Head-to-Head Comparison
Coway Airmega 400 vs Blueair Blue Pure 311i Auto: Large Room vs Bedroom Air Purifier
The Coway Airmega 400 dominates large spaces with 1560 sq ft coverage and the highest CADR ratings, while the Blueair Blue Pure 311i Auto excels in bedrooms with whisper-quiet 17 dB operation and AAFA allergy certification. Choose based on room size and whether quiet sleep matters most.
Winner
Coway
Airmega 400
8.9
$549VS
Blueair
Blue Pure 311i Auto
8.8
$299R3 Research Verdict
The Coway Airmega 400 dominates large spaces with 1560 sq ft coverage and the highest CADR ratings, while the Blueair Blue Pure 311i Auto excels in bedrooms with whisper-quiet 17 dB operation and AAFA allergy certification. Choose based on room size and whether quiet sleep matters most.
Updated Jan 29, 20269 attributes comparedBy R3 Research Team
Different Tools for Different Rooms
Research-backed recommendation
This comparison is less about which is better and more about which is right for your specific need.
Choose the Coway Airmega 400 if: You have a large open-plan living area, great room, or combined living/dining/kitchen space. The 1560 sq ft coverage and 450 CFM smoke CADR make it the clear choice for whole-room protection, especially during wildfire season. The 5-year warranty protects your investment.
Choose the Blueair Blue Pure 311i Auto if: Your priority is a bedroom, nursery, or any space where quiet operation matters. The 17 dB sleep mode is genuinely inaudible, and the AAFA allergy certification means proven allergen reduction for families managing allergies or asthma.
Consider both if: You have a large home and want comprehensive coverage - the Airmega 400 for main living areas, Blueair 311i Auto for bedrooms.
Pros & Cons at a Glance
Quick summary of each product's strengths and weaknesses
Coway
Airmega 400
Winner
Pros
- Better Coverage Area
- Better CADR Smoke
- Better Warranty
- Better Filter Life
Cons
- Loses on Noise (Low)
- Loses on Allergy Certification
- Loses on Price
Blueair
Blue Pure 311i Auto
Pros
- Better Noise (Low)
- Better Allergy Certification
- Better Price
- Better Portability
Cons
- Loses on Coverage Area
- Loses on CADR Smoke
- Loses on Warranty
Who Wins Each Category?
A quick breakdown of how these products compare head-to-head
Coverage Area
Coway
Win
Airmega covers 3x the space - ideal for open floor plans
Cadr Smoke
Coway
Win
Nearly double the smoke filtration capacity
Noise (low)
Blueair
Win
Blueair is nearly inaudible - critical for bedrooms
Allergy Certification
Blueair
Win
Blueair has proven allergen reduction certification
Price
Blueair
Win
Blueair is nearly half the cost
Warranty
Coway
Win
Airmega has industry-leading warranty coverage
Filter Life
Coway
Win
Airmega requires half as many filter changes
Wildfire Smoke
Coway
Win
Higher CADR and larger carbon layer handles heavy smoke better
Portability
Blueair
Win
Blueair easily moves between rooms
Winner
Tie
Which One Is Right For You?
Personalized recommendations based on your priorities
Buy Coway If You...Winner
- Large open-plan living spaces over 500 sq ft
- Homes in wildfire-prone areas needing maximum smoke filtration
- Families wanting long-term investment with 5-year warranty
- Anyone who prefers fewer filter changes
Buy Blueair If You...
- Bedrooms and nurseries where whisper-quiet operation is essential
- Families with allergies or asthma seeking certified allergen reduction
- Medium rooms under 500 sq ft
- Budget-conscious buyers with moderate space needs
- Those who need portable units to move between rooms
Head-to-Head Comparison
Detailed attribute-by-attribute breakdown
Coway
vs5
Blueair
4
| Attribute | Coway | Blueair | Winner |
|---|---|---|---|
| Coverage Area Airmega covers 3x the space - ideal for open floor plans | 1560 sq ft | 500 sq ft | Coway |
| CADR Smoke Nearly double the smoke filtration capacity | 450 CFM | 250 CFM | Coway |
| Noise (Low) Blueair is nearly inaudible - critical for bedrooms | 24 dB | 17 dB | Blueair |
| Allergy Certification Blueair has proven allergen reduction certification | None | AAFA Certified | Blueair |
| Price Blueair is nearly half the cost | $549 | $299 | Blueair |
| Warranty Airmega has industry-leading warranty coverage | 5 years | 2 years | Coway |
| Filter Life Airmega requires half as many filter changes | 12 months | 6 months | Coway |
| Wildfire Smoke Higher CADR and larger carbon layer handles heavy smoke better | Excellent | Good | Coway |
| Portability Blueair easily moves between rooms | 22 lbs | 6.4 lbs | Blueair |
Coway
5 Wins
Blueair
4 Wins
Coverage Area
Coway
1560 sq ft
500 sq ft
Airmega covers 3x the space - ideal for open floor plans
CADR Smoke
Coway
450 CFM
250 CFM
Nearly double the smoke filtration capacity
Noise (Low)
Blueair
24 dB
17 dB
Blueair is nearly inaudible - critical for bedrooms
Allergy Certification
Blueair
None
AAFA Certified
Blueair has proven allergen reduction certification
Price
Blueair
$549
$299
Blueair is nearly half the cost
Warranty
Coway
5 years
2 years
Airmega has industry-leading warranty coverage
Filter Life
Coway
12 months
6 months
Airmega requires half as many filter changes
Wildfire Smoke
Coway
Excellent
Good
Higher CADR and larger carbon layer handles heavy smoke better
Portability
Blueair
22 lbs
6.4 lbs
Blueair easily moves between rooms
$Price Analysis
The Airmega 400 costs $250 more upfront ($549 vs $299) but covers 3x the space and has half the annual filter cost. For a single bedroom, the Blueair is more cost-effective. For large spaces, the Airmega's cost-per-square-foot is actually competitive.
Best Time to Buy
Buy the Airmega 400 if you need whole-room coverage for a living area or great room. Buy the Blueair 311i Auto if bedroom quiet operation and allergy certification are priorities. Consider one of each for comprehensive home coverage.
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Independent Research
No sponsored placements. Data-driven verdicts.
1,000+ data points
Updated January 29, 2026
R
R3 Research Team
•Evidence-Based Review BoardOur multidisciplinary team of researchers, parents, and medical advisors dedicated to finding the safest products for your family.
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