How We Determined the Best Air Purifiers of

If you’re ready to bulk up your arsenal in the battle against indoor air pollution, an air purifier can help. Simply put, air purifiers trap, remove and, in some cases, destroy airborne contaminants, leaving the air cleaner and more “pure.”

But shopping for an at-home air purifier can be overwhelming, to say the least. There are countless options, each touting different benefits. And it’s easy to be intimidated by all the technical terms and scientific jargon. Plus, it can be difficult to separate marketing ploys from actual facts.

Don’t worry: That’s where we come in. Our experts sorted through all the research and data to determine what’s most important in the search for the best home air purifiers, then set to work determining which products get closest to meeting that criteria. Here are some of our top considerations in the hunt for the best air purifier:

1. Safety
While most air purifiers can be harmless additions to your home, there are a few types that can actually be harmful to your health. Here’s a look at the air purifiers you should avoid, and why:

Ozone Generators & Ozone Purifiers
These devices intentionally create ozone, which can change the chemical composition of particles and gasses in the air. Manufacturers of these types of devices claim that through this chemical interaction, ozone helps mask odors and clean the air. However, several federal agencies have established exposure limits to ozone because of its adverse effects on human health—inhalation of even small amounts of this gas can cause coughing, chest pain, throat irritation, shortness of breath and increased risk of respiratory infection. And the ozone concentrations required to be even just somewhat effective in removing pollutants from the air are well above those deemed safe by public health standards. For this reason, we strongly recommend consumers avoid ozone generators.

Ionizers & Electrostatic Air Purifiers
Unlike ozone generators, electronic air cleaners like ionizers, electrostatic precipitators, hydroxyl generators and UV light cleaners don’t purposely create ozone. But they can emit ozone as a byproduct, which means they can be just as harmful. Thus, we recommend avoiding these types of air purifiers—and any other type that creates ozone.

Our Recommendation
Avoid any technology that emits ozone deliberately or as a byproduct, and turn off the ionizer option on any air purifiers that include this technology. Opt instead for air purifiers that contain filters that remove small particles or gases from the air without emitting ozone, like:

• High-efficiency particulate air (HEPA) filters—found in AirDoctor and NuWave
• Activated carbon filters—found in AirDoctor and NuWave
• Photo Electrochemical Oxidation (PECO)—found in Molekule

2. Performance
Aside from safety, probably the most important consideration when shopping for the best home air purifier is how well it actually works.

It’s important to keep in mind that no air cleaner or filter will eliminate all of the airborne contaminants in your home. And, most filters are designed to filter either particles or gases, not both. That said, there are varying degrees of efficacy across different air purifiers.

Any air cleaner that has a HEPA filter has been tested and approved by the nonprofit Institute of Environmental Sciences and Technology. HEPA filters are designed to clear out at least 99.7 percent of particulates that are 0.3 microns or larger in size (for reference, a micron—or a micrometer, is about one twenty-five thousandth of an inch, if you can wrap your brain around that). Keep in mind that the efficacy of these purifiers in a home setting is actually less since new pollutants are constantly emerging.

For purifiers designed to filter particles, the Clean Air Delivery Rate (CADR) is a good gauge of efficacy. The CADR is a standardized performance system that rates the effectiveness of an air purifier in removing three different types of pollutants representing three different size particles: Pollen, dust and smoke. The higher the CADR test numbers, the better the unit’s ability to purify indoor air.

Here’s a look at the particle types that are assessed, the limits for each rating, and how our top two picks measure up:

While there are no widely used performance rating systems for portable air cleaners or filters designed to remove gases—the CADR system applies to particle removal only, research suggests that activated carbon filters can capture gases. Activated carbon filters with large amounts of surface area are likely to catch more contaminants, provided the filters are changed once saturated. So, if your aim is to remove both particulate matter as well as gases, your best bet is an air purifier with a high CADR and an activated carbon filter, like an AirDoctor or NuWave.

Beyond that, taking a look at the research on a product level is a good way to determine efficacy. Many of the best air purifier brands, like AirDoctor, NuWave and Molekule have invested in third party scientific studies conducted in laboratory settings to determine their effectiveness at removing specific contaminants. AirDoctor, for example, uses a proprietary variation of HEPA filters in their purifiers, which have been independently tested to remove up to 100% of particles at 0.003 microns in size—100 times smaller than the HEPA standard. A study conducted on NuWave’s OxyPure purifier demonstrated that within 30 minutes, 100 percent of smoke, dust and pollen particles were removed from the air.

3. Coverage
Some air purifiers are designed to clean small rooms while others can effectively purify a much larger space. Of course, a larger coverage area often comes with a higher price tag so you’ll want to keep in mind the square footage of the space you intend to purify as you shop for the best air purifier.

In addition to helping you get a read on how well a purifier will work, the CADR referenced above can also help you select an air cleaner based on the size of the area in which you’ll be using it. The higher the CADR, the more particles the air cleaner will remove and the larger the area it can serve. Note: The CADR is typically measured at the air cleaner’s highest speed.

Here’s a look at the coverage you can expect from our top three air purifier picks:

4. Noise Level
If you’re shopping for an air purifier for your bedroom, office, nursery or other preferably quiet space, the last thing you need is a disruptive machine cranking away in the corner.

Many air purifier manufacturers include a noise rating on their website or product packaging. Of course, the higher the fan speed you use, the more noise you’ll get. If you prefer a little background noise, look for an air purifier white noise setting.

All of the products on our list of the best air purifiers are quiet enough to not be disruptive—AirDoctor uses exclusive Professional WhisperJet fans that are 30 percent quieter than the fans found in most other air purifiers, NuWave OxyPure is a quiet 30 decibels at its lowest setting, and Molekule ranges from 41 to 65 decibels, depending upon the model. For reference, a noise level of 40 decibels is roughly equivalent to the level of noise generated by your refrigerator; a dishwasher is around 70, according to the Centers for Disease Control and Prevention (CDC).

5. Air Purifier Price
Air purifiers can range in price anywhere from $200 to $1000+, depending upon the brand, model and accessories included. Many of the best air purifier brands run frequent promotions that bring the price down significantly, so you’ll want to keep an eye out for those.

Here’s a look at pricing for our top three picks on the list of best air purifiers:

In addition to the cost of the air purifier itself, there are additional expenses you’ll want to account for as you make your decision. Filters will need to be replaced regularly for most purifiers. How often you’ll need to replace them and at what cost will depend on the space and frequency with which you use your purifier. Generally speaking, you’ll typically need to replace your HEPA filters once a year, and around every three to six months for activated carbon filters.

The good news is that some of the best air purifier brands like Molekule offer a subscription service for filters, which comes with a pretty generous discount. And, other brands like NuWave provide reusable, washable filters, which can help reduce this expense as well.