Head to head
Coway Airmega 400 vs Blueair Blue Pure 311i Max
Coway Airmega 400 leads 4 to 1 on the 5 rankable specs, but Blueair Blue Pure 311i Max costs $320 less.
Catalog as of September 1, 2026
Why, in numbers
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Levoit Core 300S Smart True HEPA Air Purifier$149Winix 5500-2 Air Purifier$159Levoit Core 400S$219Coway Airmega AP-1512HH Mighty$229Honeywell HPA300 HEPA Air Purifier$249Levoit Core 600S Smart True HEPA$299Blueair Blue Pure 211+ Auto$339Coway Airmega 250$399Blueair Protect 7470i$649Alen BreatheSmart 75i Large Room Air Purifier$749Dyson Purifier Hot+Cool Formaldehyde HP09$799Buying for
Straight answer
Overall: 4 to 1
Buy the Coway Airmega 400.
- Leads 4 of 5 rankable overall specs; Blueair Blue Pure 311i Max takes 1.
- CADR: 350 CFM vs 250 CFM
- Coverage area: 1,560 sq ft vs 387 sq ft
- Blueair Blue Pure 311i Max is $320 cheaper. Pay the difference only if cadr matters to you.
At a glance
The handful of numbers that decide most purchases in this category.
CADR
Coway
350 CFM (Smoke), 328 CFM (Dust), 400 CFM (Pollen)
Blueair
250 CFM (Smoke), 250 CFM (Dust), 250 CFM (Pollen)
Coverage area
Coway
1,560 sq ft (2 air changes/hr) / 780 sq ft (4 air changes/hr)
Blueair
387 sq ft (4.8 air changes/hr) / 929 sq ft (2 air changes/hr)
True 3-Year Cost of Ownership (TCO)
Coway Airmega 400
Blueair Blue Pure 311i Max
Room Placement & Bedroom Noise Check
Physical clearance required for airflow, wall placement, and bedroom noise levels.
Wall Clearance Required
Requires 12 in perimeter airflow space
360° fabric pre-filter intake (needs 12 in wall space)
Nighttime Sleep Mode Noise
Standard sleep speed
23 dB lowest speed setting
Unit Footprint & Dimensions
Standard room purifier footprint
Cylindrical aesthetic (12.4 × 12.4 × 18.9 in; 7.8 lb)
The 90-Day Owner Regret Check
Documented ergonomic quirks, hardware annoyances, and maintenance realities reported by real owners.
Coway: What to watch for
- Maintenance
Requires periodic filter replacements to maintain airflow and odor capture.
Blueair: What to watch for
- Maintenance
Outer fabric pre-filter attracts visible pet fur and lint.
Performance
leads 2-0| CADR | 350 CFM (Smoke), 328 CFM (Dust), 400 CFM (Pollen) (wins this row: higher) | 250 CFM (Smoke), 250 CFM (Dust), 250 CFM (Pollen) |
|---|---|---|
| Room size | Large living rooms, open floor plans, offices | Medium to large bedrooms, living rooms, and open offices up to 387 sq ft (4.8 ACH) / 929 sq ft (2 ACH) |
| Coverage area | 1,560 sq ft (2 air changes/hr) / 780 sq ft (4 air changes/hr) (wins this row: higher) | 387 sq ft (4.8 air changes/hr) / 929 sq ft (2 air changes/hr) |
Filters
2 differences| Filter types | Washable Pre-filter + Max2 Filter (True HEPA + Activated Carbon) | HEPASilent Main Particle + Carbon filter with customizable machine-washable fabric pre-filter |
|---|---|---|
| Filter life | 12 months (Max2 filter) / Washable pre-filters | 6 to 9 months (tracked by RealTrack algorithm in app) |
Usability & Smart
leads 1-0| Noise levels | 22 dB (Sleep mode) – 52 dB (Max speed) (wins this row: lower) | 23 dB (Night mode) – 50 dB (Max boost) |
|---|---|---|
| Energy consumption | 66 W max power consumption (Energy Star Certified) | 38 W max power consumption (Energy Star Most Efficient) |
| Smart features | Smart Auto Mode + Eco Mode (no Wi-Fi app) | Blueair App (iOS/Android), voice control with Amazon Alexa and Google Assistant, geofencing Welcome Home feature |
| Air quality sensors | Real-time particle sensor with colorful LED ring indicator | Laser particle sensor with 5-color LED air quality indicator ring (PM1, PM2.5, PM10) |
Design & Ownership
2 differences| Weight | 24.7 lb (11.2 kg) | 7.8 lb (3.5 kg) (wins this row: lower) |
|---|---|---|
| Warranty | 5 years limited motor / 1 year electronic parts (wins this row: higher) | 2 years limited warranty (extendable to 3 years with product registration) |
Which one should you buy
Pick this one if
Coway Airmega 400
Dual-suction large room air purifier with Max2 HEPA and activated carbon filtration covering 1,560 sq ft.
- Massive CADR cleans up to 1,560 sq ft twice per hour
- Dual-sided air intake with combined True HEPA and carbon filters
- Smart Eco mode turns off fan when air remains clean for 30 minutes
What you give up
- Cube design has a large floor footprint
- No mobile app connectivity on the non-S model
Pick this one if
Blueair Blue Pure 311i Max
Smart air purifier with HEPASilent dual filtration technology, cleaning up to 929 sq ft in 30 minutes, 23dB whisper quiet operation, and Blueair app control.
- HEPASilent dual filtration combines electrostatic and mechanical filtration for faster airflow at lower noise
- Cleans up to 387 sq ft in 12.5 minutes (4.8 ACH) / up to 929 sq ft in 30 minutes (2 ACH)
- Ultra-quiet 23dB Night Mode with Energy Star certified low electricity draw
What you give up
- Fabric pre-filter covers the exterior and requires periodic vacuuming/washing
- Filter replacements needed every 6 to 9 months
Best for each use
Bedrooms
Tied on bedrooms. Blueair Blue Pure 311i Max is cheaper.
Big rooms & allergies
For big rooms & allergies, buy the Coway Airmega 400.
Low running cost
Too close to call on low running cost from the spec sheets. Only warranty is rankable here.
Done deciding?
Open the full standalone spec sheet for either device.
Manufacturer pages: Coway Airmega 400 ↗ · Blueair Blue Pure 311i Max ↗
Common questions
Which is cheaper, the Coway Airmega 400 or the Blueair Blue Pure 311i Max?
Blueair Blue Pure 311i Max costs $320 less at list price.
What is the biggest catch with the Coway Airmega 400 or Blueair Blue Pure 311i Max?
Coway Airmega 400 has this deal-breaker: no Wi-Fi app. No schedules or remote control from your phone.
Which is better for bedrooms, the Coway Airmega 400 or the Blueair Blue Pure 311i Max?
Tied on bedrooms. Blueair Blue Pure 311i Max is cheaper. The 2 rankable bedrooms specs split 1 to 1. Saves $320 at list price.
What cannot be compared from spec sheets?
Of the 11 specs tracked here, 6 are descriptive and cannot be ranked on numbers alone. Spec sheets also cannot measure subjective factors like build quality, real-world performance, or comfort.