Do-it-Yourself... Although they are handy for emergency spills, Rug Doctor rental units, Bissel, Hoover, Electrolux, Kirby, and all other cleaning units available for purchase to the general public can't even come close to our cleaning power. The large majority of these units rely on hot tap water. In most homes this is about 120 degrees. That of course is the starting temperature. Every minute the water sits in your machine's tank, the lower the solution temperature drops. This heat transfer occurs very quickly. It is entirely possible that by the time the solution hits your carpet, the hot water you started with is now only room temperature. This is not very effective for carpet cleaning. Remember higher heat cleans better. Even worse, some of these types of machines use shampoo-type foam cleaning. These types of cleaners cause your carpet to resoil and "ugly-out" very, very quickly. Not only are you leaving all of the foam from the shampoo detergent in your carpet, but all the dirt remains as well. It just doesn't magically disappear as some manufacturers would like you to believe. Shampoo-based cleaning agents are trouble for most residential carpets.