Main trade-off
Coway Airmega 300
The two Max2 filters are replaced as a set, so compare the cost of the full set.
Head-to-head
Coway Airmega 300 vs Coway Airmega 400: 400 adds room margin, 300 saves floor space when its airflow suffices
The short answer
Choose the Airmega 400 for more room-size margin. The Airmega 300 saves floor space and weight when its lower airflow already covers your room.
Before you choose
The reasoning and the trade-offs
Compare room size at the same turnover
At five air changes per hour and an eight-foot ceiling, Coway Airmega 300 calculates to about 428 square feet and Coway Airmega 400 to 492.
What this is based on
Area = CADR × 60 / (ceiling feet × air changes per hour). Inputs are 285 and 328 CFM, 8 feet and 5 changes. Smoke CADR is used at maximum speed. Air mixing, furniture, open doors and filter loading affect real conditions.
Main trade-off
Coway Airmega 400
There is no Wi-Fi app, scheduling or detailed air-quality history.
Coway Airmega 300
- Choose it for
- A smaller square cabinet is easier to place
- You carry the unit between rooms
- Main trade-off
- The two Max2 filters are replaced as a set, so compare the cost of the full set.
Coway Airmega 400
- Choose it for
- You need more living-room airflow
- The unit will stay in a fixed position
- Main trade-off
- There is no Wi-Fi app, scheduling or 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.
About this comparison
Choose the Airmega 400 for more room-size margin. The Airmega 300 saves floor space and weight when its lower airflow already covers your room.
The upgrade adds a useful but limited margin
Winner by situation
Start with what you need it to do
The room is large enough to need extra airflow
At 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. Allow margin if you want to run below maximum speed.
- Coway Airmega 300
- Depends
- Coway Airmega 400
- Better fit
The cabinet has to fit beside furniture
Allow 13.6 inches of width and 13.6 inches of depth for Coway Airmega 300, or 14.8 by 14.8 for Coway Airmega 400. Intake clearance is extra, so measure the gap in both directions.
- Coway Airmega 300
- Depends
- Coway Airmega 400
- Depends
I want control from another room
Neither Coway Airmega 300 nor Coway Airmega 400 has app control. Choose a connected alternative if remote schedules are essential.
- Coway Airmega 300
- Not suitable
- Coway Airmega 400
- Not suitable
The ceiling is ten feet high
At ten feet and five air changes, the modeled room areas fall 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
What matters in practice
The differences that matter
Compare room size at the same turnover
At five air changes per hour and an eight-foot ceiling, Coway Airmega 300 calculates to about 428 square feet and Coway Airmega 400 to 492.
How we reached this conclusion
Area = CADR × 60 / (ceiling feet × air changes per hour). Inputs are 285 and 328 CFM, 8 feet and 5 changes. Smoke CADR is used at maximum speed. Air mixing, furniture, open doors and filter loading affect real conditions.
Measure the cabinet before buying
Coway Airmega 300 occupies a 185-square-inch cabinet envelope versus 219 for Coway Airmega 400. A shallower shape can still need more wall width.
How we reached this conclusion
Width × depth: 13.6 × 13.6 = 185 in² and 14.8 × 14.8 = 219 in². These are cabinet bounding rectangles, excluding required air clearance.
A smaller footprint for the 300
The Airmega 300 uses about 16% less rectangular floor area and weighs 3.3 pounds less than the 400.
How we reached this conclusion
1 - (13.6 × 13.6) / (14.8 × 14.8) = 15.6%. 24.7 - 21.4 = 3.3 lb. Both require extra space around their intakes.
Try your real numbers
Will either purifier move enough clean air?
The result checks hard limits only. Preferences stay out of the calculation.
Coway Airmega 300
Fits these inputs285 CFM of verified clean-air delivery gives about 7.1 air changes per hour here. The 5 ACH target needs 200 CFM.
Coway Airmega 400
Fits these inputs328 CFM of verified clean-air delivery gives about 8.2 air changes per hour here. The 5 ACH target needs 200 CFM.
This uses maximum-speed, pollutant-specific CADR and a five-air-changes-per-hour target. Quieter settings deliver less clean air. It does not substitute raw airflow or a one-change coverage claim.
Choice A
Coway, AP-1515H
Airmega 300
A two-sided purifier for a living room with washable prefilters, automatic fan control and no app setup.
- Best matched use
- A shared room where local controls and washable intake screens are enough
Checked facts
- CADR is 285 smoke, 306 dust and 339 pollen CFM.
