Carpet Cleaning with Robots: What Runs Autonomously — and What Stays Manual

The process is always the same: a rotating brush loosens material from the pile, a blower pulls it through a filter into a bag or container, and the area is usable again the moment the machine has passed. No water, no drying time, no risk of over-wetting a textile covering. Every machine we run on carpet is a dry machine — and that holds even for the one machine in our fleet that carries water. The CC1 is a scrubber-dryer, but one of its four official modes is carpet vacuuming, dry, and Pudu states plainly that carpet cleaning requires the carpet vacuum attachment, which is sold separately. Even the wet machine goes dry on carpet.

That draws the line for what you may promise. Loose soil comes out: dust, sand, crumbs, hair, fibres, the material a corridor accumulates every day. Anything bonded to the fibres stays: spilled drinks, grease marks in front of the coffee point, de-icing salt streaks in winter, stains of every kind. Removing those is wet work — spot treatment and, at longer intervals, deep extraction or shampooing of the whole area. No robot in this class does either, and stating that up front is worth more than any specification: cleaning contracts that promise "carpet cleaning" and deliver vacuuming create conflict at the first stain.

It is also worth calibrating what a properly vacuumed carpet looks like. An observation from our own deployments, explicitly as an observation and not a specification: a rotating brush lays the pile in the direction of travel and leaves visible lanes. Those nap lines are the sign the floor was worked, not a defect, and foot traffic evens them out over the course of a day. In representative areas — hotel lobbies, executive floors, showrooms — it pays to plan the direction of travel deliberately: straight, parallel lanes read as cared-for, a crossed pattern reads as random.

The Whiz is the machine of the three for which the manufacturer names carpet first: SoftBank Robotics writes in its own launch release, "It works best on carpets and hard flooring." The data sheet rates it at 465–557 m²/h with three hours of runtime per charge, and the launch release states up to 1,500 m² per charge — which is what those three hours of running produce at that area rate. The four hours quoted alongside it are the charging time, not a runtime; do not add them to the working window. The brush is officially described as a removable rotating brush with automatic height adjustment, filtration is HEPA capturing 99.97 % of PM2.5 particles including pollen and dust, the dust bag holds 4.0 litres, and normal mode is stated at 62 dB. Two things belong in the plan: at 30 kg plus a 5 kg battery this is not a machine anyone carries up a floor on the side, and both the battery swap and the start are manual — Whiz Connect monitors, it does not launch cleaning runs. The full machine-versus-machine comparison sits in our vacuum robot comparison.

The MT1 Vac is officially not a carpet-only machine but a three-in-one for carpet and hard floors: vacuuming at 55 cm width, sweeping at 70 cm with side brushes, dust mopping. Rated at a maximum of 1,400 m²/h, it carries the largest waste capacity in this group — 20 litres as a 6-litre trash box plus two 7-litre disposable bags, which Pudu translates into up to ten consecutive days in a 1,000 m² carpeted area before emptying. Filtration is HEPA H11 as standard, capturing over 98 % of particles down to 0.3 µm, with H13 optional at 99.97 %; that documents a filter class, not a health outcome, and we do not claim more. Its floor adaptation is real and officially described — AI-supported floor recognition identifies carpet and hard floor in real time and adjusts brush pressure, roller speed and suction accordingly — but it is not the pile-measuring brush height adjustment that circulates in many descriptions of this machine. Two honest gaps: the official runtime is 3–6.5 hours with exactly one mode specified (4 hours, standard sweep-and-vacuum, on hard floors), so there is no official carpet runtime and therefore no serious area calculation for carpet; and Pudu publishes no noise figure at all for this machine. We plan it as a loud machine. The machine profile is in its own article.

The NR 1700 is the small, camera-free one: 280 mm cleaning width, maximum 0.3 m/s, a washable HEPA H13 filter with 530 cm² of filter area, a 1.4-litre dust container. It is also the only machine in this group whose manufacturer publishes a pile limit — and it is a tight one. The operating manual restricts use to carpets with a free fibre length of up to 15 mm, advises fencing off high-pile carpet with magnetic strips or no-go zones in the Nexaro HUB, and gives two reasons: on high-pile carpet the wheels can spin and disturb navigation, and dark, dense carpets can be read as a cliff by soiled drop sensors. Its data sheet holds a detail worth knowing for carpet planning: the noise values — Eco 49 dB(A), Balanced and Performance 57 dB(A) each — carry the footnote "measured on carpet", while the runtimes of 250, 110 and 105 minutes carry the footnote "measured on hard floor". The two headline figures were measured on different surfaces, so the runtime is not a carpet figure. The 100 m²/h cleaning rate carries its own footnote about floor plan, furnishing, floor covering and soiling; in our deployments the effective rate is 50–75 m²/h and one charge covers 200–300 m², which we document in the field report.

One comparison across all three is worth making explicitly, because it decides more installations than any performance figure: only Nexaro publishes a pile height. Pudu specifies short-pile carpet for the CC1 and its separate carpet attachment; for the MT1 Vac and for the Whiz, neither Pudu nor SoftBank Robotics publishes any pile specification at all. Which is why there is no honest percentage of "suitable" carpets, and why we inspect the covering on site before installation rather than quoting one.

