Those companies that claim to give you good pricing are limited on the result they can give you cause of the minimal investment they make on machinery and chemical products. Most of the time, they try cleaning your carpet with a grocery store rental electric machine that has many limitations and over the counter chemicals that are not strong enough to be effective on eyesore stains because they are over the counter.
There are several reasons, many times these companies clean the surface of the spot leaving a large percentage of it deep in the carpet, sometimes they manage to remove the spot but cannot remove because of the soap/chemical they used and you get a residual spot. The most common reason is the vacuum limitations, there electric machine cannot extract/vacuum effectively.
The main reason is the heat/steam that we use, works alongside heat activating industrial biodegradable preconditioners and pre spotters. These chemicals are not over the counter and only are effective if you have high heat alongside rising capabilities that out the industrial gas powered machine has.
Even though the weather can affect drying time with Real Steam Carpet Cleaning. There is not much of a time difference due to the temperature of the water and the high vacuum capabilities. On the other hand using other methods can increase time durations by days. Therefore be careful to whom you let touch your carpets. Steam carpet cleaning has proved as the best and effective carpet cleaning and called as deep cleaning. This method is consider as the topmost efficient way of cleaning because it cleans 95% of the dust from the carpet. It has stated that it is the only way to clean deep tough stains on the lower layer of the carpet to clean it properly.