Coway Airmega 400S vs Airmega 400
The same hardware with Wi-Fi added — and only one of the two has a certified number attached to it. Here is every figure Coway publishes, and which of them anybody has checked.
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Coway publishes 328 smoke CADR and 3,120 sq ft at one air change an hour for the Airmega 400S, and no register has verified any of it. The Airmega 400 is the same machine without Wi-Fi, and it is certified — at 376 CFM across 583 square feet with 0.00 ppb measured ozone, figures better than Coway’s own claim. Buy the 400 unless the app is worth more to you than the evidence.
This page exists because the question people actually type is some version of “what is the Airmega 400S’s official CADR and room size” — and the honest answer has two halves that most pages collapse into one.
What Coway publishes for each model
Read on Coway’s own product pages, 2026-10-03. Every row below is Coway’s figure for both machines, and the two columns are identical except for the last three.
| Specification | Airmega 400 | Airmega 400S |
|---|---|---|
| Model code | AP-2015F | AP-2015E |
| CADR (Coway's own) | 328 smoke / 328 dust / 400 pollen | 328 smoke / 328 dust / 400 pollen |
| Advertised coverage | 3,120 sq ft at 1 ACH | 3,120 sq ft at 1 ACH |
| At 2 air changes | 1,560 sq ft | 1,560 sq ft |
| Power | 66 W | 66 W |
| Noise | 22~52 dB(A) | 22~52 dB(A) |
| Filter | Max2 set (carbon + HEPA), 1 year | Max2 set (carbon + HEPA), 1 year |
| Pre-filter | Washable | Washable |
| Size and weight | 14.8 x 22.8 x 14.8 in, 24.7 lb | 14.8 x 22.8 x 14.8 in, 24.7 lb |
| Wi-Fi and app | No | Yes, IoCare+ |
| Scheduling and timers | On-unit timer | Via the app |
| Remote monitoring | No | Yes |
What is certified, and for which model
Here the two columns stop matching. The Airmega 400 is in the ENERGY STAR database as AP-2015F, with figures that are not Coway’s:
| Specification | Certified figure | Coway's own claim |
|---|---|---|
| Smoke CADR | 376 CFM | 328 CFM |
| Dust CADR | 384 CFM | 328 CFM |
| Pollen CADR | 409 CFM | 400 CFM |
| Room size at 4.8 air changes | 583 sq ft | Not published |
| Annual energy use | 366 kWh | Not published |
| Air per watt | 6.1 CFM/W | Not published |
| Measured ozone | 0.00 ppb | Not published |
| Filter classification | Composite Filter | Described as HEPA |
Two things in that table are worth sitting with. First, the certified smoke CADR is 15% higher than Coway’s own published figure — this manufacturer understates its own machine, which is the opposite of the usual problem. Second, four of those rows exist only because a third party measured them: room size at the industry standard rate, annual energy, efficiency and ozone. Those four are precisely what this site ranks on, and for the 400S none of them exists.
The test that shows this is specific to the 400S
An obvious objection: maybe Coway simply does not certify its connected models. It does. The Airmega 450S (AP-2524C) is in the ENERGY STAR database, with figures identical to the non-smart Airmega 450 — 443 CFM smoke CADR across 687 square feet, 0.00 ppb measured.
So the certification of an S variant is something Coway does when it chooses to. The 400S’s absence is a fact about that model, not a quirk of how smart purifiers are handled. We cannot tell you why, and we are not going to guess — the full certified record on the Airmega 400 is what we can stand behind.
What you gain and what you give up
You gain real functionality. Wi-Fi, the IoCare+ app, scheduling, remote monitoring and the ability to see air quality when you are not in the room. For some households that is worth paying for, and this site has never pretended features are worthless — only that they do not move air.
You give up every verified number. No certified CADR, no certified room size at the rate sizing rules use, no certified annual energy, no measured ozone. On a site that sizes rooms with AHAM’s two-thirds rule, that last point matters practically: the certified 400 clears a room of about 564 square feet, and for the 400S we would have to compute the same figure from a manufacturer’s CADR that the register has already contradicted by 15%.
You usually pay more for the privilege. We do not print prices in prose because they move, but the 400S has sat above the 400 on both Coway’s own store and Amazon every time we have checked this year. You are paying a premium for the model with less evidence behind it.
What each one costs to run
Half the bill is identical and knowable. Both machines take the same Max2 filter set — Coway’s replacement listing is titled for the 400 and 400S together — at $129 for the pair on a stated one-year schedule. That is $129 a year whichever you buy, and it makes this one of only two machines on this site whose filter cost can be stated at all.
The other half splits. ENERGY STAR certifies the Airmega 400 at 366 kWh a year — $67 at the national average rate — which is a measured figure covering standby and real duty, not a wattage multiplied out. For the 400S there is no certified energy figure, so its annual electricity is not knowable; Coway publishes a 66 W rating and nothing else.
So the total cost of owning the Airmega 400 is $196 a year, stated. For the 400S it is that filter cost plus an electricity figure nobody has published — probably similar, since the hardware appears to be the same, but “probably similar” is the whole difference this page is about — what every manufacturer publishes about filter cost.
The wider pattern worth knowing
This is the third time this site has run into the same shape: the machine most people are searching for is the one with the least evidence. Coway’s best-selling AP-1512HH is in no register either, and Dyson publishes no CADR at all while outspending everyone on marketing — what we could and could not verify about Dyson.
The useful habit is small: before buying, find the model code on the box — not the marketing name — and search it in the ENERGY STAR or AHAM database. It takes a minute, and it is the difference between 328 CFM claimed and 376 CFM measured. In this case the check pays twice, because the certified machine is also the cheaper one.
