Review of the Xiaomi Robot Vacuum S20. A home assistant with dry and wet cleaning

Robot vacuum cleaners have long ceased to be something exotic, becoming familiar household cleaning assistants. While previously the mention of features like a laser room scanner, wet cleaning, and smart integration into smart home systems was exclusive to top-tier models, today even mid-range and entry-level models offer these features “out of the box.” An example of such a modern and relatively affordable robot vacuum cleaner is the Xiaomi Robot Vacuum S20, which this review is dedicated to.

Technical Specifications

Packaging and Contents

The box in which the Xiaomi Robot Vacuum S20 is sold is brightly designed and equipped with a handle for easy carrying. A factory sticker is applied to the lid, allowing you to check whether it has been opened before you. Inside the box, the robot vacuum cleaner is securely packed and placed in a molded cardboard cradle. This type of protection should easily withstand long-distance transportation.

The Xiaomi Robot Vacuum S20 package includes: the robot vacuum cleaner itself with the model code Xiaomi D106, a three-blade side brush, a wet cleaning attachment with a pre-installed cloth, a charging dock (model CDZD106), and a power adapter for the dock.

The version reviewed is intended for sale in our country, so the power adapter comes with the correct plug without the need for adapters.

Appearance

The appearance of robot vacuum cleaners has generally become standardized. Most household models are designed as small cylindrical towers. The body diameter of the Xiaomi Robot Vacuum S20 is 32.5 cm, and its height, including all protrusions, is 98 mm.

The model is equipped with LIDAR, so the top of the body features a protrusion that houses and protects the rotating orange laser scanner unit. On the front, there is also an oval tinted window for the infrared sensor used to locate the charging dock.

The top profile is close to a circular shape, with a prominent movable bumper at the front. This bumper acts as a collision sensor, signaling to the robot that it has encountered an obstacle not detected by the LIDAR. A rubberized strip is attached to the lower part of the bumper at the front to reduce the risk of scratching objects during collisions. On the top front of the body, there are two illuminated physical buttons: one for power on/off and the other for returning to the base station.

The bottom layout is classic, with two large driving wheels on the central axis at the sides and a supporting rotating roller at the front. The roller is tightly secured and could not be easily removed. Additionally, three optical cliff sensors are placed along the arc of the front bumper. These sensors detect height differences, such as stairs, and prevent the robot from falling off surfaces with significant height drops.

The wheels are fairly large and feature a tread pattern that ensures excellent traction on various surface types. Like most robot vacuum cleaners, they are partially recessed into the body and spring-loaded.

The main turbo brush is located in the central part underneath. It consists of an orange plastic spindle with bearings on the edges, fitted with orange rubber blades and a wavy brush with stiff black bristles.

To remove the brush from its housing, you first need to detach the plastic cover, which is secured by plastic clips.

The dust container in this robot vacuum model is combined with the water tank. It is removed from the back by pressing down on a large orange latch.

Behind the container are the intake opening for debris suction from the turbo brush and the suction motor openings, which are covered with a protective mesh.

The container features a convenient slot for storing the cleaning tool. The tool is a flat brush with a plastic handle, one end of which includes a small blade for cutting hair and threads tangled around the turbo brush. To prevent collected debris from falling out of the container during removal from the robot vacuum, the intake opening is sealed with a transparent plastic “door.”

The container’s lid, in the section for debris, has a flip door with a latch at the air outlet, where a dust filter is installed. During cleaning, it is recommended to rinse and dry the filter instead of vacuuming it, to avoid prematurely damaging the fibrous structure by stretching the threads.

The water filling hole is sealed with a rubber plug, ensuring watertightness even if the container is turned upside down. However, fully submerging the container in water is strictly prohibited.

The container comes with a removable plastic bracket with Velcro strips for attaching the cleaning cloth used for mopping floors. The cloth is fitted onto the bracket by sliding the fabric “pocket” over the long section and securing the curved part with Velcro strips, similar to hook-and-loop fasteners.

Preparation for Use

Before starting, it is necessary to install the included side brush. To do this, simply place it onto the guide until it clicks into place.

The brush extends about 5 cm beyond the body, so it does not fully compensate for the rounded shape of the body during cleaning.

The bracket with the cloth snaps into place using two guides on the bottom of the container when wet cleaning is required.

Before the first cleaning session, the manufacturer recommends fully charging the vacuum cleaner on the included charging station. To do this, place the station somewhere in the room, ensuring about half a meter of free space on the left and right sides, and approximately one and a half meters in front. Then, connect it to the power adapter, position the vacuum cleaner nearby, and press the button with the house icon on the vacuum. The vacuum will automatically detect the correct position of the charging station and dock itself for charging.

All further actions for configuring and managing cleaning cycles and types must be performed using dedicated mobile apps.

