The catch
Coway Airmega Mighty
With its lower smoke CADR, it can come up short in a room that Blueair handles under the same maximum-output assumptions. Eco is designed to allow fan stops.
Side by side
Coway Mighty vs Blueair 311i Max: Coway takes less depth, Blueair takes less width, and Eco may stop the fan
Quick verdict
Blue Pure 311i Max suits you if width or rated particle-cleaning headroom is the priority. Coway Mighty suits you if front-to-back depth is tighter and local controls cover your routine. The cabinet base areas turn out to be surprisingly close despite the different shapes. Coway Eco can stop the fan after 30 minutes without detected pollution, so pick a suitable manual setting if you plan on uninterrupted circulation. Neither quietest mode is verified to deliver its maximum CADR.
Before you buy
Why, and what it costs you
Footprints that are almost equal can still bring very different placement problems
Blueair seems compact because it is 4.3 inches narrower than Coway, but it is also 2.9 inches deeper. Multiply width by depth and the enclosing rectangles are only about 3% apart. Next to a sofa, Coway’s shallow body can leave more walkway even though its rectangle is slightly larger. Between two pieces of furniture, Blueair’s narrower width may serve you better. Neither should be wedged into a gap where air can't get through. Coway’s manual asks for at least 20 cm from nearby walls and objects, so cabinet dimensions are only the first check.
Where this comes from
16.8 × 9.6 comes to 161.28 in² and 12.5 × 12.5 to 156.25 in². The relative reduction is 3.12%. Widths differ by 4.3 inches and depths by 2.9. Those are enclosing rectangles. They do not show the area the cabinets touch. Clearances come on top.
The catch
Blueair Blue Pure 311i Max
The narrow shape is 2.9 inches deeper. A washable fabric cover doesn't change the fact that you still buy replacement particle/carbon filters.
Coway Airmega Mighty
- Why pick it
- Your room calls for a shallower cabinet, and you have space for Coway’s 16.8-inch width plus clearance.
- Fan and timer controls on the unit itself are what you want. If you need continuous circulation, set a suitable manual speed rather than Eco.
- The catch
- With its lower smoke CADR, it can come up short in a room that Blueair handles under the same maximum-output assumptions. Eco is designed to allow fan stops.
Blueair Blue Pure 311i Max
- Why pick it
- The 12.5-inch cabinet width suits your room better, and you can spare the extra depth while keeping airflow clear.
- Higher rated particle delivery or app scheduling is what you need. Even so, the published maximum does not describe Night mode.
- The catch
- The narrow shape is 2.9 inches deeper. A washable fabric cover doesn't change the fact that you still buy replacement particle/carbon filters.
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What this page compares
Picking between Coway Mighty and Blueair 311i Max for a bedroom or living room? Weigh width against depth, smoke room sizing and the fan behavior that sits behind the automatic convenience.
These popular household purifiers are aimed at the same realistic medium-room buyer. Both have particle-aware automatic control and washable coarse prefilters. What separates them is geometry, maximum delivery and how the owner handles fan behavior.
Which one fits
Pick the situations that sound like you
A shallow body counts for more than a narrow one
Coway's body is 2.9 inches shallower, though clearance is still required.
- Coway Airmega Mighty
- Better fit
- Blueair Blue Pure 311i Max
- Good
The tight dimension is cabinet width
Before operating clearance, Blueair is 4.3 inches narrower.
- Coway Airmega Mighty
- Good
- Blueair Blue Pure 311i Max
- Better fit
My plan is five smoke-equivalent changes in 400 sq ft at 8 ft high
Blueair passes the maximum-output calculation and Coway does not.
- Coway Airmega Mighty
- Caution
- Blueair Blue Pure 311i Max
- Better fit
I need to hit that same target under a 10 ft ceiling
In the bigger volume, both come up short.
- Coway Airmega Mighty
- Not suitable
- Blueair Blue Pure 311i Max
- Not suitable
I need cleaning delivery proven at a quiet overnight speed
That lower-speed result is not established by either maximum CADR.
- Coway Airmega Mighty
- Depends
- Blueair Blue Pure 311i Max
- Depends
In practice
Differences you will notice
Footprints that are almost equal can still bring very different placement problems
Blueair seems compact because it is 4.3 inches narrower than Coway, but it is also 2.9 inches deeper. Multiply width by depth and the enclosing rectangles are only about 3% apart. Next to a sofa, Coway’s shallow body can leave more walkway even though its rectangle is slightly larger. Between two pieces of furniture, Blueair’s narrower width may serve you better. Neither should be wedged into a gap where air can't get through. Coway’s manual asks for at least 20 cm from nearby walls and objects, so cabinet dimensions are only the first check.
How we worked this out
16.8 × 9.6 comes to 161.28 in² and 12.5 × 12.5 to 156.25 in². The relative reduction is 3.12%. Widths differ by 4.3 inches and depths by 2.9. Those are enclosing rectangles. They do not show the area the cabinets touch. Clearances come on top.
A high ceiling can cancel out the airflow upgrade
For 400 square feet under an 8-foot ceiling, the rated smoke figures translate to about 4.4 equivalent air changes per hour for Coway and 5.3 for Blueair. Blueair gets past our five-change planning line. If the ceiling is 10 feet instead, the numbers drop to about 3.5 and 4.2, and neither gets there. A room that looks the same but is taller may call for a different purchase. These figures come from rated maximum output, not the setting that sounds best at bedtime, and they don't predict symptom relief or complete pollutant removal.
How we worked this out
233 × 60 ÷ 3200 gives 4.369 ACH and 283 × 60 ÷ 3200 gives 5.306. At 4000 ft³ you get 3.495 and 4.245. Five ACH is a comparison assumption stated openly.
