Although there is an actual steam cleaning industrial process, in the context of carpet cleaning, "steam cleaning" is often mistaken for hot water soil extraction cleaning, which is professionally known as HWE. The hot water soil extraction cleaning method uses equipment that sprays heated water and detergent on the carpet and simultaneously, the water and detergent is extracted, along with any dislodged and dissolved dirt. Many carpet manufacturers recommend professional hot water extraction as the most effective carpet cleaning method which also provides a deeper clean.  Actual steam could damage man-made carpet fibers and change the characteristics as they are usually set using heat. Woven carpets can shrink but most carpets are not woven and are in fact tuffed on a laminate backing, velvet-piled carpets and Berber carpets may become fuzzy which is known as pile burst.  Most problems can be avoided by professional experienced cleaners.
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