Coway Airmega 250S review

The Coway Airmega 250S is a good purifier with a pricing problem. It cleans a typical bedroom or a modest living room (about 386 sq ft by our sizing), it looks more like a piece of furniture than an appliance, and it is one of the few Coways with Wi-Fi and voice control. The catch is that it only has three fan speeds, and the jump from speed 1 to speed 2 takes it from near-silent to clearly audible. At its $449 list price it is hard to justify; at the discounts it usually sells for, it makes more sense.

Where the 250S fits in Coway's lineup in 2026

The 250S has been on sale since late 2021, which makes it one of the older models in Coway's current range. It shares its body, fan and filter with two siblings: the plain Airmega 250, which has the same cleaning hardware and no Wi-Fi, and the 250 ART, a 250 with an artwork front panel. The "S" buys you the IoCare+ app, scheduling, voice assistants and remote alerts. Nothing else.

Two things changed around it. In March 2026 Coway launched the Coway Airmega Mighty2, which cleans almost the same room (240 CFM smoke CADR against the 250S's 249) for $269.99 with a cheaper filter. And on 2026-10-01 Coway's own store listed the 250S as sold out, although it remained available through Amazon and Target. A sold-out flag is not a discontinuation notice, but if you want a model Coway is actively pushing, that is worth knowing.

How big a room does it really clean?

Coway rates the 250S at 249 CFM for smoke, 261 for dust and 230 for pollen. At the 4.8 air changes per hour that keep up with allergens and smoke, and 8 ft ceilings, 249 CFM covers about 386 sq ft. Coway's headline "1,860 sq ft in 60 minutes" is one air change per hour, and its own four-changes-per-hour figure is 465 sq ft, so even the maker's stricter number is not far from ours.

HouseFresh's chamber test landed on the same 249 CFM at top speed, which is a good sign Coway's figure holds up. The harder number is what it does quietly. HouseFresh estimated just 91 CFM on speed 1, the only setting under 45 dBA. In a 12 x 15 bedroom (1,440 cubic feet) that is about 3.8 air changes an hour, which is fine for keeping a clean room clean overnight, not for clearing a pollen-heavy room fast. On top speed the same bedroom gets over 10 changes an hour. A 16 x 22 living room (352 sq ft) is within its range but will push it onto speed 2 or 3 whenever someone cooks.

The speed 1 to speed 2 problem

This is the 250S's defining weakness. HouseFresh measured, from 3 ft away:

Their room had 35 dBA of background noise, so Sleep and speed 1 are probably quieter than the meter shows. The issue is the gap: there is no setting between a whisper and a running-dishwasher level. Coway's own rating is 22 to 54 dB, measured differently, but the step between speeds is the same story.

In auto mode the 250S picks the speed for you, and Rapid mode holds it on high until the sensors read clean. If you mostly run it on auto in a living room, the gap matters less. If it sits next to your bed, expect it to spend nights on speed 1 and to sound obvious whenever auto kicks it up.

Filters, serial codes and the 3-year bill

The 250S uses one part: the Airmega 250/250S/250ART Max2 Filter (Coway SKU 3109144), a bonded HEPA and pelleted-carbon cartridge. Coway's filter page rates it for up to a year; the 250S product page says 6 to 12 months. Coway's store listed it at $89 on 2026-10-01, up from the $79 it showed earlier.

One trap: Coway's support site says the Max2 filter fits units whose serial number reads 02F9S or 02F9R after the first three digits. A unit showing another code, such as 02F5O, needs a different filter. Check the label before you order, especially if you are buying used.

Three-year cost at list price, assuming 24/7 use on speed 2 (22.01 W measured) and $0.17/kWh:

• Purchase: $449
• Filters: two replacements (the first is in the box) = $178
• Electricity: 22.01 W x 8,760 h = 193 kWh a year, about $32.78, or $98 over three years
• Total: about $725

If your filter light asks for a change every six months, as HouseFresh assumed, filters jump to five replacements ($445) and the total to about $992. Running on speed 1 instead cuts electricity to under $10 a year. For comparison, the Mighty2's equivalent three-year figure works out to about $456. Run your own numbers with the filter cost calculator.

Coway's US warranty excludes malfunctions or performance loss caused by non-genuine filters, so cheap third-party Max2 copies carry a risk beyond filtration quality. Our genuine vs compatible filters guide covers when that risk is worth taking.

The app and sensors: useful or gimmick?

The 250S has two sensors, one for particles and one for gases, so auto mode responds to cooking smells and not just dust. Air quality shows on a light bar that runs blue (good), green (moderate), yellow and red. There is no numeric readout on the unit; the app shows history instead.

The app does three genuinely useful things: schedules, remote on and off, and a timer (Coway's spec sheet lists the 1, 2, 4 and 8 hour timer as an app function). Voice control through Alexa or Google Assistant is a nice extra. The downside is reliability of the login. HouseFresh reported the IoCare app repeatedly logging them out, and owner reviews and app-store ratings point the same way. If you mainly want remote on and off, a smart plug with the non-Wi-Fi Airmega 250 gets you most of the way, since owners report Coway units can be controlled that way.

The catches

• Few speeds. Three fan settings plus Sleep, with a jump of nearly 14 dB between speed 1 and speed 2.
• Weight. At 20.5 lb, it is heavier than most purifiers of this output. Side hand holds help.
• Filter cost. $89 a year at best, more if the indicator asks for two changes.
• Age. It is a 2021 design. The newer Mighty2 has a laser particle sensor and a lower rated noise floor for less money.

Is it the right one for you?

Buy the Coway Airmega 250S if you want app scheduling and a slim, good-looking unit for a room up to about 386 sq ft, and you find it well under list. It suits a living room or home office where some fan noise on auto is fine.

For a bedroom, the Coway Airmega Mighty2 is the better Coway: same room size, quieter rating, and $19 a year cheaper to feed, though it has no app. If you want app control and a lower price, the Levoit Vital 200S-P (250 CFM) and the Winix 5530 (253 CFM) cover the same room for less. If your space is closer to 500 sq ft, step up to the Coway Airmega 350. Our best air purifiers for bedrooms list goes through the quieter options in this size class.