The catch
Coway Airmega 300
Since the two Max2 filters are replaced together, compare what the full set costs.
Side by side
Coway Airmega 300 vs Coway Airmega 400: 400 leaves more margin on room size, 300 saves floor space if its airflow is enough
Quick verdict
The Airmega 400 is the pick for more room-size margin. When your room is already covered by the lower airflow of the Airmega 300, that model saves floor space and weight.
Before you buy
Why, and what it costs you
Compare room sizes at an equal turnover rate
At five air changes per hour and an eight-foot ceiling, the calculation gives about 428 square feet for Coway Airmega 300 and 492 for Coway Airmega 400.
Where this comes from
Area = CADR × 60 / (ceiling feet × air changes per hour). Inputs are 285 and 328 CFM, 8 feet and 5 changes. Smoke CADR is the figure used, at maximum speed. Real conditions are influenced by air mixing, furniture, open doors and filter loading.
The catch
Coway Airmega 400
You won't get a Wi-Fi app, scheduling or a detailed air-quality history.
Coway Airmega 300
- Why pick it
- Placement is simpler with a smaller square cabinet
- The unit moves from room to room
- The catch
- Since the two Max2 filters are replaced together, compare what the full set costs.
Coway Airmega 400
- Why pick it
- The living room needs more airflow
- It will sit in a fixed spot
- The catch
- You won't get a Wi-Fi app, scheduling or a detailed air-quality history.
The Airmega 400 photo shows Graphite, while the Amazon listing selects White. Its purchase link is paused while the exact finish is verified.
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What this page compares
More room-size margin points to the Airmega 400. The Airmega 300 saves floor space and weight when its lower airflow already covers your room.
The step up gives a helpful but limited margin
Which one fits
Pick the situations that sound like you
The room is big enough to call for extra airflow
With the same five-change target and eight-foot ceiling, the calculated limits are 428 square feet for Coway Airmega 300 and 492 for Coway Airmega 400. Leave margin if you want to run below maximum speed.
- Coway Airmega 300
- Depends
- Coway Airmega 400
- Better fit
The cabinet needs to fit next to furniture
Coway Airmega 300 needs 13.6 inches of width and 13.6 inches of depth, and Coway Airmega 400 needs 14.8 by 14.8. Intake clearance comes on top, so measure the gap in both directions.
- Coway Airmega 300
- Depends
- Coway Airmega 400
- Depends
I want to run it from another room
Coway Airmega 300 and Coway Airmega 400 both lack app control. If remote schedules are essential, choose a connected alternative.
- Coway Airmega 300
- Not suitable
- Coway Airmega 400
- Not suitable
Ceiling height is ten feet
Take the ceiling up to ten feet with five air changes and the modeled room areas drop to 342 square feet for Coway Airmega 300 and 394 for Coway Airmega 400. That is 20% less floor area than the eight-foot example, because the purifier has more air to move.
- Coway Airmega 300
- Depends
- Coway Airmega 400
- Depends
In practice
Differences you will notice
Compare room sizes at an equal turnover rate
At five air changes per hour and an eight-foot ceiling, the calculation gives about 428 square feet for Coway Airmega 300 and 492 for Coway Airmega 400.
How we worked this out
Area = CADR × 60 / (ceiling feet × air changes per hour). Inputs are 285 and 328 CFM, 8 feet and 5 changes. Smoke CADR is the figure used, at maximum speed. Real conditions are influenced by air mixing, furniture, open doors and filter loading.
Measure the cabinet first, then buy
Coway Airmega 300 has a 185-square-inch cabinet envelope, against 219 for Coway Airmega 400. A shallower shape may still need more wall width.
How we worked this out
Width × depth: 13.6 × 13.6 = 185 in² and 14.8 × 14.8 = 219 in². These measure the cabinet bounding rectangles, so required air clearance is not part of them.
The 300 has the smaller footprint
Compared with the 400, the Airmega 300 takes up about 16% less rectangular floor area and is 3.3 pounds lighter.
How we worked this out
1 - (13.6 × 13.6) / (14.8 × 14.8) = 15.6%. 24.7 - 21.4 = 3.3 lb. Both units need extra space around their intakes.
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 300
Works with your numbers285 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.
Coway Airmega 400
Works with your numbers328 CFM of verified clean-air delivery works out to about 8.2 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-1515H
Airmega 300
This two-sided living-room purifier has washable prefilters and automatic fan control, and it needs no app setup.
- Best for
- A shared room where controls on the unit and washable intake screens will do
Facts we checked
- CADR is 285 CFM for smoke, 306 for dust and 339 for pollen.
