In any given night of sleep, most of us take between six and nine thousand breaths. With each of those breaths, we inhale countless particles, ranging from harmless dust to potentially harmful pollutants. For the immunocompromised or the just plain risk averse, there is an obvious solution: the home air purifier. For a couple hundred bucks, you can make sure the air in your house is as fresh as the sheets you just laundered.
There are an overwhelming number of air-cleaning devices on the market, all advertising various filtration methods. How do you find the best one?
Luckily, I've extensively researched the field of products, tested the extra features on a dozen of the most popular models, interviewed various experts in the field of indoor air quality and written up the definitive list of the best air cleaners around. Ready to buy an air purifier? Look no further.
A dozen of the most popular home air purifiers on the market.
David Priest/CNET
Before the recommendations…
Before getting into the details of which devices are best and why, it's important to understand the basic mechanisms that these products use to clean your air. To get a handle on these methods, I talked to Dr. Richard Shaughnessy, the Director of Indoor Air Research at the University of Tulsa.
According to Shaughnessy, most air cleaners run your air through a filter designed to catch particles you might otherwise inhale. These are usually High Efficiency Particulate Absorbing filters and they're designed to capture 99.97% of particles sized .3 microns or larger. HEPA filters reliably remove smoke (including from wildfires), pollen, dust and other particulate that pollutes home environments.
Activated carbon offers another type of filter, which captures odors and gaseous pollutants that can slip through a HEPA filter. "[Carbon filters are] good... to an extent," said Shaughnessy, "but they need to have a sufficient amount of carbon… You don't want breakthrough happening where the carbon becomes fully saturated and it releases what was captured back into the air."
According to multiple researchers I talked to, most consumer air purifiers simply don't have enough activated carbon to be an effective odor filter for more than a short period of time.
Another common type of air cleaning comes in the form of ionic filtering. These filters can be effective, according to Shaughnessy, but they come with a number of shortcomings: Some don't actually remove particulate from the home, but rather cause it to attach itself to surfaces around the home. Others must be cleaned consistently, or they might begin to emit ozone -- itself a pollutant.
While some ionic purifiers are effective and standards for them have risen significantly in recent years, the benefits they offer over a HEPA filter are in many cases negligible -- particularly given the risk they occasionally pose.
Besides the HEPA filter, the other important standard to keep an eye out for is the "AHAM Verified" Clean Air Delivery Rate, which tells you how much air the purifier can process in a given timeframe. Not every company uses this standard, but most do.
Recommendations get a little more complicated when companies don't list a CADR, or when they employ proprietary filtration methods.
Dyson's $550 air purifier doesn't offer a CADR rating at all.
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Best overall air purifier
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