Coway Airmega 300 vs 400. Which Airmega is better?
Coway has a number of air purifiers in their airmega series that include; the coway airmega 300, coway airmega 300s, coway airmega 400 and coway airmega 400s to mention but a few. In this article, we shall be looking specifically at the coway airmega 300 vs 400. We detail what sets them apart and which air purifier is better for you.
Summary of Coway Airmega 300 vs 400
This section quickly runs you through our top pick for this comparison and why. Both air purifiers would certainly perform well even if you choose to go with either of them. But our winner for this comparison is the Coway Airmega 400.
Why the Coway airmega 400 is the better purifier?
- Has an automatic sleep mode
- Large room coverage of 1560 sq feet
- Better clean air delivery rates
- Overall better performance
You can also check out the Coway Airmega 300 if the coway airmega 400 is above your budget. This is because the main difference between the two air purifiers is the room coverage (1256 sq ft), slightly lower performance and the fact that its sleep mode is manual.
Differences in the coway airmega 300 vs 400
Room Coverage
As with all air purifiers, the space they can effectively purify is a big factor whenever making a choice between purifiers.
In this coway 300 vs 400 comparison, the difference is a bit clear. The Coway airmega 400 covers 1560 sq feet while the coway 300 can cover up to 1256 square feet.
That’s a difference of around 300 sq feet. Some air purifiers have been designed to actually cover just this difference.
Therefore, the coway 400 is the better purifier in regards to room coverage.
Sleep mode
Even though they both have sleep mode, the difference is in how the sleep mode functions. The coway airmega 400 has a light sensor that allows sleep mode to be automatic. That means, the light sensor can detect when it gets dark and automatically turn on the sleep mode.
While in the Coway Airmega 300, the sleep mode can only be turned on by manual action. This means you have to manually activate it using the sleep mode button found on the unit.
With sleep mode, the coway arimega reduces how much power it consumes. It also reduces the amount of noise the unit makes so that you can sleep undisturbed.

Performance (Clean Air delivery rate)
Coway 400 has a better clean air delivery rate when compared to the Coway 300. This means that for a set period of time, the coway 400 will purify air faster than the coway 300.
The coway airmega 300 features the following clean air delivery rates;
- 285 for Smoke
- 306 for Dust
- 339 for Pollen
While the coway airmega 400 has the following clean air delivery rates;
- 328 for Smoke
- 328 for Dust
- 400 for Pollen
As you can see above, the Coway 400 performs significantly better than the coway 300.
Power consumption
The last difference in the coway 400 vs 300 is the power consumption.
The Airmega Coway 400 has a rated consumption of 66W while coway airmega 300 has a power consumption of 57 watts.
The Coway Airmega 400 consumes more power than the Coway 300. This can be attributed to the fact that it is a more powerful machine and hence consumes more energy.
Similarities in the Coway airmega 400 vs 300
Air Intake
Both the coway 300 and coway 400 intake air from both sides of the unit and push air from an outlet at the top of the unit. Because of this double air intake, the air is purified much faster across the room.
3 stage filtration System
Both the coway airmega 300 and the coway airmega 400 feature the standard 3 stage filtration system.
This 3 stage filtration includes a pre-filter, a true HEPA filter and carbon filter. The special thing about these Coway Airmega models is that the carbon filter and HEPA filter are combined into one filter. The combination is referred to as a Max2 filter. This combination into a single Max2 filter makes maintenance easier.
The Max2 filter removes airborne particles as small as 0.03 microns in size. It also removes a whole host of odors and volatile organic compounds from the air.

Smart Auto Mode
The smart auto mode function allows the coway airmega to adjust according to the room’s air quality. If the air quality is bad, it will increase the fan speed. If the air quality is moderately okay, it will also choose the most optimal fan speed.
The smart operation of the coway 400 and 300 makes the unit more efficient in how it consumes energy. It also means the unit will use less energy while still performing efficiently.
Smart Eco Mode
The smart eco mode is an energy conservation feature that is actually pretty cool. It is also not commonly found in other air purifier brands.
This is how it works. If the air quality remains more or less clean for a period of 10 minutes, the unit will automatically turn off its fan. This response helps to conserve energy and prevent unnecessary power consumption.
The smart eco mode is present in the both the coway airmega 400 and coway airmega 300.
Air Filter Indicator
Both units have two air filter indicators. The air filter indicators include; a pre-filter indicator and a max2 filter indicator.
The pre-filter indicator notifies you when the pre-filter becomes too dirty that it can no longer operate efficiently. When this indicator lights, you should remove the pre-filter and clean it.
The Max2 filter indicator also serves a similar function. It notifies you when the max2 filters are clogged and need replacement. Therefore, when this indicator lights, you should replace the Max2 filter as soon as possible.

Air Quality Monitoring
Both air purifiers have an air quality monitoring feature. This feature will monitor the quality of the air in real-time and display the air quality using an LED ring.
This LED ring is found at the front face of the unit. It keeps changing color according to the detected air quality. The units use a pollution sensor to detect and indicate the indoor quality via the LED ring.
Therefore, you will always be informed of the status of the quality of your indoor air, every passing minute.