- The cabinet is 13.6 by 13.6 by 21.2 inches and weighs 21.4 lb.
- Power is rated at 57 watts. Auto and Eco modes run without Wi-Fi.
Option B
Coway, AP-2015F
Airmega 400
Wide and high in airflow, this purifier has dual filters, two washable prefilters and straightforward automatic controls, with no app involved.
- Best for
- Large rooms with smoke or allergy problems, if you value a mechanical HEPA system over connected features
Facts we checked
- Coway's rating for the platform is up to 3,120 square feet at one air change per hour.
- Published CADR is 328 CFM for smoke, 328 for dust and 400 for pollen.
- Two combined Max2 HEPA-and-carbon filters sit behind two washable prefilters.
The Airmega 400 photo shows Graphite, while the Amazon listing selects White. Its purchase link is paused while the exact finish is verified.
Spec by spec
Where they really differ
| Spec | Coway Airmega 300 | Coway Airmega 400 | In practice |
|---|---|---|---|
| Smoke CADR | 285 CFM | 328 CFM | Better to rely on a smoke-specific rate than on a one-air-change marketing room size. |
| Pollen CADR | 339 CFM | 400 CFM | The model that leads on smoke does not necessarily lead on pollen as well. |
| Cabinet width and depth | 13.6 × 13.6 in | 14.8 × 14.8 in | Check both dimensions against the real gap, and keep the clearance the manual calls for around the intakes. |
| Remote app control | No app | No app | Remote schedules matter if the purifier sits far from where you spend your day. |
| Automatic sensor response | Included | Included | Apps and pollution sensors do separate jobs, and a schedule tells you nothing about air quality. |
| Ionizer or electrostatic stage | none | none | If a purely mechanical filter path is what you want, treat this preference as a firm requirement. |
| Published weight | 21.4 lb | 24.7 lb | A heavy cabinet bothers you less if it stays put than if it must go upstairs every day. |
| Rated power | 57 W | 66 W | Rated input is a comparison of upper limits. Actual consumption shifts with Auto mode and lower fan settings. |
Trade-offs
What each pick costs you
With Coway Airmega 300
- The 2,512-square-foot headline refers to one air change per hour. Our smoke sizing example at five changes comes to about 428 square feet.
With Coway Airmega 400
- The wide body takes up a lot of floor space and needs room to breathe on both intake sides.
Decision guide
How to decide
Go with the Airmega 400 for extra room-size margin. If the Airmega 300's lower airflow already covers your room, it saves floor space and weight.
The step up gives a helpful but limited margin
Going from 285 to 328 in smoke CADR adds about 65 square feet at five changes and an eight-foot ceiling. That helps near the smaller model's limit and is not a whole extra room.
Leave space on both sides regardless
Side intakes and paired filters are used on both Airmegas. Check the cabinet dimensions and keep the intake space the manual specifies, particularly next to a sofa.
Don't assume the filters are compatible
Different Max2 filter sets go into the 300 and the 400. Spares for either model won't fit the other, even though both take two filters.
What this page can’t tell you
- CADR is based on the maximum rated fan speed, and minimum noise and maximum airflow occur at different operating points.
- What these calculations compare is particle-cleaning capacity. Nothing in them promises health outcomes or the removal of a specific gas.
By the numbers
What the data shows
What we found across the air purifiers we compare, plus the checked facts behind each finding.
How many fit
Only 14 of the 70 models checked meet every need here: “Wildfire smoke makes its way inside”, “Floor space is very tight for me”, and “I want it to respond automatically”.
14 models fit, out of 70 checkedThe gap in numbers
Coway Airmega 400 lists 328 CFM for listed smoke CADR, 15% more than the 285 CFM on Coway Airmega 300.
- Coway Airmega 300
- 285 CFM
- Coway Airmega 400
- 328 CFM
- Models with this figure
- 20 of 70
Show the facts and the math
How we countedThe count uses each product's current fit ratings for “Wildfire smoke makes its way inside”, “Floor space is very tight for me”, and “I want it to respond automatically”. A need with no documented match is not counted.
How we calculatedOnly figures stated as smoke CADR go into this median. General maximum-airflow numbers are left out. For context, 20 of 70 models publish comparable figures.
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| Coway Airmega 300 |
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| Coway Airmega 400 |
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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 300
Placement is simpler with a smaller square cabinet
See price & reviews on AmazonCoway Airmega 400
The living room needs more airflow
The Airmega 400 photo shows Graphite, while the Amazon listing selects White. Its purchase link is paused while the exact finish is verified.
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