- The cabinet measures 13.6 by 13.6 by 21.2 inches and weighs 21.4 lb.
- Rated power is 57 watts. Auto and Eco modes work without Wi-Fi.
Choice B
Coway, AP-2015F
Airmega 400
A wide, high-airflow purifier with dual filters, two washable prefilters and simple automatic controls without an app.
- Best matched use
- Large rooms, smoke and allergy control when a mechanical HEPA system matters more than connected features
Checked facts
- Coway rates the platform for up to 3,120 square feet at one air change per hour.
- Its published CADR is 328 smoke, 328 dust and 400 pollen CFM.
- Two washable prefilters protect two combined Max2 HEPA-and-carbon filters.
The Airmega 400 photo shows Graphite, while the Amazon listing selects White. Its purchase link is paused while the exact finish is verified.
Meaningful differences
What changes the fit
| What changes | Coway Airmega 300 | Coway Airmega 400 | Why it matters |
|---|---|---|---|
| Smoke CADR | 285 CFM | 328 CFM | A smoke-specific rate is more useful than a one-air-change marketing room size. |
| Pollen CADR | 339 CFM | 400 CFM | The model with the higher smoke figure does not always have the higher pollen figure. |
| Cabinet width and depth | 13.6 × 13.6 in | 14.8 × 14.8 in | Match both dimensions to the actual gap and leave the manual clearance around the intakes. |
| Remote app control | No app | No app | Remote schedules matter when the purifier sits away from where you spend the day. |
| Automatic sensor response | Included | Included | An app and a pollution sensor perform different jobs. Schedules do not measure air quality. |
| Ionizer or electrostatic stage | none | none | Use this preference as a hard constraint if you want a purely mechanical filter path. |
| Published weight | 21.4 lb | 24.7 lb | A fixed location makes a heavy cabinet less troublesome than a daily move upstairs. |
| Rated power | 57 W | 66 W | Rated input is a ceiling comparison. Auto mode and lower fan settings change actual consumption. |
What you give up
Every choice has a cost
If you choose Coway Airmega 300
- Its 2,512-square-foot headline refers to one air change per hour. Our five-change smoke sizing example is about 428 square feet.
If you choose Coway Airmega 400
- Its broad body needs substantial floor space and clearance on both intake sides.
What matters in practice
How to make the call
The upgrade adds a useful but limited margin
Smoke CADR grows from 285 to 328, adding about 65 square feet at five changes and an eight-foot ceiling. That is useful near the smaller model's limit, rather than a whole extra room.
Both sides still need breathing room
Both Airmegas use side intakes and paired filters. Fit the cabinet dimensions and leave the intake space specified in the manual, especially beside a sofa.
Keep filter compatibility separate
The 300 and 400 use different Max2 filter sets. Owning one does not make its spare filters suitable for the other, even though both take two filters.
What this comparison cannot tell you
- CADR uses the maximum rated fan speed. Minimum noise and maximum airflow are different operating points.
- These calculations compare particle-cleaning capacity. They do not promise health outcomes or removal of a specific gas.
What the facts say
What the comparison shows
Useful conclusions from the current air purifiers comparison, followed by the checked facts used to reach them.
Compared set
Only 14 of 70 models checked match every need here: “Wildfire smoke gets indoors”, “I have very little floor space”, and “I want it to react on its own”.
14 matching models from 70 checkedMeasured difference
Coway Airmega 400 lists 328 CFM for published smoke CADR, 15% above Coway Airmega 300 at 285 CFM.
- Coway Airmega 300
- 285 CFM
- Coway Airmega 400
- 328 CFM
- Comparable models
- 20 of 70
See the checked facts and calculation notes
Match countThe count uses the current product-to-need assignments for “Wildfire smoke gets indoors”, “I have very little floor space”, and “I want it to react on its own”. A need with no documented match does not count.
Calculation noteThis median uses explicit smoke CADR figures. General maximum-airflow measurements are excluded. 20 of 70 models have comparable published figures for context.
| Product | Needs matched | Checked facts | Source records |
|---|---|---|---|
| Coway Airmega 300 |
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| |
| Coway Airmega 400 |
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Ready to choose?
Check the price. Read the owner reviews.
Open either model on Amazon to check the current price, customer reviews and delivery options.
Coway Airmega 300
A smaller square cabinet is easier to place
See price & reviews on AmazonCoway Airmega 400
You need more living-room 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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