A compact, quiet smart purifier for bedrooms, nurseries and home offices.
Amazon $112.99The Blueair Blue Pure 511i Max is the better air purifier overall, rated 3.9 to 3.4. The Blueair Blue Pure 511i Max leads on value and auto mode. The Coway Airmega 150 wins on filter cost. The Blueair Blue Pure 511i Max costs $73.30 less ($112.99 vs $186.29).
A quiet, good-looking purifier for a small bedroom or nursery. Bigger rooms need more airflow for the money.
Amazon $186.29Prices 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 Blueair Blue Pure 511i Max for value ($0.74 per cfm of smoke CADR vs $1.22 per cfm of smoke CADR) and auto mode (particle sensor and Wi-Fi app vs particle sensor, auto mode).
- Choose the Coway Airmega 150 for filter cost ($49.99 a year in filters vs $59.98 a year in filters).
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 | Blueair Blue Pure 511i Max | Coway Airmega 150 |
|---|---|---|
| Overall rating | 3.9/5 | 3.4/5 |
| Value 25% | 82 $0.74 per cfm of smoke CADR | 45 $1.22 per cfm of smoke CADR |
| Filter cost 20% | 58 $59.98 a year in filters | 68 $49.99 a year in filters |
| Quiet 20% | 80 48 dB at top speed (maker rating) | 78 48.3 dB at top speed (maker rating) |
| Efficiency 15% | 74 7.9 cfm per watt | 50 efficiency not certified (neutral score used) |
| Auto mode 10% | 100 particle sensor and Wi-Fi app | 70 particle sensor, auto mode |
| Warranty 10% | 0 1-year warranty | 0 1-year warranty |
Specifications
| Blueair Blue Pure 511i Max | Coway Airmega 150 | |
|---|---|---|
| Performance | ||
| Smoke CADR | 153 cfm | 153 cfm |
| Dust CADR | 159 cfm | 161 cfm |
| Pollen CADR | 174 cfm | 220 cfm |
| PM2.5 CADR | 156 cfm | - |
| CADR certified by | AHAM Verifide | Maker (AHAM AC-1 test) |
| Room size (AHAM) | 237 sq ft | - |
| Coverage (maker) | 1,138 sq ft | 214 sq ft |
| Noise | 19 to 48 dB | 20 to 48.3 dB |
| Efficiency | ||
| Efficiency (IEF) | 7.9 cfm/W | - |
| ENERGY STAR | Yes | No |
| Energy use | 114 kWh/year | - |
| Power at top speed | 17 W | 35 W |
| Filters | ||
| Filter | Particle + carbon filter with washable fabric pre-filter | HEPA |
| Activated carbon | Yes | Yes |
| Replacement | 511i Max filter (111179) | AP-1019C-FP filter set |
| Replacement cost | $29.99 every 6 months | $49.99 every 12 months |
| Yearly filter cost | $59.98/year | $49.99/year |
| Ionizer | Yes | No |
| CARB certified (ozone) | Yes | Yes |
| Controls and build | ||
| Air-quality sensor | particle | particle |
| Auto mode | Yes | Yes |
| Wi-Fi app | Yes | No |
| Fan speeds | 4 | 3 |
| Dimensions | 14.5 x 9.3 x 9.3 in | 18.5 x 13.4 x 6.5 in |
| Weight | 4.2 lb | 12.1 lb |
| Warranty | 1 years | 1 years |
