tldr; Community favorite for whisper-quiet operation and great for pet owners.
Check pricesScores based on sentiment analysis of topic-related comments
Best praise vs top criticism for Smart Air Blast
“I haven't heard back from you, but wanted to give you a few options. I've copied this from another one of my comments. For a newborn baby, you need very quiet operation in the nursery since it's a smaller space. To achieve this, you can either buy multiple air purifiers per room and run them at lower speed settings or you can buy a fairly quiet & oversized unit. Noise or sound level disparity—that is, the difference between real world sound levels and what's listed in the specs—is a problem for many purifiers. This subreddit has received good feedback on the **Smart Air Blast MKII** being very quiet. The **Coway Airmega ProX** is an excellent unit, but I don't know if real life sound levels match what's in the specs. I've left out Winix as they tend to be quite loud on high and they're not considered as high quality as Coway. # Oversized and Very Quiet **Coway Airmega ProX** * Room Size: 4.8 ACH at 886 sq. ft. * Other ACH: 21 ACH at 200 sq. ft. * Particulates Filtration: HEPA H13 * Sound Levels: 23 - 46 db(A) * Dust CADR: 580 CFM * Pollen CADR: 450 CFM * Smoke CADR: 568 CFM * Features: Locking wheels, Smart Modes, "Max2" Filter Replacement Indicator, Pre-Filter Maintenance Indicator, PM & Air Quality Unit Indicator, Air Quality Indicator * Price: Currently $796.00 in White; $619 in Mocha Beige at [Coway](https://cowaymega.com/products/airmega-prox) **Smart Air Blast MKII Air Purifier** * Air Changes per Hour (ACH): 4.8 ACH at 1,875 sq. ft. * Other ACH: 45 ACH at 200 sq. ft. * Particulates Filtration: H13 HEPA Filter (150 sq. ft. of filter surface area) * Dust CADR: 559 CFM * Other CADRs not given * Sound Levels: 29 – 37 – 43 dB * Features: Locking casters and metal housing * Price: $929 at [SmarterHEPA](https://www.smarterhepa.com/products/smart-air-blast) # Smaller Particulates Units (you could use multiple purifiers in the room if top speed is too loud) **Coway Airmega 230** * Air Changes per Hour: 4.8 ACH at 403 sq. ft. * Particulates Filtration: HEPA H13 * Dust CADR: 294 CFM * Pollen CADR: 302 CFM * Smoke CADR: 273 CFM * Sound Levels: 21 - 51 dB(A) * Price: Currently $209 at [Coway](https://cowaymega.com/products/airmega-230) **Coway Airmega 240** * Air Changes per Hour: 4.8 ACH at 403 sq. ft. * Particulates Filtration: HEPA H13 * Dust CADR: 292 CFM * Pollen CADR: 343 CFM * Smoke CADR: 282 CFM * Sound Levels: 21 - 51 dB(A) * Price: Currently $239 - $243 at [Coway](https://cowaymega.com/products/airmega-240) **Coway Airmega 400** * Air Changes per Hour: 4.8 ACH at 650 sq. ft. * Particulates Filtration: HEPA H13 * Dust CADR: 358 CFM * Pollen CADR: 450 CFM * Smoke CADR: 285 CFM * Sound Levels: 22 - 52 dB(A) * Price: Currently $349 in White at [Coway](https://cowaymega.com/products/airmega-400?variant=33436457009287)”
“Of those 4, the BlueAir 211+ is a powerhouse. The Numinoviwhatever is a generic brand that I'd avoid. The white Honeywell is severely undersized for the room. The black one is likely undersized as well. Remember that even the biggest and best purifiers (the BlueAir 211+ cleans more air than anything but a Coway 400 or a Smart Air Blast) really only effectively clean 300-400 square feet on their own, so you will likely need multiple units.”
222 Reddit opinions analyzed • Last updated 2/24/2026