A hands-off mode can work against keeping air moving all night
Coway Eco is built to stop the fan after 30 minutes with no pollution detected. That helps when you want the fan to run less, but it clashes with a plan for continuous circulation, so pick a suitable manual speed instead. Blueair has app schedules and Night mode, but its maximum CADR can't be attributed to that low setting. A light sleeper who needs a specific overnight cleaning rate won't settle the purchase on a quietness headline or an automatic mode. What you need is verified delivery at a speed you can tolerate, and this comparison doesn't establish it.
How we worked this out
This sets Eco's documented fan-stop behavior and the limits of the maximum ratings against a continuous overnight plan. It makes up no sleep-speed CADR and gives no medical recommendation.
Plug in your numbers
Can either purifier keep up with your room?
This checks hard limits only. Personal preferences are left out of the math.
Coway Airmega Mighty
Works with your numbers233 CFM of verified clean-air delivery works out to about 5.8 air changes per hour in this room. Hitting the 5 ACH target takes 200 CFM.
Blueair Blue Pure 311i Max
Works with your numbers283 CFM of verified clean-air delivery works out to about 7.1 air changes per hour in this room. Hitting the 5 ACH target takes 200 CFM.
This uses each model’s pollutant-specific CADR at top speed and a target of five air changes per hour. Quieter settings clean less air. Raw airflow and one-change coverage claims are never swapped in.
Option A
Coway, AP-1512HH
Airmega Mighty
Your room calls for a shallower cabinet, and you have space for Coway’s 16.8-inch width plus clearance.
- Best for
- Your room calls for a shallower cabinet, and you have space for Coway’s 16.8-inch width plus clearance.
Facts we checked
- Width and depth: 16.8 × 9.6 inches
- Width × depth, before clearance: About 161 square inches
- Rated smoke CADR: 233 CFM
- Rated dust and pollen CADR: 246 dust and 240 pollen CFM
Option B
Blueair, 311i Max
Blue Pure 311i Max
The 12.5-inch cabinet width suits your room better, and you can spare the extra depth while keeping airflow clear.
- Best for
- The 12.5-inch cabinet width suits your room better, and you can spare the extra depth while keeping airflow clear.
Facts we checked
- Width and depth: 12.5 × 12.5 inches
- Width × depth, before clearance: About 156 square inches
- Rated smoke CADR: 283 CFM
- Rated dust and pollen CADR: 314 dust and 365 pollen CFM
Spec by spec
Where they really differ
| Spec | Coway Airmega Mighty | Blueair Blue Pure 311i Max | In practice |
|---|---|---|---|
| Width and depth | 16.8 × 9.6 inches | 12.5 × 12.5 inches | Blueair is narrower but deeper. The right shape depends on the room, and a generic compact label tells you little. |
| Width × depth, before clearance | About 161 square inches | About 156 square inches | These enclosing rectangles are only about 3% apart. That is not the contact area of the rounded cabinets. |
| Rated smoke CADR | 233 CFM | 283 CFM | Blueair has 50 CFM more rated smoke-particle delivery, which says nothing about odor or gas removal. |
| Rated dust and pollen CADR | 246 dust and 240 pollen CFM | 314 dust and 365 pollen CFM | Tie the pollutant rating to the calculation. The largest figure shouldn't stand in for every concern. |
| Automatic control | Dust sensor, Auto and separate Eco mode | PM2.5 sensing, Auto and app schedules | Coway Eco is able to stop the fan. Scheduling and automatic sensing are different choices. |
| Prefilter and main filter | Washable prefilter plus replaceable deodorization and HEPA | Washable fabric prefilter plus replaceable particle/carbon filter | Cleaning pet hair regularly and replacing the main filter are still different maintenance jobs. |
Trade-offs
What each pick costs you
With Coway Airmega Mighty
- The replacement deodorization filter and the HEPA filter each have their own expected interval. Before estimating running cost, check the exact pack and how you will use it.
With Blueair Blue Pure 311i Max
- Optional SmokeBlock or AllergenBlock claims don't carry over to the standard unit selected. Check which filter is included.
Change of plan
When the answer changes
Depth is what limits the cabinet in this room
Go with Coway Airmega Mighty. Coway has the shallower body, as long as its width and clearances fit too.
Width matters more, or the higher rated particle delivery does
Go with Blueair Blue Pure 311i Max. Blueair has the narrower body and the higher pollutant-specific CADRs.
Five smoke-equivalent changes are required in 400 sq ft at 10 ft high
Neither model fits. Even at rated maximum output, neither reaches that planning target.
Decision guide
Before you buy
The goal is enough cleaning headroom without the purifier becoming an obstacle. Blueair is much narrower and has the higher rated delivery, while Coway is shallower. One compactness label would hide that trade-off.
What this page can’t tell you
- This page supplies neither a matched noise test nor a quiet-speed CADR.
- Calculations for particle cleaning say nothing about gas removal, odor elimination or health benefits.
By the numbers
What the data shows
What we found across the air purifiers we compare, plus the checked facts behind each finding.
Show the facts and the math
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| Coway Airmega Mighty |
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| |
| Blueair Blue Pure 311i Max |
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Ready to buy
See today’s price and what owners say
Open either model on Amazon for the current price, customer reviews and delivery options.
Coway Airmega Mighty
Your room calls for a shallower cabinet, and you have space for Coway’s 16.8-inch width plus clearance.
Fan and timer controls on the unit itself are what you want. If you need continuous circulation, set a suitable manual speed rather than Eco.
See price & reviews on AmazonBlueair Blue Pure 311i Max
The 12.5-inch cabinet width suits your room better, and you can spare the extra depth while keeping airflow clear.
Higher rated particle delivery or app scheduling is what you need. Even so, the published maximum does not describe Night mode.
See price & reviews on AmazonEach link opens in a new tab.
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