Search for Coway air purifier decibels and you will find a figure on every Airmega product page but one. That is more than most brands publish. What the pages mostly leave out is which fan speed each end of the range describes, and on three models Coway prints the unit as plain decibels rather than dB(A).
We read the US product page for every air purifier on Coway's store, cowaymega.com, and the user manual or one sheet wherever Coway publishes one. Nineteen current models carry a noise figure. This page lists all of them, explains what Coway's labels mean, and ranks each model only against others whose figure describes the same thing.
Our picks are listed above, with full specifications for each.
Every Coway spec table gives a range in the form "Noise Level: 22~52 dB(A)". Coway does not name the setting at either end, states no measuring distance, and names no test standard. Sixteen of the 19 ranges are in dB(A). Three, for the Halo, the Mighty2 and the Mighty Beige, print "decibels" with no weighting.
The low end is where the labels differ. Coway's pages and one sheets use three kinds of wording:
- Tied to Sleep Mode. The Halo page says the Night Sensor "drops to an industry-leading 17.8 dB(A) so you can sleep undisturbed."
- Tied to the lowest airflow speed. The ProX page says "At the lowest airflow speed setting, the noise level is an ultra-quiet 23 dB(A), similar to the subtle ticking of a watch". The Mighty AP-1512HH one sheet says "The noise level at the lowest airflow speed setting is a quiet 22dB(A), similar to the sound of a ticking watch."
- Not tied to a setting. Every other model prints a bare range and stops there.
Sleep mode and the lowest manual speed are different settings on every Coway manual we read that describes both, so a Sleep Mode figure and a lowest-airflow-speed figure describe different fan speeds. We never rank one against the other, and we never rank a figure printed as plain decibels against one printed as dB(A). Winix avoids the question by printing a single figure, the slowest speed; our Winix air purifier decibels page lists it for all 16 current Winix models and says where the manual makes that speed Sleep Mode.
The top end is never labelled. Coway's manuals say Turbo, or speed 3, is the fastest setting and that Turbo "may produce noise", so the top of the range most likely describes it, but Coway does not say so. We rank top figures against each other only within a size group, using Coway's smoke CADR as the size, because a bigger unit moves more air at full speed.
Low end tied to Sleep Mode
- Airmega Halo: 17.8 dB(A) in Sleep Mode, per the product copy; spec line 17.8~52.13 decibels; smoke CADR 253.3.
Low end tied to the lowest airflow speed, quietest first
- Airmega Mighty AP-1512HH: 22dB(A) at the lowest airflow speed setting, per the one sheet; but the one sheet's range is 24.4 ~ 55.1 dB(A) and the product page's is 24 ~ 53 dB(A); smoke CADR 233.
- Airmega ProX: 23 dB(A) at the lowest airflow speed setting; range 23 ~ 46 dB(A); smoke CADR 568.
Bare ranges in dB(A), lowest low end first
- Airmega 150: 19.98 ~ 48.3 dB(A); smoke CADR 153; 214 sq ft at 4.8 ACH.
- Airmega 160: 19.98 ~ 48.3 dB(A); smoke CADR 153; 214 sq ft at 4.8 ACH. The 160 is the 150 body in other colors, and its spec table matches the 150 line for line.
- Airmega 100: 20 ~ 48 dB(A); smoke CADR 108.
- Airmega 350: 21.5~54.7 dB(A); smoke CADR 352.
- Airmega 250: 22 ~ 54 dB(A); smoke CADR 249.
- Airmega 250S: 22-54 dB(A); smoke CADR 249. The Wi-Fi version of the 250, with the same spec table.
- Airmega 250 Art: 22 ~ 51 dB(A) on the product page, but 22-54 dB(A) on Coway's one sheet; smoke CADR 235.
- Airmega 300: 22~52 dB(A); smoke CADR 285.
- Airmega 400: 22~52 dB(A); smoke CADR 328.
- Airmega 400S: 22~52 dB(A); smoke CADR 328. The Wi-Fi version of the 400.
- Airmega 450: 23.6~57.7 dB(A), and in a second entry on the same page 23.69~57.71 dB(A); smoke CADR 439.
- Airmega MightyS AP-1512HHS: 24.4 ~ 53.8 dB(A); smoke CADR 210; 326 sq ft at 4.8 ACH.
