Can air purifiers help you breathe easier?
While some experts, including the EPA, question whether or not air purifiers can significantly improve health, there's no question that many are effective in their primary role of removing particles and allergens from the air, and in some cases reducing odors as well. The best guidance suggests that taking steps to eliminate sources of irritants in the first place rather than cleaning the air afterwards is more effective still, but air purifiers can be a reasonable alternative if that's not possible or desirable. Even so, air filters should be used in conjunction with other allergen-control strategies such as ventilation and daily HEPA vacuuming for the best results.
Air purifiers do their work using different technologies, and some use multiple technologies, to deal with airborne pollutants. HEPA air purifiers use pleated high-efficiency particulate arresting (HEPA) filters to mechanically trap particles, along with a fan to pull air through the filter. By a wide margin, reviewers say this type of air purifier is the most effective. These models don't produce any ozone. Because they use fans, they can be noisy, but some are quieter than others. Be on the lookout, however, as not every air purifier that relies on mechanical filtration uses true HEPA filters.
Some air purifiers use electronic technology in place of or in addition to a mechanical filter. Electronic ionizers work by reversing the charge of particles in the air. The charged particles are then passed back out to the room where they are attracted to objects such as clothing, walls, floors and furniture. In effect, particles are removed from the air and deposited on your furnishings and clothing. You need to dust and vacuum to actually remove allergens from the room and prevent them from being reintroduced into the air. Some air purifiers have an electrostatic precipitator that works by putting a charge on particles and then collecting those using oppositely charged metal plates.
While both types of electronic air purifiers are effective for collecting particles as small as .1 microns, they can also produce a small amount of ozone, a lung irritant, though typically at levels below the standard set as safe by Underwriters Laboratory and by government agencies. Some electronic air cleaners put a small charge on a mechanical filter to help it collect particles more effectively. With that type of air cleaner, the charge is low enough that measurable amounts of ozone are not produced.
While ionic and electrostatic air purifiers emit small amounts of ozone as a byproduct, ozone generators sold as air purifiers emit high levels intentionally to neutralize chemical irritants and odors. Research has shown that while this can be effective, it's also fairly dangerous. The best advice we found is to avoid ozone generators altogether. For more information, see our discussion of air purifiers and ozone elsewhere in this report.
Another alternative is to consider a whole-house furnace filter. These aren't air purifiers; they simply replace your regular furnace filter. Filters such as the Filtrete Healthy Living 1900 (Est. $20 each and up) do an outstanding job trapping dust and pollen in one leading test, and they do a good job with smoke. Filters need to be replaced every three months otherwise their airflow, which is excellent in testing when clean, could be reduced.
It's important to note that, with the exception of ozone generators, none of the mechanical or electronic air purifying techniques above are particularly effective against chemical gases and odors. Some air purifiers add some type of chemical filtration -- typically activated carbon -- to deal with those irritants. The most effective of those sell for a premium price compared to the majority of air cleaners, but if you suffer from chemical sensitivities, they could be worth every penny.
Finding the best air purifiers
To find the top performing air purifiers, we consult professional reviews, such as those from ConsumerReports.org and The SweetHome.com. We also consider whether or not an air purifier has been submitted for testing and has had its ratings certified by the Association of Home Appliance Manufacturers (AHAM). Blogs created by allergy sufferers such as such as Ed Sherbenou of Air-Purifier-Power.com provide additional and often helpful guidance as well. Rounding things out, we analyze the hundreds and sometimes thousands of user reviews some air purifiers have garnered at sites like Amazon.com, HomeDepot.com, AllergyBuyersClub.com and elsewhere. Armed with that information, we consider factors such as performance, ease of use, noise and how costly an air purifier is to both buy and run to find the top choices and the best values.
Elsewhere in this report:
Air Purifiers and Ozone: Some air purifiers emit large amounts of ozone to neutralize odors and chemicals in the air. They work, but don't buy one anyway. Here's why.
Best Air Purifiers: The best air purifiers sell for a premium price, but they are the most effective, particularly against chemical gases and odors. These are the best choices.
Cheap Air Purifiers: These air cleaners won't do much to remove odors, but the best are every bit as effective against allergens and other particle pollution as the very best -- and priciest -- models.
Best Small Air Purifiers: If you just need an air purifier for a small bedroom or similar space, these low cost models are surprisingly effective.
Furnace Filters and UV Air Purifiers: Looking for an alternative to a room-sized air cleaner? Here's one thing to try, one thing to avoid, and a few hints that might help make for easier breathing no matter what you opt for.
Buying Guide: Not sure where to start in your hunt for an air purifier? These helpful hints can put you on the right path.
Our Sources: These are the expert and user reviews we consulted to find the top air purifiers in all prices and capacities. They are ranked in the order of their helpfulness and expertise.