Hot or Cold for carpet cleaning? What’s the Answer?

Do you wash your dishes in cold water, whether by hand or in an automatic dishwasher? Do you think it is more effective to wash your hands in cold water? Is it easier to melt away grease and oil on a soiled commercial kitchen floor using cold water?

If your answer to all of these questions is no, then I have one more question for you: Why would someone clean carpets with cold water? There is a very important reason heat—along with agitation, time, and chemical action—is one of the four fundamental components of cleaning, and that is heat speeds up the molecular activity of chemicals so they work harder. The process helps loosen and dissolve soils from carpets so that they can be more effectively removed. For the hotel housekeeper, more effective removal of carpet soils means an easier and more productive shift.

Studies reporting on the value of heat in cleaning date back to the late 1800s. Svante Arrhenius won the Nobel Prize for chemistry in 1903. One of his discoveries, which is referred to as the Arrhenius equation, is that heat increases chemical action. Essentially, Arrhenius found that for many common chemical reactions, the reaction rate doubles for every 10-degree Celsius increase in temperature over about 87 degrees Celsius.

While Arrhenius’s findings have been reevaluated and modified somewhat over the years and not everyone agrees with his conclusion that chemical reaction rates double for every 10 degrees Celsius, according to cleaning expert William Griffin, “I have yet to find anyone who thinks cold water cleans better than hot water or has any scientific proof that heat does not improve the cleaning process.”*

Further, some cleaning experts now suggest that even without chemical, cleaning effectiveness can be improved by using heat. “Even without soap, small amounts of grease will dissolve in water,” says Dr. Michael Berry, author of the landmark book on professional cleaning, Protecting the Built Environment: Cleaning for Health. “[But] the amount increases sometimes ten-fold in hot water.”**

In addition to enhancing cleaning effectiveness, when it comes to carpet cleaning specifically, heat, by way of hot-water carpet extractors, offers other benefits that can prove very helpful for hotel properties and their housekeeping staff. These include:

• Longer carpet life span. Soils in carpets behave like tiny daggers. With foot traffic, these soil daggers are pressed down and may be pushed from side to side. As this happens, they can actually cut carpet fibers. Over time such wear and tear can reduce the life span of the carpet. Hot-water carpet extractors can minimize this by more effectively removing embedded soils before they can damage the carpet.
• Easier removal of soils. Earlier we mentioned that heat can make the job of the housekeeper or carpet cleaning technician easier. Because heat improves cleaning effectiveness, fewer passes may be needed to remove soils from carpets. Spots, and in some cases, even stains, are easier to remove.*** The end result is improved worker productivity and faster cleaning.
• Improved appearance. According to Griffin, the use of hot-water carpet extractors often can improve the texture of the carpet once it dries. The carpet looks fuller and more luxurious.
• Faster drying times. Drying time is a big concern in hotel properties. The goal is to have a guest room clean and ready for occupancy as quickly as possible. The use of hot-water carpet extractors can facilitate this because moisture evaporates faster.

Clarifying Some Fine Points

Although it does appear that the use of hot-water carpet extractors can prove very beneficial for cleaning carpets in a hotel setting, and most cleaning experts will attest to this, some cleaning technicians still have questions. Among those are:

• How much heat should be used?
• What about energy consumption?
• Is heated cleaning really the best approach?

Helping us address these concerns is Doyle Bloss, who has been involved in the professional carpet cleaning industry most of his life and now serves as marketing manager for U.S. Products, manufacturers of professional portable carpet extractors.

To begin, a common question asked by carpet cleaning technicians is that if approximately 100 degrees Celsius is a recommended temperature of water when using a portable hot-water extractor, is hotter better? According to Bloss, “In general, you want to maximize heat. There are few cases when you want to turn down the heat.” He does suggest that one exception would be when cleaning wool carpet. For wool, he recommends about 71 degrees Celsius to avoid damaging the fibers.

Another concern that comes up when discussing hot-water carpet extraction is that heating the water/solution demands more energy consumption, making it a less sustainable way to clean carpets. However, Bloss, as well as other carpet cleaning technicians, believes there are several ways to address this issue. Does the use of a portable heated carpet extractor use more energy than a cold-water extractor? In many cases, the answer is yes. Can cleaning a carpet using a hot-water carpet extractor reduce cleaning passes and expedite the cleaning process? Once again, in many cases the answer is yes. “Essentially, we have a trade-off on this issue,” says Bloss. “While the hot water [extractor] may require more energy, if the carpets are cleaned faster by using it, this amount may be negligible and, in fact, it may actually save energy.”

Going a step further, some in the carpet cleaning industry suggest that the use of hot-water carpet extraction may even be a “greener” way to clean carpets. They have come to this conclusion because it can mean less chemical is needed to satisfactorily clean the carpets. Whenever less chemical is required in cleaning, the impact of cleaning on the environment is reduced, which is the ultimate goal of green cleaning.

Putting Heat to the Test

The vice president of a leading Canadian cleaning chemical manufacturer advises his distributors to let their customers compare his company’s products with the products the customers are using now. He refers to this as the “cleaning challenge,” and, invariably, he is happy to report that most customers do find his company’s cleaning chemicals superior.

While it may not be as easy to compare a cold-water carpet extractor with a hot-water machine, many distributors will allow customers to “test-drive” a machine before selecting it. If your hotel property is unsure about the value of heat when cleaning carpets, taking this cleaning challenge may prove beneficial. Try a portable hot-water carpet extractor and put it to the test. As they say, the proof is in the pudding…and know that our famed chemist, Svante Arrhenius, will anxiously be awaiting your results.

Grant Hickey is with Advanced Specialized Equipment in Sydney, Australia, a distributor of U.S. Products hot-water carpet extractors.  He can be reached thru the company Web site at www.usproducts.com

this article was published in Executive Housekeeper magazine June 2014

* Willliam R. Griffin is the president of Cleaning Consultant Services, Inc., Seattle, Washington (US).

** Protecting the Built Environment: Cleaning for Health, Raleigh, NC: Tricomm-21st Press, 1994. *** Unlike a spot, a stain is typically more permanent because it can discolor carpet fibers. However, treatments are available for removing many carpet stains.