fan speed with Smart mode (Auto/ Sleep/ Eco). Wi-Fi enabled for Airmega’s IoCare app and Amazon Alexa support. Pre-filter/ MAX2 life-time indicator (actual filter real-time usage lifespan). Lastly, air quality indicator, 30 days money back guarantee and 5 years warranty.

Airflow, speed, and CADR

Despite the lack of Wi-Fi function, Airmega 400 never skim on airflow performance. Expect the same airflow delivery and applicable area with the S variant. 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 output. Adding an adjustable pollution sensor, Default Smart mode is there for autonomous purifying. Sleep mode will reduce noise and speed intended for night use. Speaking of night use, 400 can be used in bedroom or even living hall as it has the capacity for large room size. CADR is also equally impressive as the purifying coverage. Overall dust, pollen, and smoke have an outstanding 350 cfm figures. Significantly higher than most air purifiers CADR output within its segment. Based on the figures itself, 400S would have no problem handling heap of dust and allergens. Same goes with indoor smoke and odor pollutants.

What’s inside count

Airmega 400S uses the same 4-stage filtration setup that is proven against the test of time. Essentially a dual pre-filter plus Max2 filter bundled (True HEPA and Activated Carbon). Each pre-filter would cover both sides of air inlet for incoming airborne contaminants. With large particles out of the way, Green True HEPA filter would focus on microbes allergens. Anything that is 0.3 microns or bigger with not be able to bypass the HEPA filter excluding gas particles. That job belongs to Activated Carbon filter that will absorb nearby smoke and odors. There is no optional Ionizer included in the filtration list; Not a big miss for some.

Keep it down

22 - 52 dB noise level is the same as 400 model. Reasonable but not overly silent at low speed and low to normal conversion noise level at max speed. Usable in bedroom if you crank it in Sleep mode. The 6 - 66 watts power consumption is in an identical pattern with noise. Minimal consumption rate at low speed and high consumption rate at medium/ high speed. To further enhance the eco-friendliness, there is ECO mode by will activate automatically. The air cleaner would shut down the fan when the room air quality is good for at least 10 minutes. Auto mode would also prevent any energy wastage where it would only run at a higher speed when requires.

At what cost

Coway Airmega 400S air purifier is the highest in the brand hierarchy hence it is the costliest. We do think it's worth every penny you paid but some features are not critical to purification. If that's the case, maybe it's time to consider the smaller 300S or other equivalent models. Annual filter replacement cost is more reasonably priced with plenty of availability. Both 400 and 400S uses the same Max2 filter set.

Airmega 400S VS the challengers

Verdicts and ratings

Other Airmega Air Purifiers