Coway vs Blueair Air Purifiers: Comparing the Published Numbers

Last updated: October 21, 2026

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Coway and Blueair are two of the most frequently compared air purifier brands, and for good reason. Both make attractive, relatively quiet towers for living spaces, both publish CADR figures and both offer filter-change indicators. They differ in filtration design, coverage claims and extras. Comparing them well means looking past the headline coverage figure to the details.

All specifications below come from the makers’ product pages at the time of writing and may change. We have not tested these products ourselves, and we do not list prices, so confirm everything on the current pages.

Key Takeaways

• Both brands publish CADR; compare on smoke CADR and the same air-change basis, not headline coverage.
• Coway’s 400 lists a smoke CADR of 328 and Blueair’s 311i+ Max lists 339, per their pages.
• Ionization appears in some designs from both brands; check ozone information and the manual.
• Confirm all numbers on the makers’ current product pages.

Pets, Allergies and Smoke With These Brands

For pets, the Coway 400’s washable pre-filter is helpful for hair, and both brands use carbon layers to address odors, in amounts that vary by model. For allergies, the particle filter and correct sizing matter most; run the unit continuously on a low or medium setting, keep windows closed in high-pollen seasons and wash bedding regularly. For smoke, the smoke CADR is the key number, and carbon capacity influences odor removal. After a smoke event, inspect filters and replace them sooner.

If someone in the household has asthma or severe allergies, follow the doctor’s advice. A purifier is one measure among several, along with cleaning, ventilation and source control.

A Quick Checklist Before Buying

Write your room size and compute the target smoke CADR. Pull the smoke CADR for each candidate from the maker’s page. Convert coverage claims to the same air-change basis. Check the filter type, life and cost per year. Check noise at the speed you will use. Check ionization settings and ozone information. Decide whether you want an app. Check the warranty.

Then choose the model that meets your CADR target quietly, with filters you can afford and features you will use. Keep the manual, set a reminder for filter checks and confirm all specifications on the current product pages, because both brands update their lineups regularly.

Small Rooms: Where the Smaller Models Fit

Not every home needs a large tower. For a bedroom of 150 to 250 square feet, smaller models from either brand can be a better fit, quieter at low speed and easier to place. Coway’s Airmega 150 lists a smoke CADR of 153 and a stated 214 square feet at 4.8 air changes per hour, with a noise range starting near 20 dB(A), and Blueair offers smaller Blue Pure units too. Check the smoke CADR and the noise of each smaller model before you decide.

If your room is on the larger side of that range, consider stepping up one size so you can run the unit at a lower speed. Remember that the smallest unit is not always the cheapest to run once filter costs are included. Confirm everything on the current product pages and keep your decision tied to your own room measurements.

Air Purifiers to Compare

The table below lists purifiers from our affiliate partner. Compare smoke CADR, room size ratings and filter details across brands, and check each maker’s current pages.

Noise, Controls and Extras

Coway lists noise of about 22 to 52 dB(A) for the 400 and about 24 to 55 for the 200M. Blueair lists about 23 to 50 dB for the 311i+ Max. The differences are small on paper; real-world noise depends on the speed you need and your room.

Coway models offer auto mode and air quality lights; the 400 is not app-enabled, per its page. The Blueair model lists Wi-Fi control, ENERGY STAR certification and filter tracking.

Coway vs Blueair at a Glance

The table below summarizes the published figures. Confirm them on the makers’ sites.

The Published Numbers

Coway lists the Airmega 200M with a smoke CADR of 246 and the Airmega 400 with a smoke CADR of 328. Its coverage figures use different air-change bases: 361 square feet at 4.8 air changes per hour for the 200M and 1,560 square feet at 2 air changes per hour for the 400. Blueair lists the Blue Pure 311i+ Max with a smoke CADR of 339, a recommended room size of 525 square feet and noise from about 23 to 50 dB.

At first glance the Coway 400 and the Blueair 311i+ Max have similar smoke CADRs of 328 and 339. The difference between the Coway 400’s 1,560 square feet and the Blueair’s 525 square feet is mainly the air-change assumption, not a difference in how much air they clean.

Filtration Approaches

Coway’s 400 uses a washable pre-filter with a combined carbon and HEPA set rated for about a year, and the 200M uses a pre-filter, a deodorization filter and a HEPA filter, plus a bipolar ionizer. Blueair’s HEPASilent approach, as described by Blueair, combines mechanical filtration with an ionizer that charges particles so they stick to the filter media, and Blueair states its ozone emissions are tested to meet US, EU and China requirements. Blueair lists filters of up to nine months for the 311i+ Max.