Timer Mode
Last on our list of similarities in the coway 400 vs 300 is the Timer mode.
This timer mode allows you to easily schedule operation of the unit for as long as you want. So let’s say you wanted the unit to run for 1 hour, you can easily do this using the timer mode feature.
The coway airmega 300 and 400 both allow you to schedule the purifier to run for 1, 4 or 8 hours of use.
Coway Airmega 400 review
Coway Airmega 400 is an air purifier with a 3 stage filtration system. This filtration system includes;
A pre-filter to capture large particles, a True HEPA filter for the smaller particles and an activated carbon filter for odors and Volatile Organic Compounds.
Though, for the Airmega 400, the carbon filter and True HEPA filter have been combined into one filter. This combination is known as the Max2 filter. This Max2 filter reduces up to 99 percent of fumes, volatile organic compounds and particles as small as 0.03 microns found in the air.
For rooms that are as large as 1560 square feet, the Coway Airmega is your go to air purifier. It guarantees at least two air changes per hour for a 1,560 square foot room.
It also has a number of modes that are quite handy in the overall operation of the air purifier.
- Auto Mode; that puts the air purifier in a state of always monitoring the rooms’ air quality. So if the air quality dips, it will automatically start purifying the air. These adjustments in fan speed are always optimized for the task at hand.
- Automatic Sleep mode; Using the light sensor on this device, the unit can easily detect when its night time or lights out and immediately activate sleep mode.
- Timer Mode; In this mode, the user can determine for how long they want the air purifier to run for. This can be for 1 hour, 2 hours, 4 hours or even 8 hours.
The Airmega 400 has two filter indicators. One indicator indicates when the pre-filter needs to be washed. The second filter indicates when the Max2 filter needs to be replaced.
Finally, it has a consumption of 66 watts and is energy efficient.
Coway Airmega 400 Pros
- Easy to setup and operate
- Eco-mode for saving power
- Auto mode
- Washable pre-filter
- Has automatic sleep mode
- Air quality Indicator
- Powerful unit
- Has an indicator to remind you to wash the pre-filter.
- Also has a Max2 filter change indicator
Coway Airmega 400 Cons
- A bit heavy and not easy to move around
- No WIFI capability
Coway Airmega 300 review
The coway Airmega 300 is a powerful air purifier that can cover rooms as big as 1,256 square feet. Based on its recommended room coverage, it can do at least two full cycles of purification per hour.
It features a Max2 filter that is a combination of an activated carbon filter and True HEPA filter. This Max2 filter forms part of the Coway Airmega 300 3 stage filtration. The other part of this 3 stage filtration is a washable permanent pre-filter meant to capture the larger airborne particles.
The Airmega 300 also has an air pollution sensor that constantly monitors the air quality indoors. The sensor communicates the air quality status in real-time via its LED ring.
Coway 300 also has an auto mode whose function is to allow the air purifier automatically adjust its fan speed depending on the air quality of the room. It further has a sleep mode that ensures the machine operates quietly without making any irritating noise. The noise level is quite low at low speeds averaging around 22 dB. The maximum noise it makes at its highest setting is around 43 dB. These noise levels are very tolerable.
Airmega 300 is an energy efficient machine and consumes only 57 watts. This consumption is quite low considering how powerful the machine is.
To top it off, the Coway 300 also has a Timer that allows you to dictate for how long you want the machine to run. It also includes a filter indicator for both its pre-filter and Max2 filter. The indicator will notify you when it’s time to wash the pre-filter or to replace the max2 filter.
Coway Airmega 300 Pros
- Has auto mode
- Quick setup and easy to use
- Contains Sleep mode function even though its manual, it’s still a plus
- Eco mode for saving energy
- Has an LED indicator to display air quality in real-time
- Indicator to notify you when it’s time to wash the pre-filter
- Also has filter replacement indicator for the max2 filter
Coway Airmega 300 Cons
- Large and heavy
- Does not have WIFI support
Comparison table coway airmega 400 vs 300
Feature | Coway Airmega 400 | Coway Airmega 300 |
Room Coverage | 1,560 ft2 | 1,256 ft2 |
Auto Mode | Yes | Yes |
Eco Mode | Yes | Yes |
Sleep Mode Type | Automatic | Manual |
Noise Level Range | 22 – 52 dB | 22 – 52 dB |
Energy Use | 66W | 57W |
Wifi Capability | No | No |
Conclusion coway airmega 300 vs 400
In conclusion, the clear winner of the coway arimega 300 vs 400 is the Coway Airmega 400 air purifier.
This is because it offers better value in terms of performance and operation. It has better room coverage, better performance and a better clean air delivery rate. It also has an automatic sleep mode making the feature even more convenient to use. And even though it consumes a bit more power, it makes up for that by offering more in terms of performance and operation efficiency.
But this doesn’t mean that the coway airmega 300 is a bad choice. It simply means that the coway airmega 400 just offers more.
You can still check out the coway airmega 300 if you have a smaller sized space in the range of 1256 sq. ft. and below.
Frequently asked Questions
How do you clean the pre-filter when it gets dirty?
It is easy to clean the pre-filter. You can vacuum it or clean it using a soft brush
The prewash light won’t turn off even after I am done cleaning the pre-filter?
You should hold down the pre-filter light button until you hear a beeping sound and the unit turns off.
This action will reset the pre-filter wash counter.
Does either the coway airmega 400 or coway airmega 300 have a remote control?
No, neither of the two units has a remote control
What is the difference between the Airmega 300 and the Airmega 300s?
The only difference is that the Airmega 300s is Wifi enabled & can be controlled using a smartphone app.
What is the difference between the Airmega 400 and the Airmega 400s?
As with the 300 and 300s, the only difference here is that the 400s has Wifi capability. So you can connect the unit to your smart phone using a mobile application.
This is not possible with the Airmega 400 because it is not Wifi enabled.
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