The dirt on air purifiers

Concerned about your indoor air? That’s exactly what some air-purifier makers are counting on. Even if no one in your household has asthma or allergies, manufacturers would like you to think that an air purifier will help you breathe easy. But some of the 40 models we’ve tested did little to rid a space of dust and smoke. And one, the LightAir IonFlow 50F Surface ($300, shown), did almost nothing.

This isn’t the first time we’ve tested this air purifier. Back in 2010 we said, “With no fan to aid airflow, the LightAir IonFlow 50F was about as effective at removing dust and smoke in our tests as having no purifier at all.” Our most recent tests found that time hasn’t improved the unit’s performance. It’s still a Don’t Buy: Performance Problem.

No air purifier alone will relieve asthma or allergy symptoms. That’s why we suggest you first take basic steps that could be more effective—such as banning indoor smoking, banishing pets from bedrooms, and opening windows when possible. We also advise against using models that produce even small amounts of ozone, a respiratory irritant that can aggravate asthma, even if they are effective cleaners. You can get similar or better air cleaning using filter-based products, which don’t produce any ozone. Two CR Best Buys, the Whirlpool AP51030K, $300, and the Hunter 30547, $260, were effective at removing dust and smoke even at the lower, quieter speeds you might want to use while snoozing or having a quiet conversation.

Whichever purifier you buy, be sure to follow the manufacturer’s recommendations for how often you need to change or clean the filter. See our buying guide to air purifiers for more information.