Air purifier

Air Purifiers Buying Guide

Americans spend more than $350 million each year on room and whole-house air purifiers-also known as air cleaners-mostly in the hope that they'll ease the symptoms of asthma and allergies. But there's little medical evidence that any air cleaner alone can do that effectively.

Features

Whole-house air filters generally include a range of standard sizes, with some that adapt to fit different-size filter-box or return-air openings. Room air cleaners usually use a fan to pull air into the unit for filtration. But don't expect a wide array of bells and whistles. Here are the air purifier features to consider.

Fan  | Servicing indicator  | Dust sensor and air-quality monitor

Fan

Most room air cleaners use a fan to suck in air. Those without a fan run more quietly, but the ones we tested worked poorly.
 

Servicing indicator

A clogged air cleaner works inefficiently. You should remove and wash an electronic precipitator's collector-plate assembly every month or so. (You can do it in the sink or tub or put it in a dishwasher.) In most room and whole-house models that use an electronic precipitator, and in whole-house models that use a HEPA filter with ionizing circuitry, an indicator light lets you know when it's time to replace or clean the filter.
 

Dust sensor and air-quality monitor

In some room models, these raise or lower the fan speed automatically. But we were unimpressed with those we tested. They didn't kick in until pollutant levels were high, and then they shut off before the levels dropped sufficiently.
 
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