Coway Airmega 250 vs Blueair Blue Pure 211i Max vs Coway Airmega 400S
Compare three larger-room purifiers whose room claims use 4, 4.8 and 2 air changes per hour. Named particle CADR, filters and app control are covered for the exact US packages.
The decision in brief
How the options differ
The three published room areas are not on the same basis: Airmega 250 lists 465 sq ft at 4 ACH, Blue Pure 211i Max lists 674 sq ft at 4.8 ACH and Airmega 400S lists 1,560 sq ft at 2 ACH. Blue Pure 211i Max has the highest named particle CADR of the three; Airmega 400S is the only Coway here with documented app control and uses two Max2 filters. Airmega 250 app control is not established. None of these published figures is a measured result for your room.
Review due. Check the current source before buying.
By CompareFoundry · Published · Editorial review · Manufacturer documentation, not hands-on testing.
The buying guide
Package and specification details
Compare named CADR before any room figure
Airmega 250 lists smoke, dust and pollen CADR of 249, 261 and 230 CFM. Blue Pure 211i Max lists 435, 452 and 450 CFM. Airmega 400S lists 328, 328 and 400 CFM. The Blueair figures are the highest for every named particle, with the largest gap on smoke. These are manufacturer ratings in cubic feet per minute, usually measured at the highest fan setting; they are not our measurements and do not describe a quieter setting.
Review due. Check the current source before buying.
Read each room area with its own air-change rate
Coway pairs 465 sq ft with 4 ACH for Airmega 250, Blueair pairs 674 sq ft with 4.8 ACH, and Coway pairs 1,560 sq ft with 2 ACH for Airmega 400S, whose manual also gives 780 sq ft at 4 ACH. Comparing 1,560 directly with 674 or 465 would mix different rates. Both Coway claims assume an eight-foot ceiling and maximum fan speed. Measure the room, note the ceiling height and decide which rate you want before trusting the largest number.
Review due. Check the current source before buying.
Check the filters, power and controls you will live with
Airmega 250 uses one Max2 filter (3109144); Airmega 400S uses the two-piece 400/400S Max2 set (3104756), one per side, and is not interchangeable with the 300-series set. Blue Pure 211i Max uses its Particle & Carbon filter, with a washable fabric prefilter in the box. Listed power is 64 W, 46 W and 66 W respectively. App control is documented for Blue Pure 211i Max and Airmega 400S; it is not established for Airmega 250, which is a different product from the 250S.
Review due. Check the current source before buying.
Common questions
Is Airmega 400S three times the purifier of Airmega 250 because it lists 1,560 sq ft?
No. The 1,560 sq ft figure uses 2 ACH, while the 250 uses 4 ACH for its 465 sq ft figure. On named CADR, the 400S is higher but not three times higher: 328 versus 249 CFM for smoke. Compare the same air-change rate and the same particle type.
Review due. Check the current source before buying.
Does the Blue Pure 211i Max purifier-only package include a filter subscription?
No. The reviewed Air Purifier Only selection is a one-time purchase that includes one Particle & Carbon filter and one Stockholm Fog fabric prefilter. Filter subscriptions and specialty filters are separate selections.
Review due. Check the current source before buying.
Evidence limits
These manufacturer specifications do not establish measured performance, noise, long-term reliability or running cost. We have not independently tested these products. Check current prices, stock and operating-space instructions with the seller and manufacturer.
Includes the standard prefilter and Max2 configuration; no spare-filter bundle.
Source · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier OnlyBlue Pure 211i Max; Air Purifier Only; one-time purchase.
The link may open several packages. Check current price and availability with the seller. Opens in a new tab.
External rating
Coway Airmega 250 — standard US unit
4.7 out of 5from 79 ratings · Coway US store ↗ · Checked October 23, 2026.
Blueair Blue Pure 211i Max — Air Purifier Only
4.8 out of 5from 601 ratings · Best Buy ↗ · Checked October 23, 2026.
Airmega 400S — US standard package
4.1 out of 5from 45 ratings · Coway US store ↗ · Checked October 23, 2026.
Smoke CADR
Clean-air delivery rate specifically identified for smoke particles.
Compare like-for-like particle ratings; this is not a gas-removal or health-outcome rating.
Coway Airmega 250 — standard US unit249 cfmSources · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.Coway: Air-filter ratings and CADR unitsChecked 2026-09-30. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier Only435 cfmSource · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Review due. Check the current source before buying.
Dust CADR
Clean-air delivery rate specifically identified for dust.
Keep this separate from smoke and pollen CADR.
Coway Airmega 250 — standard US unit261 cfmSources · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.Coway: Air-filter ratings and CADR unitsChecked 2026-09-30. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier Only452 cfmSource · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Review due. Check the current source before buying.
Pollen CADR
Clean-air delivery rate specifically identified for pollen.
Use the same particle type when comparing models.
Coway Airmega 250 — standard US unit230 cfmSources · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.Coway: Air-filter ratings and CADR unitsChecked 2026-09-30. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier Only450 cfmSource · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Review due. Check the current source before buying.
