There are myriad good reasons to own an air purifier. While they’re most commonly purchased to help relieve allergies related to dust and pets, buying an air purifier is also an extremely practical decision if you live in an area with increased risk of wildfire smoke. (Especially when, according to Michele Ann Cassalia of the Asthma and Allergy Foundation of America, the indoor level of pollutants can be two to five times higher than the outdoor levels.) Then there are the everyday, less-obvious allergy triggers to consider. “We’ve seen many examples in homes and offices where small changes like new furniture, air fresheners, cooking, [or] cleaning significantly impact the health of the air around you,” says Nic Barnes, chief marketing officer for the air-monitor company Awair. To identify the best air purifiers out there — and understand what to look out for when choosing between models — we asked seven experts to share their favorites. Here are their suggestions.
What we’re looking for
Filter type: For the best performance, all of our experts say that HEPA (high-efficiency particulate air) filters are considered the gold standard in the industry. They’re certified by the U.S. Department of Energy to eliminate 99.97 percent of particles as small as 0.3 microns, which, according to Asriani M. Chiu, a pediatric allergy and immunology specialist at the Medical College of Wisconsin, includes mold and animal dander. Some brands use an even newer type of filter — photo-electrochemical oxidation (PECO) — which supposedly filters down to 0.1 microns, but its efficacy has yet to be proven. In general, the experts prefer HEPA filters over electronic or ionizing devices that release ozone into the air, which can actually irritate asthma symptoms.
Coverage range: A common misconception some people have is that one air purifier will clean the air in an entire home, says Dr. John McKeon, CEO of Allergy Standards Limited. “Air purifiers are room-specific,” he adds, “and it’s very important to choose a product designed to clean the room size it will be used in.” Helpfully, all air purifiers list their maximum square-footage rating on their packaging: To measure the square footage you need to cover, simply multiply the length and width (in feet) of your space.
Noise level: As with all air-modifying appliances, from fans to air-conditioning units to humidifiers, the sound volume you’re willing to put up with is an important consideration. Below, we’ve listed the decibels of each device — for context, know that a whisper is generally around 30 decibels, while the noise of a regular conversation tends to average out closer to 60, according to the CDC.
Best overall air purifier
HEPA Filter | 815 square feet | 21–46 dB
This purifier — which manages to cover a very large space at a relatively quiet noise level — received more nods from our experts than any other on this list. Along with its particle-eliminating HEPA filter, an activated-carbon layer also absorbs gaseous compounds in the air, which Mitchell Grayson, a physician specializing in allergies and asthma, says is particularly helpful when it comes to eliminating smoke odors. The unit’s low-profile design means it can either stand on its own or be mounted on a wall, and the device also includes an air-quality indicator, as well as a light sensor that automatically transitions the unit to a lower power (read: quieter) mode when it’s time for bed.
Barnes is also a fan of the purifier, noting that it filters both fine dust and volatile organic compounds, the off-gases released by household materials like wall paint, upholstery, and varnishes. Cassalia, meanwhile, appreciates that it’s been certified by the Asthma and Allergy Foundation of America, based on third-party testing performed and reviewed by the foundation and the independent certification company Allergy Standards Limited. For $20 more, you can also get a Wi-Fi-enabled version, which has a connected app that lets you check your room’s air quality wherever you are and set the purifier to a daily schedule while you’re away.