In practice the question is almost never "which is the best carpet robot". It is: what does the hard-floor-to-carpet split look like on each floor, and are the carpet areas contiguous? A carpet-dominated floor — a hotel guest floor with corridors, an office floor laid with carpet tiles — is a clean case: one vacuum covers it. A genuinely mixed floor gives you two routes. Either one machine that officially handles both surfaces, which is what the MT1 Vac is built for as a carpet-and-hard-floor machine with floor recognition, and what SoftBank means when it puts carpets and hard flooring in the same sentence for the Whiz. Or a pair of machines with clearly separated jobs.

The pair becomes the honest answer as soon as the hard-floor part needs wet cleaning. Entrances, sanitary areas, canteens, tiled circulation zones: what is bonded to those floors comes off with water and mechanical action, and no vacuum solves it — a scrubber-dryer does, and it never touches carpet wet. Which machine that is, and for which area, is what our scrubber-dryer guide works through. The CC1 is the interesting borderline case here, because it can do both — but not in one pass. Carpet vacuuming means fitting different hardware: remove the side brush, install the sweeping brush and the carpet vacuum attachment, then select the mode; Pudu rates that mode at four hours of runtime and restricts it to short-pile carpet. It is a deliberate changeover, not something the machine does mid-run. The CC1 Pro is the version that adds automatic floor-type detection — hard floor gets the wet programme, carpet is vacuumed dry — which we compare in detail in CC1 versus CC1 Pro.

What tips the decision is how much carpet there is and in what pieces. Scattered carpet islands in an otherwise hard-floor building — a few meeting rooms, a reception rug — rarely justify their own machine: a scrubber with no-go zones plus manual vacuuming of the islands costs less effort than a second robot and a second service routine. Contiguous carpet from a few hundred square metres per floor upwards is where a vacuum starts to earn its place. And one detail from the Nexaro manual belongs in mixed-floor planning: the NR 1700 crosses objects up to 15 mm in height, explicitly including door thresholds and carpet edges — where a carpet edge is higher than that, the transition is a boundary, not a passage. Which machine class fits your building at all is the subject of which cleaning robot suits which operation.

A vacuum is loud by construction — the working principle is a blower, and a blower makes noise. Where manufacturers publish figures, they read as follows: the Whiz data sheet states 62 dB in normal mode; the NR 1700 data sheet states 49 dB(A) in Eco mode and 57 dB(A) each in Balanced and Performance, and those values, unusually and helpfully, were measured on carpet. For the MT1 Vac, Pudu publishes no noise figure at all — not in the product page, not in the press release, not in the partner brochure. We therefore do not put a number on the site and plan the machine as loud. That is the safe direction of error for a twin-fan commercial vacuum.

For hotels this dictates the schedule, because carpet in a hotel is mostly on guest floors, and guest floors have sleeping guests. Corridor vacuuming happens inside the daytime housekeeping window, exactly as it does with a manually pushed vacuum — never at three in the morning in front of guest room doors. The Whiz fits this pattern particularly well, because it needs a person anyway: housekeeping teaches the route once, starts the robot in the morning window and swaps the battery when it runs down. Lobbies, conference and event areas follow the same logic, only with wider windows between events.

In offices the pattern inverts. At night the floor is empty, noise costs nothing and the machine has the whole area to itself — this is the home ground of the class. What matters then is whether the robot manages the night on its own: the NR 1700 maps by itself, returns to its dock and reports over its built-in mobile connection; the MT1 Vac has an automatic charging station. The Whiz does not run unattended through a night — its run ends with the battery and a person inserts the next one. What else needs settling before unattended night runs — access, keys, escalation when a machine stops — is in our article on night operation.

Four kinds of work stay with people. First, edges and everything the lane pattern does not reach. Pudu describes edge-to-edge cleaning for the MT1 Vac — high-precision sensors keeping the machine aligned to walls and pillars — and even documents a hand-vacuum extension for sofa sides, walls and glass surfaces; for the Whiz there is no manufacturer statement on edge precision that we would quote. Either way, skirting corners, chair and desk legs and the area under low furniture remain manual. Second, stairs: all three are floor machines with drop sensors, and stairs are the boundary of their world, not a task.

Third, spots and stains, and fourth, periodic deep cleaning. Both are wet work on a textile covering, both stay scheduled human tasks, and both should be named in the cleaning specification alongside the robot rather than assumed into it. Consumables belong in the same plan: the Whiz lists HEPA filters, dust bag and brush as consumable parts, the MT1 Vac works with disposable dust bags, and among the three only the NR 1700 has an officially washable filter — the H13 with 530 cm² of filter area. Where an official source does not describe a filter as washable, we plan it as a wear part on a replacement cycle.

Before an installation on carpet we settle six points, in this order: the pile height and covering type per area — 15 mm is documented for the NR 1700, everything else is inspected on site; the carpet share per floor and whether the areas are contiguous; the operating window, meaning who is in the building and when it may be loud; the filter class, which for allergen-sensitive buildings means specifying H13 up front instead of retrofitting it; the emptying rhythm, where a 1.4-litre container and 20 litres of capacity are roughly a factor of fourteen apart; and finally, in writing, what explicitly stays manual — edges, stairs, stains, periodic deep cleaning — and who does it. That last point prevents more disappointment than any specification. If you want to see the machines run on your own carpet, that is what a demo is for.