The main options for professional cleaning a carpet is steam cleaning. Steam cleaning, contrary to its name, uses hot water. Actual steam would only damage the carpet. It gets the best results for all types of carpet cleaning. Also called Hot Water Extraction (HWE), steam cleaning works by firing jets of hot water at the carpet that are vacuumed up at the same time. The result is the dirt is dislodged from the carpet with no or only minimal chemicals needed.
By contrast furniture upholstery can be the hardest to clean. It is difficult to reach all the various nooks and crannies. Even more, furniture tends to accumulate more dirt in the first place. This is especially true of couches, or other seats people tend to snack on. Many types of upholstery are more delicate than carpets and rugs, since they are designed to be comfortable to sit on.