Coway Airmega 400 Air Purifier
- Up to 3,120 sq. ft. cleaned in 60 minutes
- Pre-filter, active carbon and HEPA stages
- 99.97% of 0.3 micron particles
- Smart Mode adjusts fan to sensed air quality
- Eco Mode fan off after 30 clean minutes
- Sleep Mode after 3 dark, clean minutes
Last refreshed Sep 8, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A large room purifier with layered filters and sensors that run the fan on their own. Noise, power draw and filter life are not listed.
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ASIN: B01C9RIACGModel: Airmega 400Category: HEPA Air Purifiers
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Overview
Coway built the Airmega to clean large spaces with three filter stages: a pre-filter, an active carbon layer for odor and volatile organic compounds, and a HEPA filter for pollen and allergens. Light and pollution sensors read the room and set the fan on their own.
Large room coverage and hands-off sensor modes are the reason to buy. Noise levels, wattage and filter replacement intervals are not listed, so upkeep is hard to judge before purchase.
Who it's for
Open plan homes and big living rooms where allergens and odors build up suit it. Shoppers who need a small desk unit or a listed noise rating should keep looking.
Pros and cons
- Three stage filtration
- Carbon layer reduces odor and VOCs
- Fan adapts to sensed air quality
- Eco Mode stops the fan in clean air
- Noise, wattage and filter life not listed
- Eco Mode pauses air circulation entirely
Performance notes
Air passes the pre-filter, then the carbon layer, then the HEPA filter, so each stage handles a different kind of pollutant. In Smart Mode the pollution sensor raises or lowers fan speed, which ties noise and energy use to how dirty the air is. Eco and Sleep modes cut the fan back when the room stays clean or dark.
Specifications
| Brand | Coway |
|---|---|
| Model | Airmega 400 |
| Floor Area | 3,120 sq. ft. in 60 minutes |
| Filter Type | Pre-filter, active carbon filter, HEPA filter |
| Particle Retention Size | 99.97% of 0.3 micron particles |
| Contaminant Filtration Capability | Pollen, allergens, volatile organic compounds, odor |
| Special Features | Smart Mode, Eco Mode, Sleep Mode, light and pollution sensors |
Frequently asked questions
How do you look after the Coway Airmega filters?
The listing names a pre-filter, an active carbon filter and a HEPA filter but gives no cleaning or replacement schedule. Check the Coway manual for intervals.
Is the Coway Airmega quiet enough for a bedroom at night?
Sleep Mode reduces noise and power use once the light and pollution sensors find the room dark and the air clean for 3 minutes. No decibel figure is listed.
Does Eco Mode turn the Coway Airmega off?
The fan turns off after the air stays purified for 30 minutes in Eco Mode, then restarts when pollution is detected.
Does the Coway Airmega remove odors?
Yes. The active carbon filter is listed as reducing odor and volatile organic compounds.