Coway Airmega 300: CADR, room size and running cost
Smoke CADR 315 cfm · Room size 488 sq ft (ENERGY STAR) · 314 kWh/yr ≈ $57.49/yr electricity (estimate)
Certified specs
| Smoke CADR | 315 cfm |
|---|---|
| Dust CADR | 333 cfm |
| Pollen CADR | 360 cfm |
| PM2.5 CADR | 324 cfm |
| ENERGY STAR effective room size | 488 sq ft (1.55 × smoke CADR, per 10 CFR 429.68) |
| Annual energy use | 314 kWh/yr |
| Integrated energy factor | 6 cfm/W |
| Smoke CADR per watt | 5.86 cfm/W |
| Ozone emissions (reported) | 0 ppb |
| Technology | Fan and Filter |
| Filter types listed | Composite Filter, Composite Filter |
| Automatic mode | None |
| Connected (app/Wi-Fi) | No |
| ENERGY STAR Most Efficient | No |
| Markets | United States, Canada |
| Date certified | 2021-10-01 |
| ENERGY STAR partner | Coway Co., Ltd. |
| Source | ENERGY STAR record 4512747 (also listed as record(s) 4512746, 4512745) · Product Finder page |
How many air changes per hour would it give?
Estimate: air changes per hour (ACH) = smoke CADR × 60 ÷ room volume, at the top fan speed used for the CADR test. Real-world ACH is usually lower (lower fan speeds, furniture, filter loading).
| Room | ACH, 8 ft ceiling | ACH, 9 ft ceiling | AHAM sizing |
|---|---|---|---|
| 100 sq ft | 23.6 | 21.0 | Meets AHAM 2/3 rule |
| 150 sq ft | 15.8 | 14.0 | Meets AHAM 2/3 rule |
| 200 sq ft | 11.8 | 10.5 | Meets AHAM 2/3 rule |
| 300 sq ft | 7.9 | 7.0 | Meets AHAM 2/3 rule |
| 400 sq ft | 5.9 | 5.2 | Meets AHAM 2/3 rule |
| 500 sq ft | 4.7 | 4.2 | Below AHAM 2/3 rule |
| 700 sq ft | 3.4 | 3.0 | Below AHAM 2/3 rule |
AHAM's 2/3 rule: choose a smoke CADR of at least 2/3 of the room's area (8 ft ceiling). By that rule this model suits rooms up to about 472 sq ft.
Estimated yearly electricity cost
| Where | Residential rate | Per year | Per month |
|---|---|---|---|
| Louisiana | 12.72¢ | $39.94 | $3.33 |
| U.S. average | 18.31¢ | $57.49 | $4.79 |
| California | 33.61¢ | $105.54 | $8.79 |
| Hawaii | 48.00¢ | $150.72 | $12.56 |
Estimate = 314 kWh/yr × rate. Rates: EIA Table 5.6.A, July 2026 (preliminary). Filter replacement cost is not included (data gap: not in ENERGY STAR data). Use your own rate and hours.
On battery during an outage (estimate): 314 kWh ÷ 5,840 active hours ≈ 54 W average, which runs slightly high because the annual figure includes standby. A 1,024 Wh portable power station at an assumed 85% inverter efficiency would run it about 16 h. Top fan speed can draw more. Try other stations in the runtime calculator on our power station site.
Similar CADR from other brands
| Model | Smoke CADR (cfm) | ENERGY STAR room size (sq ft) | Energy use (kWh/yr) | Est. electricity/yr* |
|---|---|---|---|---|
| Rainbow Luggable XXL | 306 | 474 | 75 | $13.73 |
| Rainbow Luggable XL Ultra | 333 | 516 | 81 | $14.83 |
| Blueair 4412311000 | 321 | 498 | 181 | $33.14 |
| Blueair 3332111100 | 283 | 439 | 193 | $35.34 |
| Levoit LAP-C511S-WUS | 301 | 467 | 194 | $35.52 |
| Midea 793K20A | 303 | 470 | 218 | $39.92 |
| Midea US-KJ500G-TB32 | 303 | 470 | 218 | $39.92 |
| Blueair 3432111100 | 339 | 525 | 227 | $41.56 |
*Estimate: ENERGY STAR annual kWh × U.S. average residential rate 18.31¢/kWh (EIA, July 2026 (preliminary)). ENERGY STAR's annual figure assumes 16 hours/day of operation under the DOE test procedure.
Compare this model side by side with any other · All Coway models
See Coway air purifiers on the manufacturer's site (plain link, not an affiliate link)
We have not tested this product. Figures are as listed in ENERGY STAR data retrieved 2026-10-17.