Coway Airmega 150
#4 in Medium roomsFull review
A quiet, good-looking purifier for a small bedroom or nursery. Bigger rooms need more airflow for the money.
Amazon $186.29$186.29
The Coway Airmega 150 and the KNKA APH4000 are evenly matched, rated 3.4 and 3.4. The Coway Airmega 150 leads on filter cost. The KNKA APH4000 wins on value and warranty. The KNKA APH4000 costs $86.30 less ($99.99 vs $186.29).
KNKA APH4000
#5 in Medium roomsFull review
A low-priced purifier for medium rooms up to about 350 sq ft. It has a sensor-driven auto mode, but filter costs add up if you follow KNKA’s replacement schedule.
Amazon $99.99$99.99
Prices were last checked October 22, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Coway Airmega 150 for filter cost ($49.99 a year in filters vs $143.96 a year in filters).
- Choose the KNKA APH4000 for value ($0.44 per cfm of smoke CADR vs $1.22 per cfm of smoke CADR) and warranty (2-year warranty vs 1-year warranty).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every medium rooms air purifier; a clear win is highlighted. How we rank explains each one.
| Factor weight | Coway Airmega 150 | KNKA APH4000 |
|---|---|---|
| Overall rating | 3.4/5 | 3.4/5 |
| Value 25% | 45 $1.22 per cfm of smoke CADR | 100 $0.44 per cfm of smoke CADR |
| Filter cost 20% | 68 $49.99 a year in filters | 23 $143.96 a year in filters |
| Quiet 20% | 78 48.3 dB at top speed (maker rating) | 50 noise at top speed not published (neutral score used) |
| Efficiency 15% | 50 efficiency not certified (neutral score used) | 29 4.3 cfm per watt |
| Auto mode 10% | 70 particle sensor, auto mode | 70 air quality (type not stated) sensor, auto mode |
| Warranty 10% | 0 1-year warranty | 25 2-year warranty |
Specifications
| Coway Airmega 150 | KNKA APH4000 | |
|---|---|---|
| Performance | ||
| Smoke CADR | 153 cfm | 226 cfm |
| Dust CADR | 161 cfm | 226 cfm |
| Pollen CADR | 220 cfm | 244 cfm |
| PM2.5 CADR | - | 226 cfm |
| CADR certified by | Maker (AHAM AC-1 test) | AHAM Verifide |
| Room size (AHAM) | - | 350 sq ft |
| Coverage (maker) | 214 sq ft | 1,695 sq ft |
| Noise | 20 to 48.3 dB | 22 dB |
| Efficiency | ||
| Efficiency (IEF) | - | 4.3 cfm/W |
| ENERGY STAR | No | No |
| Energy use | - | 304 kWh/year |
| Power at top speed | 35 W | - |
| Filters | ||
| Filter | HEPA | HEPA-type |
| Activated carbon | Yes | Yes |
| Replacement | AP-1019C-FP filter set | APH4000LX |
| Replacement cost | $49.99 every 12 months | $35.99 every 3 months |
| Yearly filter cost | $49.99/year | $143.96/year |
| Ionizer | No | - |
| CARB certified (ozone) | Yes | Yes |
| Controls and build | ||
| Air-quality sensor | particle | air quality (type not stated) |
| Auto mode | Yes | Yes |
| Wi-Fi app | No | No |
| Fan speeds | 3 | 4 |
| Dimensions | 18.5 x 13.4 x 6.5 in | 17.09 x 12.36 x 8.15 in |
| Weight | 12.1 lb | 9.7 lb |
| Warranty | 1 years | 2 years |