- Airmega 200M: 24.4 ~ 55.1 dB(A); smoke CADR 246; 361 sq ft at 4.8 ACH.
- Airmega Aim: 38 ~ 56 dB(A); smoke CADR 66. The Aim is a desk-sized unit, and its low figure is 14 dB(A) above any other Coway.
Printed as plain decibels, lowest low end first
- Airmega Halo: 17.8~52.13 decibels, with the low end given as dB(A) in the product copy.
- Airmega Mighty2 AP-1512N: 19~50 decibels; smoke CADR 240.
- Airmega Mighty Beige AP-1512HHC: 24.5~54.9 decibels; smoke CADR 224.
Coway also sells the Airmega 50, a $79.99 unit whose page says "In Sleep Mode, the Airmega 50 is as quiet as a whisper" but prints no decibel figure, so it is not ranked here. The Airmega Icon, IconS, 230, 240, 300S and 450S still appear in Coway's filter and manual listings, but they no longer have product pages on the US store, so we leave them out too.
Top of the range, by size
For a small room, with a smoke CADR under 160, the Airmega 100 tops out lowest at 48 dB(A), then the 150 and 160 at 48.3 dB(A), and the Aim at 56 dB(A).
For a bedroom-sized unit, with a smoke CADR from 200 to 260, the firm figures in dB(A) run from the MightyS at 53.8 dB(A), then the 250 and 250S at 54 dB(A), to the 200M at 55.1 dB(A). We set aside the Mighty AP-1512HH, which prints 53 dB(A) on its page and 55.1 dB(A) on its one sheet, and the 250 Art, which prints 51 dB(A) on its page and 54 dB(A) on its one sheet. In plain decibels, the Mighty2 tops out at 50, the Halo at 52.13 and the Mighty Beige at 54.9. Our bedroom air purifier guide sets these beside other brands' units at the setting you sleep on.
For a large room, with a smoke CADR of 280 or more, the ProX tops out lowest at 46 dB(A), then the 300, 400 and 400S at 52 dB(A), the 350 at 54.7 dB(A) and the 450 at 57.7 dB(A). Our large-room air purifier guide sets the Airmega 400 beside other brands' bigger units.
What the gaps mean
Decibels are logarithmic. Roughly every 10 dB sounds about twice as loud, so the gap between 17.8 dB(A) in Sleep Mode and 52.13 decibels at the top of the same Halo is large: the top end sounds several times louder. A gap of 2 or 3 dB between two Coway models is small, and with no distance stated it may be no gap at all. The 450's two figures, 23.6 and 23.69 dB(A), differ by less than anyone could hear. Our decibel chart sets published appliance figures beside everyday sounds such as a whisper and a fridge.
Coway's quiet features, by their real names
Sleep Mode, and Smart Mode - Sleep. The Airmega 100 manual says "In the Sleep Mode, the fan speed is reduced for low noise operation in order not to interrupt the user's sound sleep", and that the buttons dim to 50% brightness. The 250 manual says sleep mode "minimizes the speed during operation for a quiet and pleasant environment." On the Halo and Mighty2, the manual says "If the product is set to Smart mode, Sleep mode is activated automatically so that it can reduce noise and power. If the surroundings of the product become dark for more than 3 minutes, sleep mode will turn on automatically." The 350 and 450 manuals say the same of auto mode, and add that sleep mode "will trigger off" after 5 minutes of light or any button press. On the 300, 400 and 400S, the shared manual adds a caution: "if the air speed is set manually or pollution level is above normal (in Smart mode), Sleep mode will not be activated automatically." The 300 page lists Sleep Mode as "Manual" and the 400 and 400S pages as "Automatic".
Silent mode. Only on the ProX. The manual says it "reduces airflow speed during operation to create a quiet and comfortable environment. It consumes less power and produces minor noise during operations." The ProX's automatic sleep mode "operates same as silent mode" and turns off every indicator but the silent mode light.
Eco mode. On the Mighty, Mighty Beige, MightyS and 200M, the manual says "When no pollution is detected for 30 minutes, the fan will automatically stop to save energy consumption." On the 350, Eco mode arrives by itself after 10 minutes of clean air in Auto Mode. A stopped fan is the quietest setting Coway offers, but it restarts when the sensor sees pollution.
