Air Purifiers
HEPA air purifiers compared on smoke CADR, honest room coverage, filter grade, noise, and filter life, so you can size one to the room and not the marketing.
 Alen BreatheSmart 75i | 6.9 Excellent large-room performance and quiet, but the highest five-year cost here, and the lifetime warranty is tied to buying Alen's filters. | 350 CFM | 543 sq ft | True HEPA H13 | 51 dB | 12 mo |
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 Blueair Blue Pure 211i Max | 7.7 Huge airflow that stays remarkably quiet, but it is HEPA-type filtration with an ionizer and the proprietary filters are neither cheap nor long-lived. | 410 CFM | 636 sq ft | HEPA-type | 53 dB | 9 mo |
 Blueair Blue Pure 311i Max | 8.6 Among the most effective mid-size units testers have measured, and unusually quiet doing it, though the filter is HEPA-type with an ionizing assist. | 250 CFM | 388 sq ft | HEPA-type | 50 dB | 9 mo |
 Blueair Blue Pure 411a Max | 6.4 Cheap, tiny and genuinely quiet, but it only suits a small bedroom and the recurring filter cost is high for what it moves. | 141 CFM | 219 sq ft | HEPA-type | 46 dB | 9 mo |
 Coway Airmega 250 | 7.5 Reviewers who actually lived with it rate the cleaning and build highly, and it is cheap to keep fed, though the top two fan speeds are genuinely loud. | 249 CFM | 386 sq ft | True HEPA | 54 dB | 12 mo |
 Coway Airmega 400S | 8.2 Reviewers rate it above the Levoit rivals on build, pre-filter design and long-term confidence, but you pay a lot for that margin. | 328 CFM | 508 sq ft | True HEPA | 52 dB | 12 mo |
 Coway Airmega AP-1512HH Mighty | 9.2 A decade as Wirecutter's top pick for a reason: cheap filters, quiet real-world cleaning and a reputation for running for years without drama. | 233 CFM | 361 sq ft | True HEPA | 53 dB | 12 mo |
 GermGuardian AC4825E | 2.4 An aging design that took over an hour and a half to clear a test room and drew more power doing it; reviewers actively steer people elsewhere. | 99 CFM | 153 sq ft | True HEPA | 56 dB | 6 mo |
 Honeywell HPA100 | 3.6 Measured near 69 dB at full speed, far louder and less efficient than rivals that clean more air, with no sensor or auto mode. | 100 CFM | 155 sq ft | True HEPA | 69 dB | 12 mo |
 Honeywell HPA300 | 6.0 Lots of certified airflow per dollar, then nothing else: no sensor, no auto mode, and top speed is loud enough to drown out a TV. | 300 CFM | 465 sq ft | True HEPA | 71 dB | 12 mo |
 Levoit Core 300S | 8.0 The budget bedroom default: near-silent on sleep mode, very low power draw, and it beats pricier small units on cleaning per dollar. | 141 CFM | 219 sq ft | True HEPA H13 | 50 dB | 6 mo |
 Levoit Core 400S | 7.4 Capable and well-liked, with a good app and display, but the cheaper Vital 200S matches it and adds a washable pre-filter. | 231 CFM | 358 sq ft | True HEPA H13 | 52 dB | 6 mo |
 Levoit Core 600S | 8.3 Genuine large-room airflow for far less than the premium brands, with a better motor than earlier Levoits; six-month filters are the running cost. | 391 CFM | 606 sq ft | True HEPA H13 | 55 dB | 6 mo |
 Levoit Vital 100 | 5.4 Cleans slower than the cheaper Core 300S while drawing roughly double the power, so it is the wrong Levoit at almost any price. | 105 CFM | 163 sq ft | True HEPA | 50 dB | 6 mo |
 Levoit Vital 200S | 9.0 Clears a room faster than units costing twice as much, has a washable pre-filter and skips the ionizer, which is why HouseFresh keeps recommending it. | 250 CFM | 388 sq ft | True HEPA H13 | 54 dB | 12 mo |
 Medify MA-112 | 4.8 Moves enormous air, but costs about six hundred dollars, hits roughly 70 dB flat out, and needs two large filters every few months. | 594 CFM | 921 sq ft | True HEPA H13 | 70 dB | 5 mo |
 Medify MA-40 | 5.9 Real H13 filtration at a fair price, undercut by wildly optimistic coverage claims, an ionizer asthmatics should avoid, and filters due twice a year. | 239 CFM | 370 sq ft | True HEPA H13 | 53 dB | 5 mo |
 Winix 5300-2 | 7.8 Cleans identically to its more expensive siblings for around half the money; you give up the remote and the carbon filter needs changing more often. | 232 CFM | 360 sq ft | True HEPA | 58 dB | 12 mo |
 Winix 5500-2 | 8.4 Winix discontinued it in 2025, so the value benchmark is now a stock-clearance buy, but it still clears a room fast and filters are promised until 2032. | 232 CFM | 360 sq ft | True HEPA | 58 dB | 12 mo |
 Winix AM90 | 7.9 Wirecutter got the same strong cleaning here as from its runner-up Winix, and it is still sold, though it draws more power and the display never dims. | 233 CFM | 361 sq ft | True HEPA | 55 dB | 12 mo |
How the AI score works, and who wrote it
A language model rated these, not a test lab. Every score from 1 to 10 is an AI assessment of how good the product is against the other 20 in this comparison, formed from the specifications we verified plus the published lab reviews and owner reception found while researching each one. Nobody at Slopsheets listened to, wore or plugged in any of it.
It weighs the things a spec table cannot show: how a product is actually reviewed, how well the software works, build quality, and what you get for the money. That is deliberate. An earlier version of this column was pure arithmetic on the table and it ranked a bundle of cheap boxes above a class-leading single unit, because counting hardware is not the same as judging it.
Treat it as an informed starting point and read the sourced comparison, not as a verdict. The score is relative to this comparison only, so it means nothing across categories, and it carries no price, star rating or review count. Every specification behind it is sourced and checked; the score on top of them is opinion.