Mi Home Mobile App

For its smart home ecosystem, including controlling robot vacuum cleaners, Xiaomi offers the free Mi Home app, available for smartphones and tablets running the Android operating system, and the Xiaomi Home app for Apple devices running iOS. These apps can be downloaded, for example, from app stores such as Xiaomi GetApps, Google Play, and the Apple Store.

The robot vacuum cleaner reviewed here was tested in combination with the latest version of the Mi Home app, version 9.10.700.8865 for Android.

Initially, the robot vacuum cleaner must be added to the list of devices in Mi Home by performing an automatic search or manually selecting it from the extensive list of devices and specific models.

A step-by-step setup wizard will guide you through all the stages, providing detailed instructions on what actions to take. This will include resetting the device settings and configuring the Wi-Fi network parameters through which the robot will connect to Mi Home internet services.

After the initial connection setup, if firmware updates are available for the robot vacuum cleaner, you will be prompted to update it to the latest version to apply all fixes and improvements identified since its factory release.

Next, you can proceed to detailed configuration. For added convenience, you can immediately select Russian as the voice notification language in the “Settings” menu (accessed by tapping the three dots in the upper right corner) → “Additional features” → “Select language.”

Before the first cleaning session, it is recommended to initiate the room mapping process. During this phase, open all rooms, remove as many small items from the floor as possible, and start the mapping process. The robot vacuum will activate LIDAR, move around to explore the space, and simultaneously create a map, which is displayed in near real-time in the app. The duration of this process depends on the complexity and size of the area, but it is significantly faster than a cleaning session and usually takes just 5–10 minutes. Detected rooms will be automatically assigned numbered names. Later, you can split them or rename them as desired to make it more convenient for use in automated cleaning scenarios.

The app offers many features for fine-tuning cleaning processes, setting restricted zones, and automating tasks linked to events triggered by other devices in the ecosystem. Using Mi Home, the robot vacuum cleaner seamlessly integrates into the smart home infrastructure.

Usage Features

The Xiaomi Robot Vacuum S20 supports three cleaning modes: “Vacuuming,” “Wet Cleaning,” and their simultaneous use. For vacuuming, there are three preset suction power levels: “Silent,” “Standard,” and “Turbo Mode.” Naturally, these settings affect not only the suction strength but also the noise level and battery consumption. For heavy dirt or the need to collect scattered small debris in a specific spot, “Turbo Mode” can be used, while “Standard” is sufficient for most cases. In “Silent” mode, the actual noise level changes only slightly compared to “Standard,” but the suction power is significantly reduced, making it unlikely to be in high demand.

During dry cleaning, the robot vacuum first moves along the perimeter of the room where it started and then cleans the interior using a zigzag pattern. After completing the room, it moves to the next one and repeats the algorithm.

The cleaning quality is excellent for its class. The robot vacuum effectively sucks up small debris and leaves virtually no missed spots, thoroughly covering the entire floor surface in a zigzag pattern. The air outlets, which expel dust-free air, are angled upward, so the vacuum does not blow fine dust and debris around while turning. However, due to the disc-shaped design of the body, it does not sweep out fine debris from corners, as the side brush does not extend far enough beyond the body. This is a design limitation common to most similar models.

The Xiaomi Robot Vacuum S20 handles obstacles well. Climbing onto rugs poses no problem for it. It even manages to hop over laundry rack legs with a diameter of 16 mm quite confidently, with minimal slipping. However, slippery surfaces are a bit more challenging. The robot was unable to cross floor scales with a glass top, repeatedly bumping into them with its bumper and underside from all sides.

During wet cleaning, two options are available: the first is a zigzag motion similar to dry cleaning (standard wet cleaning), and the second is a more thorough Y-shaped back-and-forth movement (professional wet cleaning). The second option provides a more meticulous cleaning of floor surfaces but increases the cleaning time.

It is important to remember that the Xiaomi Robot Vacuum S20 is not a washing vacuum cleaner but a robot vacuum with a wet floor wiping function, so it cannot be used to collect spilled liquids. For wet cleaning, there are three water flow settings for the cloth: “Low,” “Medium” (set by default), and “High.” For laminate floors, the medium level is sufficient. This setting moistens the surface no more than if you used a mop with a moderately wrung-out cloth, and it dries quickly.

On linoleum, tile, PVC flooring, or other moisture-resistant surfaces, if there are dried dirt spots, you can enable the “High” water flow setting in combination with “Professional Wet Cleaning.”

The robot vacuum navigates the room well. Large objects are correctly recognized by the LIDAR, avoiding direct collisions. The robot moves along sofas and cabinets at a distance that allows the side brush to pick up debris along the edges of surfaces. Occasionally, it leaves a couple of centimeters of extra clearance, missing some debris along walls or long pieces of furniture. Other times, it passes perfectly, even sweeping up some dust from under the furniture.

