Steam cleaning versus dry carpet cleaning
Four methods, one question: does it take the dirt out of the building, or move it around inside the carpet?
Hot water extraction, usually called steam cleaning, is the only common carpet cleaning method that flushes soil out of the carpet and removes it from the building. Dry methods (encapsulation, bonnet cleaning and dry compound) suspend or absorb surface soil and rely on later vacuuming to remove it. Dry methods dry fast and suit interim commercial maintenance. Hot water extraction is the method carpet manufacturers such as Shaw Floors name for periodic deep cleaning. DeepSteam.ca uses truck-mounted hot water extraction.
The four methods, plainly
| Method | How it works | Soil removal | Drying | Best use |
|---|---|---|---|---|
| Hot water extraction (steam cleaning) | Pre-spray, then hot water rinsed through the pile under pressure and vacuumed straight back out. | Deepest. Soil leaves in the waste tank. | Hours with a truck-mount; a day or more with a portable. | Periodic deep cleaning of homes and businesses; the method warranties name. |
| Encapsulation | A polymer solution is brushed in; it dries around soil particles into brittle crystals, vacuumed away over following days. | Surface and upper pile. Depends on later vacuuming. | Under an hour. | Interim maintenance of commercial carpet between extractions. |
| Bonnet cleaning | A rotary machine spins an absorbent pad over pre-sprayed carpet. | Top of the pile only. Can push soil and residue downward. | Fast. | Quick cosmetic clean of commercial low pile. Not recommended for residential cut pile. |
| Dry compound | Moistened absorbent granules are brushed through the pile and vacuumed out. | Light to moderate. Granules can remain in dense pile. | Immediate. | Areas that cannot get wet; natural fibre rugs in some cases. |
Is "steam cleaning" actually steam?
No. The working fluid is hot water, sprayed into the carpet and recovered by vacuum. The visible steam is water flashing off in room air because it is hot. True steam vapour has little cleaning value on carpet; it cannot carry soil away. The name stuck decades ago and everyone, including this site, still uses it. The technical term is hot water extraction, and the industry standard that describes the methods is the IICRC S100 Standard for Professional Cleaning of Textile Floor Coverings, seventh edition, 2021, published by the Institute of Inspection, Cleaning and Restoration Certification.
What do the manufacturers say?
Shaw Floors' care guidance names the method directly: "Schedule a professional hot water extraction (steam cleaning) anywhere from 6-18 months, depending on traffic." The Carpet and Rug Institute recommends professional deep cleaning every 12 to 18 months and running a Seal of Approval certified cleaning, which tests equipment and products for soil removal, resoiling and pH. Check your own carpet's warranty, which may specify the method and interval required to keep coverage.
When does a dry method make sense?
- Commercial carpet between deep cleans. An office that gets extraction annually can hold its appearance with encapsulation every few months. It is fast, the floor is open within the hour, and it stretches the interval between deep cleans.
- Carpet that must not get wet. Some natural fibre rugs, glued-down carpet over a floor that cannot take moisture, or a space that cannot be closed long enough to dry.
- Appearance touch-ups before an event. A bonnet pass makes a lobby look better tonight. It is not a clean.
The mistake is using a dry method as the only method for years. Soil that is never extracted builds up in the base of the pile, residue from repeated encapsulation and bonnet chemistry accumulates with it, and eventually the carpet looks grey no matter what is done to the surface. Hot water extraction at that point recovers a startling amount of soil and the carpet's colour comes back. The office carpet tile photographs on the commercial cleaning page are that exact situation.
Portable versus truck-mounted extraction
Within hot water extraction there is a second choice: a portable machine that plugs in, or a truck-mounted unit that runs from the van. Both use the same principle. The truck-mount heats water hotter, pulls a much stronger vacuum, and leaves the carpet drier, which is why DeepSteam.ca uses it exclusively. The full comparison is on the truck-mounted steam cleaning page.
More guides: how often to clean carpets, carpet drying time, pet urine in carpet.