The experiment conducted at CNET’s product-testing laboratory in Louisville, Kentucky, involved using a reflectometer and basic physics principles to assess the cleaning efficiency of different carpet cleaning machines. Color was discussed in terms of visible light wavelengths and how our brains interpret different colors. The reflectometer was used to measure the “color” of a white carpet before and after staining it with common substances like red wine, coffee, motor oil, and marinara sauce to evaluate how well each machine cleaned the stains. The ratio of reflectivity values before and after cleaning was used to assess performance.
The reflectometer used in the experiment had a search unit with a tungsten bulb that emitted light and measured the reflection on the surface of the carpet sample. The whiteness index was utilized to quantify how “white” a sample was by measuring reflectance under different light filters. Stained carpet squares were prepared with various substances, and cleaning cycles were performed using each machine. Reflectivity values were measured before and after cleaning to determine how efficiently the machines restored the carpet to its original white state.
In addition to assessing general cleaning efficiency, a tough mess test was conducted specifically for marinara sauce stains, which proved to be the most challenging to remove. Each machine was set to its maximum or tough mess setting, and additional cleaning steps were performed based on manufacturers’ recommendations. The reflectometer measurements were adjusted for comparison in the tough mess test to evaluate the machines’ performance in dealing with stubborn stains.
The results of the experiment were summarized in a table, with higher scores indicating better cleaning performance. Some carpet cleaning machines, such as the Bissell Hydrosteam Pet Model 3423 and the Hoover Pro Clean Pet Carpet Washer, did not perform well in the tests, receiving low scores for cleaning efficiency. On the other hand, machines like the Bissell ProHeat 2X Revolution Pet Pro Model 3587 showed better results in the tough mess test, achieving higher scores despite not ranking as high in other categories. The Bissell Crosswave Hydrosteam All-In-One Multi-Surface Cleaner was the lowest performer overall, struggling to clean effectively in both tests.
Overall, the experiment involved rigorous testing of carpet cleaning machines using a methodical approach and scientific principles to determine their performance in removing stains. The reflectometer was a key tool in quantifying the cleaning efficiency of each machine, providing valuable insights for consumers looking to make informed purchase decisions. The results highlighted differences in performance among the tested models, with some machines excelling in certain areas while others fell short in terms of stain removal capabilities.