CADR without a named particle type
A maker-listed CADR whose particle type is not specified by the cited source.
This value is not substituted for a smoke, dust or pollen rating.
Coway Airmega 250 — standard US unitNot verified
We have not verified this value. It is not a confirmed no or zero. Check the original source or ask the manufacturer if it affects your choice.
The source supplies separate smoke, dust and pollen ratings.Source · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier OnlyNot verified
We have not verified this value. It is not a confirmed no or zero. Check the original source or ask the manufacturer if it affects your choice.
The source supplies separate particle ratings.Source · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Airmega 400S — US standard packageNot verified
We have not verified this value. It is not a confirmed no or zero. Check the original source or ask the manufacturer if it affects your choice.
The cited specifications provide separate particle ratings and no additional unnamed CADR.Source · 2026-09-13Coway: Airmega 400S — US product and specificationsChecked 2026-09-13. Read the original source and its check date before relying on this value.
Review due. Check the current source before buying.
Advertised room area
The documented room area at the air-change assumption below.
Area claims at different ACH are not directly equivalent; check ceiling height and layout.
Coway Airmega 250 — standard US unit465 sq ftManufacturer sizing assumes an eight-foot ceiling and maximum fan speed.Sources · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.Coway: CADR and room-sizing explanationChecked 2026-09-30. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier Only674 sq ftRead with the stated 4.8 ACH assumption.Source · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Airmega 400S — US standard package1560 sq ftPaired with 2 ACH; the manual specifies an 8 ft ceiling.Sources · 2026-09-13Coway: Airmega 400S — US product and specificationsChecked 2026-09-13. Read the original source and its check date before relying on this value.Coway: Airmega 300, 400 and S-series US manualChecked 2026-09-13. Read the original source and its check date before relying on this value.
Review due. Check the current source before buying.
Room-area air changes
Air changes per hour used for the displayed room-area claim.
Read this together with room area. Actual airflow depends on placement and operating setting.
Coway Airmega 250 — standard US unit4 ACHSource · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier Only4.8 ACHSource · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Airmega 400S — US standard package2 ACHApplies to 1,560 sq ft. The manual also gives 780 sq ft at 4 ACH.Sources · 2026-09-13Coway: Airmega 400S — US product and specificationsChecked 2026-09-13. Read the original source and its check date before relying on this value.Coway: Airmega 300, 400 and S-series US manualChecked 2026-09-13. Read the original source and its check date before relying on this value.
Review due. Check the current source before buying.
Rated power
The documented rated or maximum electrical input, as qualified by the source.
Actual energy use depends on the fan setting. Read the source conditions alongside the value.
Coway Airmega 250 — standard US unit64 WManufacturer power-consumption specification.Source · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier Only46 WListed as energy consumption; not a measured all-settings average.Source · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Review due. Check the current source before buying.
App control
Whether the listed model supports control through the manufacturer’s app.
Check phone requirements, network setup and which controls remain available on the unit.
Coway Airmega 250 — standard US unitNot verified
We have not verified this value. It is not a confirmed no or zero. Check the original source or ask the manufacturer if it affects your choice.
App control is not established for this exact model by the cited page.Source · 2026-09-12Coway: Airmega 250 US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier OnlyYesSource · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Airmega 400S — US standard packageYesThe S model supports Wi-Fi and mobile app control.Source · 2026-09-13Coway: Airmega 400S — US product and specificationsChecked 2026-09-13. Read the original source and its check date before relying on this value.
Review due. Check the current source before buying.
Standard replacement filter
The named replacement for the standard included filter where verified.
Match the exact purifier model and distinguish standard filters from optional specialty versions.
Coway Airmega 250 — standard US unitAirmega 250 Max2 filter (3109144)Source · 2026-09-12Coway: Airmega 250 Max2 filterChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Blueair Blue Pure 211i Max — Air Purifier OnlyBlue Pure 211i Max Particle & Carbon filterThe standard option differs from Allergenblock and Smokeblock filters.Source · 2026-09-12Blueair: Blue Pure 211i Max US product pageChecked 2026-09-12. We reviewed the official page text on the check date. Checkout options were not verified.
Review due. Check the current source before buying.
Airmega 400S — US standard packageAirmega 400 / 400S Max2 Filter Set, SKU 3104756 — two filtersOne Max2 filter fits each side; the washable pre-filters are separate components.Source · 2026-09-13Coway: Airmega 400 and 400S Max2 Filter SetChecked 2026-09-13. Read the original source and its check date before relying on this value.
Review due. Check the current source before buying.
Questions to check before buying
Coway Airmega 250 — standard US unit
This is Airmega 250, not the 250S or 250 Art. App features from those names are not assumed.
Blueair Blue Pure 211i Max — Air Purifier Only
The purifier-only package is separate from the recurring filter-subscription option.
Airmega 400S — US standard package
The 1,560 sq ft area assumes 2 ACH and an 8 ft ceiling; it is not a 4.8 ACH room rating.
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