When it comes to carpet cleaning, there are plenty of choices, including soap-free options.
Confused about carpet cleaner? There are plenty of options when it comes to choosing a carpet cleaning solution or soap, so you'll want to talk to your carpet cleaner about the best options for your floor.
Can carpet cleaning leave residue behind?
In response to concerns about the effects of soaps used in the carpet-cleaning process, many carpet cleaners now offer soap-free or no residue-cleaning services.
Some homeowners are wary of the hot-water extraction or steam carpet cleaning methods. This is a carry over from the old days when the principal cleaning agent used in this process was high-alkaline soap derived from natural plant or animal fats and oils.
This soap was usually made from the reaction of sodium hydroxide or lye with the fatty stearic acids in a process known as saponification. The resultant detergent was very effective in the removal of all kinds of soils, but was very caustic and had a very high pH value.
To ensure proper cleaning, the residues from the cleaning process would have to be thoroughly neutralized and extracted or they would become a virtual soil magnet that would only attract more dirt when dried.
It's an old myth that it is better to wait as long as possible before cleaning your carpet, and that carpets will get dirtier much more rapidly after cleaning.
How does carpet cleaning work?
Let's look at the chemistry of carpet cleaning and the developments in the production of detergents in recent times.
Carpet cleaning is the process by which soil is removed from the fabric, either mechanically or by the use of solvents or emulsifiers. Some soils are soluble in aqueous or organic solvents and are relatively easy to remove, while other types become trapped in tars and oils and get permanently embedded unto the carpet fibers.
You might hear that all you need is specially treated water or steam to get your carpet clean. This will work if the carpet is not heavily soiled or stained, but for situations where the fabric is heavily contaminated, that will not suffice.
Carpet cleaning is accomplished when the soil is sequestered from the carpet fibers by the action of a wetting agent and transformed into a solution, emulsion or suspension that can then be flushed out.
This is a complex process, but for simplicity, consider water-soluble soiling. Water is a good wetting agent, but its action is limited by surface tension, which has to be reduced in order to get it close enough to the soil particles. That is what the soap does.
How to choose a carpet-cleaning soap?
Today, carpet cleaning soaps and detergents are made from synthetic materials. There is wide variety of chemical formulations and available.
These days, carpet cleaning products not only have cleaning properties, but also may have accelerants, builders, carpet deodorizer and fluorescent dyes included.
As a result, their effects vary widely and they are no longer called soaps. In reality, they are surfactants, or surface acting reagents, and vary widely in properties.
The most aggressive surfactants are quite similar in effect to the old type soaps, and therein lies the problem. They are high in alkalinity and must be neutralized after cleaning or they will leave a soapy residue that will attract soils when dry.
A good carpet cleaning professional will be thoroughly familiar with different types of cleaning agents and will be able to determine the best type of soap-free reagent to use in your particular situation.
Editor's note: This is an updated version of an article that was originally posted on July 15, 2013.
About this Angie’s List Expert: Victor Nugent is the owner and president of AJS Carpet Cleaning, Inc., providing carpet cleaning services in Salt Lake City. For more than 11 years, AJS has provided carpet cleaning, upholstery cleaning and tile and grout cleaning services and is a recipient of the 2012 Angie’s List Super Service Award.
As of Jan. 7, 2016, this service provider was highly rated on Angie's List. Ratings are subject to change based on consumer feedback, so check Angie's List for the most up-to-date reviews. The views expressed by this author do not necessarily reflect those of Angie's List.