Everyone knows carpets are disgusting. What almost nobody explains clearly is that the method being used matters way more than the price, the logo on the van, or how confident the guy at the door sounds. Most cleaning jobs are sold on vibes. You’re told it’s a “deep clean,” it smells like a swimming pool for two days, and you assume that means something happened.
So here’s the actual comparison. Five real methods, what they do, who they’re good for, and the parts the sales pitch skips.
The Five Methods That Actually Exist
Strip away the marketing names and nearly everything on the market is one of these:
- Hot water extraction — the one everyone calls “steam cleaning”
- Encapsulation — polymer chemistry that traps dirt in crystals
- Dry compound cleaning — absorbent granules worked into the pile
- Bonnet / pad cleaning — a spinning absorbent pad on top of the carpet
- Shampoo and foam — the rotary-brush legacy method
That’s it. Everything else is a variation, a machine brand, or a sales word.
1. Hot Water Extraction (“Steam Cleaning”)
First thing: it’s not steam. Water is heated to somewhere around 180–220°F and sprayed into the carpet at pressure through a wand. It flashes into vapor on contact, which is where the name comes from. Then a vacuum slot immediately behind the spray pulls the water, suspended soil, and most of the chemistry back out.
Why it wins: it’s the only mainstream method that physically removes soil from the carpet rather than redistributing it or locking it in place. If your carpet is genuinely filthy — pets, kids, years of traffic lanes — this is the method that gets the deepest.
Why people hate it: dry time. Done badly, you’re looking at 12–24 hours of damp carpet, and damp carpet is when wicking happens. Wicking is when a stain you thought was gone climbs back up the fiber as the carpet dries, because moisture is wicking from the backing to the surface. Two days later you’ve got a ghost of the old stain and you’re furious.
The part nobody mentions: results depend almost entirely on the operator, not the machine. Water temperature, how many dry passes they run, how slow they move, and whether they bothered to pre-vacuum. A cheap job with a good tech beats a premium job with a lazy one every time.
2. Encapsulation
This is the method commercial spaces quietly run on. A cleaning solution is applied and agitated into the pile. As it dries, the polymers crystallize and basically freeze the dirt inside a brittle film. Later, normal vacuuming breaks the crystals up and pulls them out.
Pros: very fast dry time (often under an hour), minimal moisture, great for large open floor plans and low-pile commercial carpet.
Cons: it’s a maintenance method, not a rescue method. If the carpet is heavily soiled or has deep staining, encapsulation mostly just moves the problem around. It also depends on you actually vacuuming afterward. Most people don’t, and then they wonder why the carpet looks flat after a month.
3. Dry Compound Cleaning
Moistened absorbent granules — think sawdust with a cleaning agent — get spread across the carpet, worked in with a machine that brushes them through the pile, then vacuumed out along with whatever they grabbed.
Pros: almost no water. Nearly instant dry time. Genuinely safe for delicate natural fibers and for rugs you absolutely cannot get wet.
Cons: it only reaches the top portion of the pile. Deep-down grit and backing-level soil stay put. It’s also slow and labor-intensive, which is why it’s expensive per square foot.
4. Bonnet / Pad Cleaning
A rotary machine spins a soaked absorbent pad over the carpet surface. The pad picks up loosened soil. This is what you’re getting when a company brags about being “in and out in 20 minutes.”
Pros: cheap, fast, and fine for a light refresh before guests show up.
Cons: it cleans the top 10–20% of the pile and leaves the rest. Worse, using too much solution means sticky residue stays behind, and sticky residue attracts new dirt faster than clean fiber does. That’s the classic “it looked great for two weeks and then got dirtier than before” complaint.
5. Shampoo and Foam
The rotary-brush-and-detergent approach that dominated for decades. It lathers, it agitates, it looks impressive, and it’s largely been abandoned by anyone who cares about long-term results.
The problem: residue. Detergent left in the pile is a dirt magnet, and repeated shampooing builds up layers of it. This is one of the main reasons old carpets in old buildings get that crunchy, gray, perpetually-dirty feel no matter how often they’re cleaned.
Side-by-Side, Stripped Down
- Deepest clean: hot water extraction
- Fastest dry: dry compound, then encapsulation
- Cheapest per visit: bonnet cleaning
- Best for commercial maintenance: encapsulation
- Best for delicate rugs: dry compound
- Most likely to make things worse: foam shampoo with heavy residue
What Actually Determines the Result (Hint: Not the Method Name)
You can get a mediocre result from the best method and a great result from a mid-tier one. Four things decide the outcome:
- Pre-vacuuming. The majority of soil by weight is dry and can be removed with a vacuum before any liquid touches the carpet. Skipping this step means turning dry dirt into mud and pushing it deeper.
- Dwell time. Chemistry needs time to break down oils. A tech who sprays and instantly extracts is wasting your money.
- Agitation. Fiber needs to be physically worked for the solution to reach the soil.
- Extraction and drying. Whatever isn’t pulled out stays in. Air movers and a dehumidifier cut dry time dramatically, and almost nobody uses them on residential jobs.
The Quiet Workarounds People Use
Here’s the stuff that’s technically discouraged but extremely common.
- Renting a machine and running it properly. Rental extractors have lower heat and weaker lift than truck-mounted units. The trick is to go slow, run multiple dry passes, and set up fans. Do that and you close most of the gap for a fraction of the cost.
- Pre-treating yourself. Spot treatment and a pre-spray applied 10–15 minutes before cleaning does more for results than upgrading to a pricier package.
- Washing area rugs outdoors. For synthetic rugs, a hose, a mild detergent, a stiff broom, and a sunny day on a sloped surface gets results that would cost hundreds indoors. Wool is a different story — heat, agitation, and high pH can wreck it.
- Enzyme treatment for pet spots. Standard cleaning doesn’t remove urine salts from the backing. Enzymes do, but they need hours of contact time to work. Most services spray and move on.
- Choosing the method by fiber, not by price. Olefin and other heat-sensitive synthetics don’t love aggressive hot water. Wool doesn’t love high pH. Match the method to the material.
The Warranty Detail Nobody Reads
Many carpet warranties have conditions buried in the fine print requiring periodic professional hot water extraction on a set schedule. Skip it, and a manufacturer can deny a claim on a defect later. People find this out at the worst possible moment — after the carpet has already failed.
Bottom Line
If you want the honest cheat sheet: hot water extraction for real cleaning, encapsulation for keeping large commercial spaces presentable, dry compound for anything you can’t get wet, bonnet cleaning for a quick cosmetic refresh before company arrives, and foam shampoo basically never.
The method matters, but the person running it matters more. Ask what they’re using, ask if they pre-vacuum, and ask how they plan to dry it. The answers will tell you more than any price quote ever will.