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33 guides.
The 45i is Alen's mid-size purifier: a strong claimed CADR, a choice of filters for different problems, and a lifetime warranty that only lasts as long as your filter subscription.
The 75i is Alen's large-room machine, built for open plan spaces up to about 540 sq ft at allergy-level air changes. It is quiet and efficient, but its CADR is Alen's own and it costs more than certified rivals.
Pollen, dust mite debris and pet dander are large particles that settle fast. An allergy purifier needs high pollen and dust CADR, a sealed HEPA filter and a place where you actually spend time.
For asthma, how a purifier cleans matters as much as how fast. We chose filter-only models listed as mechanical by California, sized to the room, with an option for smoke and odor gases.
A bedroom purifier has to clean the air on a speed you can sleep through. That means buying a size up, with a quiet low setting and lights that turn off.
For a room over 400 sq ft, only a purifier with more than about 300 cfm of certified smoke CADR keeps up. These five do, and one big Coway that is not AHAM listed.
A purifier can catch mold spores in the air and soften a musty smell. It cannot stop mold growing. Here are the certified picks for the first job, and what to do about the second.
An office purifier runs eight to ten hours a day while you work beside it. It needs enough certified airflow for the room, a fan you can talk over and filters that do not need weekly attention.
Pet dander is a light particle that stays airborne; pet hair is a heavy one that clogs filters. A pet purifier needs high certified airflow for the first and a pre-filter built for the second.
In a studio corner, a walk-in closet or a desk nook, floor space decides. These purifiers are the smallest we found that still clean the space properly, on AHAM's numbers.
Under $200 you can buy a purifier certified for a 390 sq ft living room. The trick is to compare certified airflow and filter cost, not the coverage number on the box.
One purifier that follows you, living room by day and bedroom by night, can beat two that sit still. These certified HEPA purifiers are light enough to carry and strong enough to matter.
The 200M is the version of Coway's Mighty that drops the ionizer. Same filters, same cheap yearly filter set, three manual speeds, and a sensor-driven Auto Mode.
The Airmega 400 is Coway's large-room machine: two filter sets drawing air from both sides, a smart mode that reads particles and light, and a five-year warranty. It is also expensive.
The Mighty has been the reference mid-size purifier for a decade. It is still cheap to run, but it is no longer in AHAM's directory, it carries an ionizer, and Coway has a successor.
A HEPA purifier sized for the room can reduce virus-carrying particles in the air. It cannot stop transmission on its own, and some technologies sold for germs carry risks of their own.
Dyson's Purifier Cool PC1 replaces the TP07 in Dyson's US range. It is a well-built fan with a sealed HEPA filter, but Dyson publishes no CADR, so you pay a premium without a certified number.
The HP1 is Dyson's current heater, fan and purifier, sold in place of the HP07. It earns its price only if you will use all three jobs; as a purifier alone, certified machines do more for less.
A bypass HEPA unit pulls part of the return air through a HEPA filter with its own fan, so it does not choke your furnace. EPA says most MERV 13 filters get close to HEPA results anyway.
The HPA200 is the HPA300's smaller sibling: two R filters instead of three, 200 cfm of certified smoke CADR, simple buttons. Honeywell still sells it, but Amazon now lists only its filters.
The HPA300 is the plain-box classic: lots of certified airflow for the price, simple buttons, no app and no sensor. Its catch is filter upkeep: three HEPA filters and four pre-filters a year.
Most purifier HEPA filters last 6 to 12 months; a few last four or five years. The right answer for you depends on run time and how dirty your air is. Here are the makers' own figures.
Most air purifier mistakes come from the box: a coverage number that assumes one air change an hour, a filter name that means little, and running costs nobody mentions. Here is the checklist we use.
IQAir's HealthPro Plus is the purifier hospitals and the cautious buy: heavy, well sealed, with a gas filter and a HEPA stage that lasts four years. IQAir also refuses to publish a CADR, which makes it hard to compare.
The Core 300-P is the small HEPA purifier most people start with. Its certified numbers fit a bedroom, not the 1,073 sq ft on the box, and its filters are cheap.
The Core 400S-P is the Core 300's bigger, smarter sibling: a laser particle sensor, auto mode and an app, with enough certified airflow for a living room up to about 360 sq ft.
The Vital 200S-P is Levoit's pet-household purifier: the most certified airflow in Levoit's mid-range, a side inlet that keeps fur off the filter, and a rectangular body that fits against a wall.
The MA-40 is AHAM listed with real airflow for its price and a lifetime warranty. Its weak points are a short filter interval, which makes running costs climb, and louder low settings than the best rivals.
Six air purifiers that earn their place on certified numbers: the right CADR for the room, sensible filter costs, and no marketing-only claims.
"True HEPA" is not a regulated grade. The real standards are the US Department of Energy's 99.97% at 0.3 microns and Europe's EN 1822 grades. Here is how to read a purifier's filter label.
A purifier's certified CADR is only reached if air can get in and out. Placement decides how much of that clean air reaches you. Here are the rules, in order of how much they matter.
Winix's 5500-2 was the default mid-size purifier for years. Its replacement, the 5510, keeps the thick carbon filter and adds Wi-Fi. Here is what the certified numbers say.
The AM90 is Winix's taller Wi-Fi tower. Its certified airflow matches the 5510, but its carbon filter needs replacing four times as often, and Amazon has had it out of stock.