Both brands involve ionization in at least some designs. The EPA advises against ozone-emitting air cleaners, so look for independent ozone information, such as California certification, and check the manual for ways to switch features off.

Putting the Coverage Claims on One Basis

Coway states 1,560 square feet for the 400 at 2 air changes per hour. At the standard 4.8 air changes per hour used by AHAM, the same unit would be rated for roughly 650 square feet by simple scaling of that claim, and about 490 square feet by the two-thirds rule applied to its 328 smoke CADR. Blueair’s 525 square feet for the 311i+ Max is in the same neighborhood as the latter.

This shows why you should never compare room size claims from different brands directly. Use smoke CADR, compute air changes for your room, and decide how quickly you want the air cleaned. For a 400 square foot living room, either unit would deliver more than 5 air changes per hour at its top speed and could run slower for quiet.

Filters and Upkeep

Coway’s washable pre-filter on the 400 is a practical feature for homes with pets and dust; you clean it and keep going. The combined carbon and HEPA set is listed at about a year, and Coway includes two sets with the unit. Blueair lists filters of up to nine months, depending on fan speed, use and pollution, and offers different filter types such as particle and carbon, AllergenBlock and SmokeBlock for its models.

Check the replacement cost and availability for the exact model you choose. Look for how the filter indicator works, and inspect filters yourself, particularly after smoke or heavy use. Keep a spare and write the date on each filter.

Noise and Sleep

Both brands list low-end noise in the low-to-mid 20s dB. Both have sleep or night behavior, and both offer ways to dim lights, though specific options vary by model. In a bedroom, the larger units run quietly at low speed because they have capacity to spare. Place the unit a few feet from the bed, on a stable surface and with clear space around it.

Try the unit during the first nights, and adjust placement. If auto mode wakes you, switch to a fixed low speed.

Smart Features and Controls

Blueair’s 311i+ Max lists Wi-Fi control, an app and filter tracking, while the Coway 400 page notes it is not Wi-Fi or app-enabled but has auto mode, an air quality light and filter indicators. If you want remote control and schedules, choose a model with an app; if you prefer a simple appliance, the Coway approach may suit you.

Whichever you choose, make sure the unit works well with its physical controls and consider the privacy aspects of connected devices.

Which Should You Choose?

If you prefer a washable pre-filter, auto mode with air quality lights and an appliance without an app, a Coway Airmega is a strong candidate. If you want published room-size ratings in the AHAM style, Wi-Fi control and a quiet low speed, a Blueair is worth a look. In both cases, shortlist the specific model, compute your own numbers and compare filter costs.

Always verify the current specifications and ionization details on the makers’ pages, and read the manual before you use any optional feature.

How to Choose

1. Convert coverage claims to the same air-change basis.
2. Size by smoke CADR for your room.
3. Check ionization and ozone information.
4. Compare filter life and cost.
5. Avoid ozone generating or ionizer modes; the EPA advises against ozone-emitting air cleaners.

Honest Limits

• This guide uses manufacturer information and public guidance from the EPA and AHAM, not our own lab tests.
• Features and room ratings change between model years, so confirm on the listing before you buy.
• A purifier is not a medical device and does not replace medical advice or treatment.

Who Should Skip This

When to See a Professional

Compare on smoke CADR and a common air-change basis, then choose on noise, filters and features.

Frequently Asked Questions

Which has the higher CADR?

The pages we reviewed list 328 smoke CADR for the Coway 400 and 339 for the Blueair 311i+ Max.

Why do the room sizes differ so much?

They use different air-change assumptions. Convert to the same basis.

Which is quieter?

Both list low-20s dB at the lowest speed; compare at the speed you need.

Do they use ionizers?

Coway lists a bipolar ionizer on the 200M; Blueair describes an ionizer in HEPASilent. Check your model.

Is there a washable pre-filter?

The Coway 400 has one. Check Blueair models individually.

Which has an app?

The Blueair model we reviewed lists Wi-Fi; the Coway 400 does not.

How long do filters last?

Coway lists about a year for the 400; Blueair up to nine months for the 311i+ Max.

Is one better for pets?

A washable pre-filter helps; check each model.

Are they ozone-free?

Check each maker’s ozone information. The EPA advises against ozone-emitting air cleaners.

Where do I confirm specs?

On the makers’ product pages.

Bottom Line

Coway and Blueair offer similar smoke CADR in their larger towers; the headline coverage difference is mostly an air-change assumption.

Compare on a common basis, check ionization details and confirm specifications on the makers’ pages.

Related reading: sens,fan,bed

Sources: EPA, Guide to Air Cleaners in the Home; AHAM Verifide.