A recent study by Airmid Healthgoup, a Dublin, Ireland-based research organization, reports that carpet and upholstery cleaning with truck-mounted equipment improves indoor air quality and reduces allergens with regularly scheduled professional cleaning.
"To maintain the healthiest environment for occupants, we recommend hot water extraction cleaning two to three times per year and vacuuming at regular intervals.”—Dr. Bruce Mitchell, CEO, Airmid Healthgroup.
Airmid teamed up with Stanley Steemer, a Dublin, Ohio-based company to help with the research. Stanley Steemer of course uses the hot-water extraction method as their primary cleaning process.
The study’s main focus was to find ways to improve indoor air quality.
“Our goal at Airmid is to identify and evaluate situations where indoor air quality is a concern, and then work with corporate household names to provide the best possible solution, through contract research and technology transfer,” said Dr. Mitchell.
How they did it
The study took place in 20 U.S. homes in February 2013. Surface and air samples were taken before and after cleaning. The results seem to be very impressive: up to 97 percent reduction in allergens in carpet and 96 percent reduction in soft furnishings.
From the graphs, which can be seen here, you'll notice a spike in airborne mold during the cleaning by what appears to be about 30-40 percent, but just one hour after the cleaning the levels drop dramatically and fall well below the original airborne mold count. There are also graphs displayed showing dog and cat allergen removal.
"Surface levels of dust mite allergens on carpets, for example, were reduced by 91 percent, of cat allergen by 95 percent, and of dog allergen by 97 percent. The cleaning process also resulted in a marked reduction in airborne cat allergen exposure,"
If carpet has contaminants, why don't I just get hardwood floors?
That's exactly what the Swedish government thought in the 1970s. During that period they reduced carpet in buildings by 70 percent, but years later studies revealed that allergies had increased 30 percent simultaneously. A fifteen-year study of this confirmed that, yes, carpet and soft furnishings contain allergens and other contaminants, but they were more easily removed from carpet, as opposed to hard surfaces, with regularly scheduled cleaning.
We tried finding the source of the study on the Swedish Statistics website but none existed. There are, however, several reputable websites that refer to the study, two of which can be found below:
Simply put, carpet acts as a large filter in a home, catching all these contaminants we are sensitive to. And with hot-water extraction, they can efficiently be removed, creating a healthier home and working environment.
Can we trust this study?
I do think it's notable that the study was sponsored and paid for by Stanley Steemer, which coincidentally uses hot-water extraction as their primary carpet cleaning system.
It would be nice to see a larger case study involving more than twenty U.S. homes. We also don't know anything about the homes – whether the residents suffered from allergies, the geographic location of the homes, or if they had pets or kids. We also aren’t told the last time the carpets had been professionally cleaned.
We'd also like to see other cleaning methods in the study. This was an obvious attempt to tout hot-water extraction (which we agree is the best system), but there are many other methods by which to clean carpet, and many recent advancements in chemistry.