These Expert-Approved Air Purifiers Deliver Cleaner Air in Every Season

Air purifiers are on the list of continuously-tested products at the Good Housekeeping Institute. Throughout the year, our product experts keep tabs on the marketplace to identify the best air purifiers that you’re most likely to find at stores and online.

Next, we identify brands that have performed the best and proved the most reliable through more than a decade of air purifier testing at the GH Institute. We also consider newer brands with unique features or innovations.

Based on an extensive preliminary review of technical data, including claimed coverage area and type of filtration, our review team selected various models for hands-on testing, which took place both in our Lab and homes, the latter allowing us to test how they performed in real-world conditions.

Controlled Lab tests measured an air purifier's ability to capture specific contaminants, such as smoke and other VOCs (volatile organic compounds). At-home testing checked for general improvement of freshness, as well as overall usability.

To identify the ideal air purifier for your needs, consider the following factors:

✔️ Coverage area: Manufacturers typically list how much square footage a purifier is designed to cover. You might see multiple areas listed, say, one for the coverage provided in one hour and another for the coverage provided in five hours. Our experts recommend paying attention to the lower number since you'll likely want a device that delivers quick, repeated air cleaning.

✔️ Filtration: Most top-performing air purifiers use mechanical filters with a dense web of fine fibers that trap particles from the air as it is pushed through by a fan.

• True HEPA (High-Efficiency Particulate Air) filters use a very fine mesh certified to capture 99.97% of particles measuring at least 0.3 microns (and in some cases down to 0.1 microns) in diameter. Our bottom-line advice is that the best cleaning power comes from a true HEPA filter.
• "HEPA-like" filters have not been certified to meet that standard. Some air purifiers also have a pre-filter designed to capture dust and other larger particulates. Our experts like this feature.
• Other filtration technologies are harder to evaluate, including those that incorporate activated carbon and ultraviolet light. We don't test these technologies specifically, so we can't attest to their efficacy.

✔️ Operating costs. The main consideration here is the price of replacement filters, which can range from $20 or less to $100 and up. Since you might need to replace the filters a few times a year, depending on your home's air quality, the expense can add up.

✔️ CADR: Short for "clean air delivery rate," CADR is an industry measure of how much clean air the purifier produces in a given test environment for various pollutants; it is usually reported in cubic feet per minute. The rule of thumb is that the CADR should be at least two-thirds of the area that the air purifier will be cleaning. So if your room is 300 square feet, look for a CADR of 200 or higher. Not all manufacturers list CADR, but we list it with the specs in our product reviews for those that do.

In short, yes, air purifiers work. To clean the air, these appliances use filters and fans to remove particles and circulate the purified air back into the room. “Air purification is often used as part of a comprehensive treatment plan in the management of respiratory diseases,” says Derek Damin, M.D., assistant professor of clinical medicine at Vanderbilt University Medical Center.

People suffering from allergies or asthma might find air purifiers with HEPA filters particularly helpful because they remove common allergens and fine particles (99.97% of those measuring 0.3 microns in diameter in a lab setting, according to industry standards) from the air.

Not all air purifiers meet that high bar. For example, the much-hyped, sleek-looking IKEA Förnuftig can only capture 99.5% of smaller airborne particles. Even air purifiers that excel at removing particles like dust, smoke, and pollen are limited in their ability to capture smaller toxins, such as those from cleaning products and paint.

One more thing to note: The effectiveness of air purifiers in real-world situations likely won’t mimic those of controlled conditions in a lab. That means it can be difficult to measure an air purifier’s true efficacy or how it will perform in your home.

For best results, place air purifiers as close as possible to the source of pollutants in your home. In the kitchen, for example, position it near the cooktop, where it will help capture odors and fumes. We also recommend keeping an air purifier in the bedroom, close to the bed, where it will filter out contaminants from the air you breathe while you sleep.

Some consumer testers liked the "white noise" effect of an air purifier's fan, but if you're sensitive to sound, choose a model with quiet operation, like the top-rated Blueair. We use a sound meter (pictured) to perform this evaluation.

Always position air purifiers away from walls and other objects that could impede airflow. The more circulation, the better, to allow your purifiers to pull in as much contaminated air as possible.

Microscopic particles in smoke can trigger a range of health issues, from burning eyes to chronic lung disease, according to the U.S. Environmental Protection Agency, but "generally, outside pollution or smoke or temporary bad air isn't a constant concern for bystanders," says Ryan Roten, D.O., an emergency medicine doctor with Redlands Community Hospital in California.

If you're still concerned, Dr. Roten notes that a HEPA filter-equipped purifier is once again your best bet: “Anything that has a true HEPA filter in it is probably adequate enough to filter out most of the large particles that would be concerning,” he said. “Most of the smoky smell will also be addressed.”

✔️ Cleaning: Apart from wiping down the housing every now and then, cleaning the exterior of the device is minimal. However, the filters that do the dirty work inside an air purifier require regular attention. Whether made of paper, fiber, or mesh, the filters should usually be cleaned and/or replaced every few months or so (check the owner’s manual for specific recommendations). Some filters are reusable, but they require meticulous maintenance, so you don't usually find them on the most effective air purifiers. One exception is models with a washable pre-filter, designed to capture large particles before they reach the primary filter; this feature can cut operating costs by extending the life of the main inner filter.

✔️ Operation: For maximum efficacy, run the air purifier all the time when you’re home. Our picks are all UL-certified for safety, though as with any electrical device, be mindful of fire hazards like frayed wires. In areas where noise is a factor, like a bedroom, you could operate the machine on high when you’re out of the room, then drop it to a lower fan setting before going to sleep. It’s also best to keep windows closed, so the unit isn’t cleaning the air from outside or other parts of the home. And make sure airflow to the device isn’t obstructed by furniture, curtains, or other objects.

Dan DiClerico has extensively tested and written about air purifiers for more than 25 years. He has also spearheaded numerous investigative reports on the topic of indoor air quality, working closely with outside experts from government, industry, and the home services sector. As director of the Home Improvement & Outdoor Lab at the Good Housekeeping Institute, DiClerico oversaw the latest round of air purifier testing in our Labs and the continuous in-home, survey-based consumer testing that allows us to evaluate these devices in real-world conditions.

Nikolas Greenwald, data engineer at the GH Institute, contributed in-Lab testing of air purifiers for this report. Greenwald regularly evaluates the top performers and newest entries in the sector to find the best ones on the market. He has a bachelor's degree in chemical engineering and applies his knowledge of fluid dynamics and filtration processes to finding strong contenders in the home HVAC space.