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15 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.
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.
A dorm purifier has to fit a shared room, a student budget and the college's appliance rules. These AHAM-listed picks do, and none relies on an ionizer.
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.
Pollen, dust mite debris and dander are mostly large particles, which MERV 12 and 13 filters catch at 90% or more. Our top allergy pick is the Filtrete MPR 1500 (MERV 12).
EPA suggests MERV 13 or the highest your system can handle. Our top pick is the Filtrete MPR 1900, a MERV 13 1-inch filter; here are five more for different systems and budgets.
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.
Every 60 to 90 days is the usual guidance for 1-inch filters, and Filtrete says at least every 90. Pets, allergies, renovation and smoke shorten it; deep media cabinets lengthen it.
MERV 13 catches the most fine particles and is what EPA suggests; MERV 11 is the safe middle; MERV 8 is for dust and restrictive systems. Here is the table and how to choose.
PM10 is every inhalable particle up to 10 micrometers; PM2.5 is the fine fraction inside it. The fine fraction is the bigger health concern, but the coarse part is the dust and pollen you can see.
If you cannot see light through it, it is gray all over, or the system is struggling, change it. EPA says an overloaded filter will not work well and can send air around the filter.
Six air purifiers that earn their place on certified numbers: the right CADR for the room, sensible filter costs, and no marketing-only claims.
Dry air can irritate the nose and throat, and moister air can ease a stuffy nose. A clean cool mist humidifier at 40 to 50% helps; a dirty one or too much humidity makes things worse.
