A number of years ago, I was introduced to the idea of low moisture encapsulation (encap) for carpet.

Having only been exposed to hot water extraction cleaning, the idea that a product could be scrubbed into the carpet without immediate extraction seemed foreign, but the pictures and testimonials from cleaners I trusted gave me enough faith to buy a counter-rotating scrubbing machine.

Since that time, I’ve been trying to get my head around how it works and when to use and not use it. After numerous debates, discussions and trial and error testing, these are my findings.

Whether we formally recognize the process of agitation, we all have an innate understanding of its importance in cleaning. You can observe an 18-month-old child scrubbing dirt off their hands — even a child understands agitation!

In the HWE process, quite typically (but certainly not always), the agitation process is often neglected. In HWE, a pre-spray detergent is applied to the carpet, left for a time to dwell and rinsed/extracted with hot water and a wand. Conversely, the low moisture encapsulation process includes applying an encapsulating detergent to the carpet, followed by intense machine assisted agitation. The solution is usually cold, and in its purest form, there is no immediate extraction process.

In recent years, some carpet cleaners have switched completely to encap. Others, like myself, have added encap to our repertoire. The difficult questions to get answered are: 1) how does encap work; and 2) how do I decide whether to encap or use HWE?

How does it work?

Although there are variations in how encap is carried out, a typical scenario involves a specially formulated encap detergent that is run through a solution tank on a scrubbing machine and scrubbed into the carpet.

ED-Mathot-1To the uninitiated the results can be outstanding (see pictures). The encap solution emulsifies the fats, oils and starches that typically bind soil to carpet fiber through the scrubbing action.

The solution forms micelles, which uniformly distribute the fats/oils through the wetted carpet fiber, and as a result, the soil also is distributed more evenly (as opposed to the soil being on the top visible portion of the pile). To give an instantly clean look, many of these products use crushed silica, which gives the carpet an instant brightness.

However, the secret weapon in the encap solution is the crystallizing polymers. The crystallization, which starts as soon as the moisture is deployed and exposed to air, also reflects light in a way that makes a carpet look brighter and cleaner. The crystals eventually dry out, encapsulating the soil captured by the detergent. The dried out crystals, which hold the soil, are removed through various vacuuming cycles.

Armed with this information, let’s examine when encap is useful.

Deciding between encap and HWE

Low moisture encapsulation really has been brought into the spotlight in the last 10 years in commercial carpet cleaning, although the technology is many decades older.

Compared to HWE, the process requires far less training, lower equipment costs, and lower running expenses and maintenance, and production rates are typically higher than HWE. This has allowed savvy cleaners to be more competitive and cost savings to be passed on to the customer.

Other advantages include much faster drying carpet that can be put back into service sooner, less security concerns (no hoses running through partially opened doors) and often much cleaner looking carpet.

So why aren’t we encapping every carpet? While encap has revolutionized modern carpet cleaning, it certainly has a time and place — and it’s not on every carpet.

Recently I had with a new account — a Chinese restaurant. After a thorough pre-vacuuming of the carpet, I ambitiously attempted to encap it. My trial area was at the transition zone from the tiled kitchen to the carpeted restaurant.

A few passes of the scrubbing machine made minimal difference to the appearance of the carpet, so I had to go to plan B: Hot water extraction. Typically, encap detergents rely on the agitation portion of the (TACT) cleaning pie. The chemistry is typically mild in pH, and pH plays an important role in breaking down fats and oils. In this situation at the Chinese restaurant, I had to bring out the high-pH, solvent-boosted big guns and flush the carpet.

In addition to this, encap is partly a soil redistribution system, so if the carpet is soil saturated, the only thing that will make it look clean is the removal of said soil.

I also had an encap failure recently on a residential carpet. The customer requested low moisture cleaning, and after inspecting the carpet I was skeptical that encap would be sufficient. My suspicions were confirmed when the traffic lanes, although vastly improved, required HWE to look respectable.

I essentially used both the encap and HWE process to clean this carpet. I also often find that after cleaning large areas of carpet with encap, there are usually some areas that simply don’t respond and require the chemical versatility and flushing power of HWE.


Having said the above, note that I have also had HWE failures for which encap has been the savior. I recently returned to a vacated property cleaned by a competitor at the request of the property manager (for whom I do a lot of work).

The synthetic Berber carpet had been steam cleaned, and the outline of a rug was evident in the living area. A quick five-minute encap had that carpet looking perfect. HWE here had been carried out without agitation, and the volumes of water used on the hydrophobic carpet had most likely facilitated some wicking.

I have found that on light to moderately soiled synthetic residential carpet encap delivers the best results for the effort and time required. In situations where I decide to steam clean, I’ll often bring encap out to tidy up and finish off the traffic lanes. Encap has a remarkable ability to even out the appearance of a non-uniform or streaky steam clean.


Phil Mathot is a second generation carpet cleaner and has the owner/operator of a carpet cleaning business in the western suburbs of Sydney, Australia for the last five years. Mathot is a certified WoolSafe fibre specialist and enjoys the technical aspects and challenges of carpet and upholstery cleaning. Apart from his own blog, which gathers interest from the general public seeking answers to various carpet and carpet cleaning related issues, he also has written several articles for Australia’s INCLEAN publication.