LIDAR does not detect mirrored surfaces, such as full-length mirrored wardrobe doors, and identifies them only through light collisions, after which it adjusts its path to “hug” the surface while rotating slightly. This is less than ideal, as experience with older vacuum models has shown that over time, scratches or “drawn” streaks from the plastic bumper can appear on glass.

Another challenge for the LIDAR is long, semi-transparent curtains that drape onto the floor. During the first cleaning, the robot vacuum became entangled in a curtain, wrapping it around the side brush, and stopped with an error message.

Small objects and lightweight children’s toys are often pushed around by the robot vacuum without triggering the collision sensor. If you want to avoid searching for where the vacuum has shoved small items or untangling a cable wrapped around the turbo brush, it’s better to clear the floor before starting a cleaning session. This, incidentally, is one of the main reasons why the reviewer abandoned early-generation iRobot vacuum models a few years ago, as it was quite tiring to pick up all the small items scattered by children before each cleaning.

The robot vacuum reacts moderately to pets. A cat attempting to play with its rotating brush did not disrupt the cleaning process. The robot only maneuvered around her when she sat directly in front of it, ignoring her playful “attacks” from the side.

Simulated cat waste made of modeling clay was ignored by the vacuum, which drove right over it. Therefore, it’s best to mark the location of pet litter boxes as a no-go zone on the cleaning map to avoid mishaps.

It’s also advisable to exclude pet feeding areas from the cleaning zone, as the robot vacuum can easily push light, low water or food bowls, spilling their contents. Ultimately, water getting into the vacuum could lead to malfunction.

Fortunately, restriction zones, such as virtual walls and rectangular no-go areas drawn on the room map in the Mi Home app, are fully respected by the robot vacuum and are bypassed correctly.

During testing in a standard three-room panel apartment of about 70 m², one cleaning cycle used approximately half of the battery charge. However, the actual cleaning area was significantly smaller due to furniture placement and restricted zones. Most likely, the built-in battery’s charge will suffice for both dry and wet cleaning of an apartment up to 100 m² in size.

Cleaning

The dust container in the Xiaomi Robot Vacuum S20 is easy and convenient to clean. Simply open the lid and empty the contents into a trash bin. If necessary, the mesh in front of the filter can be easily cleaned using the included brush.

It’s just as easy to remove hair or threads tangled around the side brush, as it can be detached from the guide in one motion and reattached just as effortlessly.

The turbo brush quickly collects long hair, which, as with all robot vacuums of similar design, can be difficult to remove. The blade on the cleaning tool is helpful for this. After cutting through the tangled hair, it becomes easier to remove it from the brush. The tip of the tool can also be used to pick out hair around the bearings.

The most tedious process is maintaining the cloth for wet cleaning. It needs to be washed and dried manually after each mopping session. Since the vacuum cleaner and charging station do not have a built-in drying module, leaving the cloth damp can result in an unpleasant musty smell or even mold. The manufacturer honestly warns about this on a sticker placed on the dust container.

The robot vacuum’s consumables have a recommended replacement schedule: the main brush—360 hours, the side brush, dust container filter, and wet cleaning cloth—180 hours of operation. The remaining usage time for each item can be checked in the app under the “Settings” → “Consumables Usage” section.

Conclusion

Before purchasing the Xiaomi Robot Vacuum S20, or any similar robot vacuum models, it’s important to understand that this is a device designed to assist with house cleaning, allowing it to be done less frequently, but it does not take over 100% of the work. Additionally, a robot vacuum with a wet cleaning function should not be treated as a washing vacuum cleaner—it has entirely different features and capabilities.

The Xiaomi Robot Vacuum S20 is an advanced representative of the modern generation of smart robot vacuums, offering strong capabilities for automating daily dry floor cleaning and subsequent wet wiping of dust residues. It helps extend the intervals between deep cleanings and effectively eliminates most small debris, dust, pet hair, and human hair from floors, leaving only hard-to-reach areas—where the robot cannot access due to design limitations—for manual cleaning.

Advantages of the Xiaomi Robot Vacuum S20:

• Good quality dry cleaning;
• Wet mopping of floors;
• Decent claimed suction power of up to 5000 Pa;
• Quick room mapping and precise navigation;
• Convenient dust container;
• Convenient storage for the brush with a blade;
• Russian-language voice notifications;
• Protection against falling from stairs;
• Quiet operation in standard mode;
• Remote tracking of the cleaning process in real time;
• Firmware updates “over the air” (Wi-Fi);
• Advanced automation app for smart home devices, Mi Home;
• Integration with Google Assistant and Amazon Alexa.

Disadvantages:

• Detection of mirror surfaces only via collision sensors;
• The black model’s body is prone to smudges and dirt;
• The protruding lidar on top slightly limits the ability to clean under low furniture.

Potential drawbacks:

• The mop for wet cleaning needs to be removed and dried after each use;
• No spare consumables included in the set;
• Room maps are uploaded to an online storage via the app.