Night Sensor and light sensor. The Halo's page calls it a Night Sensor that "detects darkness and automatically dims the display". The 350 and 450 pages say "the light sensor detects the surroundings and turns off the light to avoid disturbing bedtime." The 400 and 400S pages say the light sensor "measures brightness and automatically adjusts performance to optimize energy efficiency."
Light button and Button Mute. The 300, 400 and 400S manuals say the [Light] button turns "the air quality indicator and light on or off." The Halo manual lists four settings: "All lights on (AQI + LED display) → Night light → Night light off → All lights off". The 350 and 450 pages list "Button Mute for quiet operation", and the Halo manual says to "Press and hold the Mode button and Light button for 3 seconds to toggle the sound on or off." On the Mighty AP-1512HH, the manual says holding the IONIZER button for 3 seconds turns the air quality light on or off.
Auto, Smart and Rapid modes, and how they ramp. Every Coway auto mode raises the fan as the dust sensor reads worse air; the Mighty manual says it "Automatically optimizes the speed setting 1 through 3". The 250's Rapid mode goes further: "The product operates at maximum performance until the air quality is reduced to level 1." The ProX's Turbo mode runs "equivalent to Level 3 in manual mode" and, Coway says, "may produce noise". A burst of cooking smoke can take any of them to the top of the range in the night, so a fixed low speed or Sleep Mode is the quieter choice.
Quiet Mark. The Halo, Mighty2, 100 and 50 pages say the unit is "Quiet Mark certified for ultra-quiet operation." Coway does not publish the figure behind the certification, so we rank nothing on it.
Keeping a Coway quiet
Coway's manuals give similar placement advice across models. The 160 manual says "Use at least 20 cm away from walls or other objects on each side" and to install "at least 2 m away from TVs and other electronic items". The MightyS manual says to "maintain a distance of at least 20 cm from the walls or adjacent objects and 30 to 60 cm above the product." The 300, 400 and Mighty2 manuals say "Do not place the product where the both sides of product are blocked" and to use "a firm, flat, and dry surface that provides sufficient air circulation." Clean the washable pre-filter: the 250 Art one sheet says it "needs cleaning about every 2 weeks", and the Mighty manual says every 2 to 4 weeks. A blocked intake makes the fan work harder, and the 350 and 450 manuals warn that Turbo "may produce noise".
Three models give two figures in Coway's own documents. The Mighty AP-1512HH page says 24 ~ 53 dB(A), while its one sheet says 24.4 ~ 55.1 dB(A) and, on the same sheet, 22dB(A) at the lowest airflow speed. The 250 Art page says 22 ~ 51 dB(A) and its one sheet 22-54 dB(A). The 450 page prints 23.6~57.7 dB(A) and 23.69~57.71 dB(A) in two entries of the same specification section. We list every figure and give none of these three a "quietest" award on the lower one.
How Coway compares
This page ranks Coway models only against each other. For how they sit among other brands, on each maker's own published figures, see our guide to the quietest air purifiers. Since Coway, like most makers, states no measuring distance or standard, read our explainer on why decibel ratings rarely compare across brands before treating a gap of a decibel or two as real. Blueair has the same habit of disagreeing with itself: our Blueair air purifier decibels page found six product pages that give one figure in the spec table and another in the FAQ. For a maker that ties every figure to a numbered fan speed, see our Rabbit Air purifier decibels page.
How we chose
We read Coway's US air purifier collection and opened the product page for every model, plus the user manual and one sheet where Coway publishes them. We recorded each noise figure in Coway's words, with the setting Coway ties it to where it names one, and noted where a page and a one sheet disagree. We sorted the low figures into Sleep Mode, lowest airflow speed and unlabelled groups, kept the three plain-decibel ranges apart from the dB(A) ranges, and ranked top figures only within a size group, using Coway's own smoke CADR. Prices are Coway's US list prices on October 3, 2026.
We did not measure any of these purifiers. Every figure here is Coway's own, from its product pages, one sheets and manuals, and Coway states no measuring distance or test standard for any of them. Owners' rooms, floors and filters will change what they hear.