Quick picks
The certified version of the machine you were looking at, and the two Coways either side of it.
| # | Product | Best for | Certified CADR | Price |
|---|---|---|---|---|
| 1 |  The certified version Coway Airmega 400 376 certified CFM across 583 sq ft, 0.00 ppb — the same machine, verified. | Large rooms, verified Coway | 376CFM smoke ENERGY STAR verified | |
| 2 |  If the room is bigger Coway Airmega 450 443 certified CFM across 687 sq ft, vacuumable pre-filter, 0.00 ppb. | Open-plan floors up to about 665 sq ft | 443CFM smoke ENERGY STAR verified | |
| 3 |  The popular one, unverified Coway Airmega Mighty AP-1512HH 233 CFM claimed, in no register, with an unmeasured bipolar stage. | The popular default, unverified | 233CFM smoke Manufacturer-claimed |
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What to buy instead
Coway Airmega 400
Coway · model Airmega 400 (AP-2015F)
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The Coway that is actually in a certification register: 376 certified smoke CADR, 583 square feet, zero measured ozone. If you want a Coway, this is the one with third-party numbers.
376 smoke / 384 dust / 409 pollen CFM · 380 PM2.5
- Certified room size
- 583 sq ft
- Advertised coverage
- 3,120 sq ft in 60 minutes
- Energy / year
- 366 kWh
- Electricity / year
- $67
- Air per watt
- 6.1 CFM/W
- Power draw
- 66 W
- Noise
- 22-52 dB(A)
- Measured ozone
- 0 ppb
- Filter class
- Composite Filter
- AHAM rule, 500 sq ft
- Clears it (334 needed)
No ionizer — filtration only
ENERGY STAR classifies this unit 'Fan and Filter', 0.00 ppb measured ozone.
Identical hardware to the 400S on every published specification, minus the Wi-Fi — and certified: 376 smoke CADR across 583 square feet, 0.00 ppb measured ozone, no ion stage, washable pre-filters on both faces, and the only fully published filter bill on this site at $129 a set. Our full review.
The honest con: no app and no remote monitoring, ENERGY STAR declines to classify its filter HEPA or HEPA-Type at all, and its filters cost more per year than its electricity.
Coway Airmega 450
Coway · model Airmega 450 (AP-2524B)
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687 certified square feet with zero measured ozone and a vacuumable pre-filter. The step between the Airmega 400 and the ProX, and the cheapest certified way past 600 square feet.
443 smoke / 445 dust / 450 pollen CFM · 444 PM2.5
- Certified room size
- 687 sq ft
- Advertised coverage
- 3,285 sq ft in 60 minutes
- Energy / year
- 389 kWh
- Electricity / year
- $71
- Air per watt
- 6.7 CFM/W
- Power draw
- 72 W
- Noise
- 23.6-57.7 dB(A)
- Measured ozone
- 0 ppb
- Filter class
- HEPA-Type
- AHAM rule, 650 sq ft
- Clears it (434 needed)
No ionizer — filtration only
ENERGY STAR classifies this unit 'Fan and Filter' and measures 0.00 ppb ozone. Coway's specification lists no ionizing stage.
443 certified smoke CADR across 687 certified square feet with 0.00 ppb measured, a vacuumable pre-filter and a choice of three filter sets. Its connected sibling, the 450S, is the S model Coway did certify. The full record on it.
The honest con: its published range tops out at 57.7 dB(A), the loudest we print, and Coway publishes no replacement filter price for it — so unlike the 400, its annual cost cannot be computed.
Coway Airmega Mighty AP-1512HH
Coway · model Airmega Mighty AP-1512HH
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The most-recommended air purifier in this category, and the one with no third-party CADR to check. Coway's own figures are good; at 77 watts it is also the thirstiest machine here for its output.
233 smoke / 246 dust / 240 pollen CFM
- Certified room size
- 361 sq ft
- Advertised coverage
- 1,748 sq ft in 60 minutes
- Power draw
- 77 W
- Noise
- 24-53 dB(A)
- AHAM rule, 350 sq ft
- Short (234 needed)
Bipolar device — fitted
Coway lists a 'Bipolar Device' as the fourth filtration stage. Because this model is in neither register, there is no independent ozone measurement for it — and Coway does not publish one.
Worth naming because it is the Coway most people end up with. Coway’s own figures are 233 CFM and 361 square feet, it documents a washable pre-filter and filter intervals, and it is genuinely well built.
Why it is not a pick: like the 400S it is in no register, and unlike the 400S it also ships a bipolar ionizing stage with no published ozone measurement from any source. The full record on it.
The verdict
Common questions
What is the official CADR and room size of the Coway Airmega 400S?
Is the Airmega 400S the same as the Airmega 400?
Is the Coway Airmega 400S certified?
Should I buy the 400S or the 400?
Does Coway certify its smart models at all?
Sources
- ENERGY STAR certified room air cleaners database
- AHAM VERIFIDE directory of certified room air cleaners
- Coway Airmega 400S specification
- Coway Airmega 400 specification
Figures were read on the dates shown against each source. If one has changed, or if we have got something wrong, tell us and we will correct the page.
Read next
- Pet allergiesCoway Airmega 400 Review376 certified CFM, 583 sq ft, 0.00 ppb and a washable pre-filter — plus the only complete running-cost figure on this site, because Coway publishes both halves.
- Pet allergiesCoway Airmega 400 vs Airmega Mighty AP-1512HH376 certified CFM and 0.00 ppb ozone against 233 claimed CFM and an unmeasured bipolar stage — from the same brand.
- Pet allergiesAre Dyson Air Purifiers Worth It for Pet Allergies?Dyson appears in neither certification register. We checked both live, quote Dyson's reasoning in full, and say what a pet household should do about it.