Should the health claims of UV vacuums be called on the carpet?

Manufacturers often post links on their websites to studies that they claim prove how well their products work. But one study, published in the journal Environmental Science & Technology, doesn't make the intended case for the germ-killing capability of a vacuum cleaner equipped with an ultraviolet germicidal lamp, or UVC.

The study, by researchers at Ohio State University, began with funding from Halo Technologies, maker of the Halo UVX upright vacuum. Halo sold its technology to Oreck in 2008, but not before the company's advertising caught the eye of the Federal Trade Commission, which was concerned about Halo's claims regarding the vacuum's advertised health benefits. Oreck currently sells its UV-equipped upright, the $600 Oreck Halo, through phone orders and some Oreck stores.
 
According to senior author Timothy Buckley, an associate professor of environmental health sciences at Ohio State, the study compared the vacuum's ability to reduce colony-forming units (CFUs) of surface microbes—that is, microbes healthy enough to reproduce—in three different settings, including a home's family room. On areas of carpet divided into three-square-foot sections, the researchers tried the Halo three different ways: with the vacuum alone (and brush roll on), with the UV lamp alone (an option not available to consumers), and with the vacuum and UV powered on.
 
In comparing reductions of CFUs before and after running the vacuum each way, the researchers saw an average 78 percent decrease in CFUs without the UV, 60 percent with the UV alone, and 87 percent with the vacuum and UV together. While the UV's contribution appears significant, the study also reveals that each treatment began with differing sample sizes—an issue, said Buckley, that arose during peer review. Treatment with the vacuum and UV, for instance, began with an average 76 percent more microbes than that with the vacuum with a beater bar alone (and no UV). Another way to look at the results is that the average levels of CFUs remaining after running the vacuum with and without UV were, in fact, identical.

In several of the many instances the researchers ran their tests, use of the UV alone or with the vacuum running resulted in reductions of CFUs to zero—a testament to UVC's proven benefit given sufficient exposure time. On average, however, UV's contribution to a healthy home is less clear. Another variable not accounted for in the study is to what degree the vacuum might have resuspended surface particles, including microbes. "I would love to repeat this and take into account the airborne," said Buckley.
 
Consumer Reports has tested both the Halo UVX (now discontinued) and Oreck Halo upright, both of which use ultraviolet-C radiation. We operated under the premise that a vacuum need not kill pests as long as it removes them from the home. So we tested them the same way we do other vacuums—chiefly for how well they clean floors without emitting back out what they draw in.
 
As with the Halo UVX, we judged the Oreck Halo good for deep-cleaning carpets, two notches lower than the best-carpet cleaning uprights. (For cleaning bare floors and keeping emissions low, it scored excellent.) Both vacuums scored only good for picking up pet hair, the dander in which can trigger allergic reactions.

The bottom line? While the study appears to have found potential benefit in a vacuum that bolsters its basic function with UV-C radiation, we've tested many upright vacuums that clean floors consistently better than either UV-equipped model. And they often did so for less than half the price.
 
—Ed Perratore

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