Air Purifier Review

Measuring performance of air purifiers

Air purifier recommendations from ConsumerGuide.com appear to be based on factors such as appearance, features and price of replacement filters. These criteria might be more important if all home air cleaners worked equally to clear the air of allergens like pet dander, dust and smoke. However, according to the only two organizations that test air purifiers thoroughly, performance varies greatly, so test results are especially important when it comes to identifying the best air purifiers. Be aware that while air purifier manufacturers often tout testing data in their advertising, the vast majority of these studies are sponsored and paid for by the manufacturer.

Consumer Reports magazine and online retailer Air-Purifiers-America.com are the only two review publications that test how well air purifiers remove airborne allergens. Unfortunately, these sources test air cleaners in different ways, and they don't always test the same models. Consumer Reports does the most controlled testing of home air cleaners, using a sealed test room with carefully measured particles of dust and smoke injected into the chamber. Air purifiers are evaluated on how well they remove dust and smoke from the air at set time intervals, running at both high and low speeds. The noise level of each air cleaner is also measured.

Air-Purifiers-America.com, on the other hand, tests home air purifiers in an office environment, with closed doors and windows and ventilation turned off, but with other variables present, like natural air currents and objects in the room. The company says that this type of testing better simulates normal use. Tested air cleaners are measured for particle removal close to the air purifier and in the center of the test room. Each air cleaner is tested on high speed. Noise level does not factor into the ratings at Air-Purifiers-America.com; editors say air purifier performance matters most and noise issues should be secondary.

We need to mention that these different test methods produce different results for several air purifiers, including the IQAir HealthPro Plus (*Est. $900), which receives the highest rating at Air-Purifiers-America.com and is one of the most highly regarded air cleaners in other reviews. In the sealed-chamber tests at Consumer Reports, however, the IQAir HealthPro Plus home air cleaner isn't a standout.

We contacted Air-Purifiers-America.com to discuss why their results differed from those at Consumer Reports. Representatives provided in-depth explanations of their methodology and described contrasting testing techniques. Air-Purifiers-America.com measures the air quality going into the unit, then again coming out of the unit. In this respect, the IQAir HealthPro Plus home air purifier captures the most particles in its collection filters in a single pass. At Air-Purifiers-America.com, air purifiers that capture the most allergens and produce the cleanest air get higher ratings. The IQAir HealthPro Plus uses several types of filters to capture allergens. Because a fan moves air through the filter, particle removal with the IQAir HealthPro Plus is dependent on the fan. On high speed, reviewers say the IQAir HealthPro Plus performs very well; the drawback is noise. On low speed, less air is pulled through the filters, so while the resulting air is still free from allergens larger than 0.3 microns, it takes longer to filter the air in the room. Air-Purifiers-America.com tests air cleaners on high speed with the IQAir HealthPro Plus performing best for allergen removal at the source as well as in the test room.

Consumer Reports uses a different approach, measuring particles in the test chamber before and after each air purifier is turned on for the same amount of time. Home air cleaners are tested on both high and low speeds. Because Consumer Reports measures total allergens in the chamber's air, the advantage is given to air purifiers that best reduce allergens in the entire room after a given time. Some models, like the Friedrich C-90B (*Est. $450), do this partly by reversing the electric charge in particles, so that allergens either fall to the floor or stick to the walls -- removing them from the air, but not necessarily capturing them on the air purifier's collection plates or filters. This testing technique can also penalize some air purifiers that don't process as much air on low speed as on high speed, like the IQAir HealthPro Plus.

Despite the differences in testing techniques and particle measurements, Consumer Reports' and Air-Purifiers-America.com's results, when considered together, provide a good foundation for determining the best air cleaners.

Reviews agree on the Ionic Breeze and Oreck XL

Although testing varies, and not all air purifiers are tested by each organization, Air-Purifiers-America.com and Consumer Reports do agree about one series of models -- the Ionic Breeze, which was sold by the now-defunct The Sharper Image. Negative publicity surrounding this electrostatic precipitator (meaning it electrically charges airborne particles) is believed to be at least in part to blame for The Sharper Image's demise.

The Ionic Breeze was given a poor rating by Consumer Reports, which claimed that the Ionic Breeze removed very few particles from the air in their tests. The Sharper Image complained about the testing method used by Consumer Reports, so the organization tested the Ionic Breeze a second time (after an independent expert reviewed and validated the testing method) and still got the same result. Consumer Reports tested the Ionic Breeze Quadra a third time for its May 2005 update, and yet again for another report. All of the Ionic Breeze air purifiers consistently achieved the same poor results.

The Sharper Image not only lost the lawsuit they filed against Consumer Reports for what they called false and malicious claims, but investors also mounted a class-action lawsuit against The Sharper Image, claiming fraud. In 2008, The Sharper Image filed for Chapter 11 bankruptcy and eventually closed all of its retail stores. The Sharper Image is expected to reemerge in 2009 as a licensed brand. According to a Jan. 18, 2009 story in The New York Times, the company is working on a new generation of air purifiers.

Testing results are also consistently poor for another high-profile, heavily advertised home air cleaner, the Oreck XL Tabletop Professional (*Est. $360). Like the Ionic Breeze, the Oreck did a poor job of removing allergens from the air. Like the Ionic Breeze, the Oreck XL charges particles and produces some ozone (the ozone smell gave one editor a headache during testing at Air-Purifiers-America.com.) A newer Oreck air purifier, the Oreck XL Tower Professional, did better in testing, but still lags far behind other air purifiers. At Air-Purifiers-America.com, the Oreck XL Tower removed 83 percent of airborne particles in the room, but only 25 percent at the unit, probably because of its electrostatic plates, which charge some particles and emit some ozone in the process. While the XL Tower represents a significant improvement over the XL Tabletop, that's not enough for the editors to recommend it in light of its ozone emissions and poor performance relative to other HEPA and combination air purifiers, most of which also cost less.