Steam Cleaning vs. Low Moisture Carpet Cleaning

So which is better? Hot water extraction (a.k.a “Steam Cleaning”) or low moisture cleaning (a.k.a “Dry Carpet Cleaning”). Advocates of hot water extraction will argue that steam cleaning is the only method that deep cleans the carpet. Proponents of dry carpet cleaning will argue that hot water extraction saturates the carpet, pad (and even subfloor) with water which can lead to shrinkage and mold growth. They will also argue that hot water extraction leaves detergent residue in the carpet fibers causing the carpet to attract dirt and re-soil at a rapid rate.

In the old days, carpet cleaning professionals either steam cleaned or shampooed carpet. The top two post-cleaning complaints from customers 40 years ago were “My carpet was wet for days” and “My carpet is dirtier now than before it was cleaned”. Fast forward to present day. According to a national survey, the top two complaints from customers after having their carpet steam cleaned are “Dry time is too long” and “It looked good when they left but the spots came back”.

Steam Cleaning / Hot Water Extraction Process

The steam cleaning or hot water extraction process begins with the application of a high alkaline pre-spray. Hot water and additional chemicals are then injected into the carpet at 300 – 400 psi., saturating the carpet, pad and sometimes subfloor. The dirty water and chemicals are then vacuumed out of the carpet.

So what is the problem with Steam Cleaning?

On average, only 70% of the dirty water and chemicals are recovered from the carpet using hot water extraction. This means that the remaining 30% of the moisture you feel under your feet is chemical filled, dirty water (Still want to let your baby crawl on the carpet?) As the carpet dries, residual soil can rise to the top of the fibers causing the original and even new spots to surface. This issue, known as “wicking” is especially common in highly soiled environments. Another problem is the excess moisture in the carpet and pad can cause shrinkage of the carpet backing, mold and odor problems. This can lead to health issues and permanent damage to the carpet and subfloor. Finally, the sticky detergent residue left in the carpet fibers, if not returned to a pH neutral state, will attract dirt and cause a rapid re-soiling of the carpet.

Hot water extraction is not an eco-friendly process. First, the large machines used burn excess fuel and emit toxic exhaust fumes outside your home. Second, the average job uses over 75 gallons of fresh water to complete. Finally, there are few approved dump sites for carpet cleaners. Chemical filled waste water is often dumped into nature areas, streets or storm water drains to the detriment of the environment and city water supply.

Dry Carpet Cleaning Process

The dry carpet cleaning, or encapsulation process, begins with the extraction of dry soil, dust mites and allergens using a HEPA filtrated commercial vacuum. High traffic and heavily soiled areas are then pre-treated with an encapsulating pre-spray designed to assist in the release of contaminants from the carpet fibers. A low moisture encapsulation product is then applied to the carpet and agitated into the carpet fibers using a counter rotating brush (CRB) machine. The machine is able to deep clean the carpet fibers without the risk of damaging the carpet backing or pad. Depending on the encapsulation product used, the contaminated soil either quickly dries into a crystalline form or is absorbed into an organic, sponge-like compound. The carpet is then vacuumed again to remove the encapsulated soil.

The Advantages of Dry Carpet Cleaning

The carpet is dry before the technician leaves the home and can be walked on immediately. There is no detergent residue left in the carpet fibers and the encapsulation process is designed to eliminate wicking and resist re-soiling. Dry carpet cleaning is organic, eco-friendly and safe for children and pets. The process uses minimal amounts of fresh water and there is virtually no waste discharge. The encapsulated soil can be disposed of in any trash receptacle.

Which process is best?

The short answer is it depends on the condition of the carpet. In cases of flooding, extreme pet urine contamination or sewage overflow, hot water extraction is the recommended process. For all routine cases, the dry carpet cleaning process is the best choice.

Written by Rich Reagan, IICRC Certified Technician and former Hot Water Extraction advocate.