Great for the price
Powerful suction
Good battery life
Washable air filter
Voice activation
Excellent mapping
Quiet cleaning
Low profile


Smallish dustbin
Only available in black
Gets dusty/fingerprinty
Not for high-pile carpet

Bottom Line
by Roborock

The Roborock S4 is one of the best robot vacuums at this price range, punching well above its weight. With powerful suction, advanced features, and a long-range battery, the Roborock S4 is a great buy.

What is the Roborock S4?

The Roborock S4 is a voice-activated robot vacuum cleaner. Unlike some of Roborock’s other offerings, which include both vacuum and mop capabilities, the S4 is exclusively for vacuuming. It can be controlled with your voice, the two buttons on top (power and home) or with the Roborock app.

Note: A couple of Roborock’s mop-and-vacuum robots are currently on sale at Amazon!

How does it work?

The Roborock S4 is a circular robot vacuum with an average-sized 420ml dustbin. It docks into a charging station that connects to mains power. The S4 automatically returns to the dock once cleaning is completed, when you tell it to, or when its battery needs to recharge. A built-in speaker will announce when it starts cleaning and when it’s finished.

There’s a companion app for Android and iOS you can use to “enter” the robot, although the S4 can still be used without it. The app lets you remotely control cleaning and docking, and provides a convenient cleaning overview. This includes a map of where the S4 has cleaned, cleaning duration, the area covered, and the remaining battery life.

What are the Roborock S4 specs?

The S4 has maximum suction of 2,000Pa, which is more than enough for most common household debris and is enough to lift an AA battery off the floor. At 19CFM, the Roborock S4’s airflow is solid for a robot vacuum and is around one-third to one-fifth of your average household vacuum.

The Roborock S4 battery is massive. At 5,200mAh it is much larger than a lot of other comparable robot vacuums, meaning more cleaning between charges. As a rough guide, the S4 cleans both floors of my 875-square-foot apartment in an hour but its battery can last for up to 150 minutes.

At 5,200mAh, the Roborock S4's massive battery means more cleaning between charges.

Given a less complex layout than mine, the S4 can apparently handle up to a 250-square-meter (~2,700 square foot) home on a single charge. I’m not quite sure about the math here unless your home is a tennis court, but I’ll admit my apartment does require an awful lot of twisting and turning to navigate.

Roborock S4 review charging contacts

How well does it clean?

My two-floor apartment is almost completely floored in tiles or wood, with the occasional rug or square of low-pile carpet. Given my relatively “easy” flooring situation, the S4 had no problems with suction and it could clean both levels very well with battery to spare.

The bristle-and-fin main brush managed well and didn’t get tangled with hair as much as some other robot vacuums I’ve used. If it does need cleaning, you can simply pull the end caps off the brush to make it a quick and easy job. Its floating design means it adapts well to different floor coverings, maintaining an optimum height for the best cleaning.

The S4's low profile means it even fits underneath my couch, something not all robot vacuums can manage.

I was also impressed by the S4’s coverage, with it never failing to venture everywhere barring the areas it couldn’t access. The Roborock S4 is only 9.6cms/3.9-inches high, which means it even fits underneath my couch, something not all robot vacuums can manage. It uses a simple zigzag pattern for complete coverage or you can also drop a pin on the map using the app and have the S4 navigate there directly.

The Roborock S4 offers various cleaning modes for different vacuuming jobs. These consume more or less power and produce more or less noise depending on the task at hand. In the default balanced mode, the S4 hits a max of 59dB, similar to most floor-standing fans. You can also switch to silent mode or beef things up with max or turbo mode.

Roborock S4 review charging dock

Can it replace my normal vacuum?

As with any robot vacuum cleaner, the Roborock S4 isn’t necessarily meant to be a complete replacement for your canister or upright vacuum cleaner. It is capable of handling things alone if your home is easy to clean like mine. I wouldn’t recommend throwing away your existing vacuum cleaner as it may still come in handy.

For most people, you’ll still need to vacuum on occasion to get those hard-to-reach places or something the S4 couldn’t pick up. But the frequency with which you’ll need to vacuum yourself will be dramatically reduced. For me at least, that makes the S4 absolutely worth it.

Whether a robot vacuum is up to the task of cleaning your particular floors depends on how aggressively dirty they get and with what. Bigger spills and high-pile carpets are still going to need a more powerful vacuum, but for everyday maintenance the Roborock S4 has you covered.

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How does it navigate?

The Roborock S4 uses a LIDAR-based Laser Direct Structuring (LDS) navigation system to map your home. The little protrusion on top of the S4 scans the surrounding area at 300rpm to within 2cm accuracy. An adaptive route algorithm calculates the most efficient path for your floor plan.

11 different sensors, including four cliff sensors, help it avoid obstacles or falling down stairs. Because it uses laser, it can even clean in the dark and an improved drivetrain makes it harder to get stuck. Some other vacuums I’ve used get stuck on a little lip near the top of my stairs, but the S4 managed to breeze right over it.

The Roborock S4 can clean in the dark and an improved drivetrain makes it harder to get stuck.

The Roborock S4 saves the maps it creates, so you can take it up or downstairs and it will always know where it is. You can also use the Roborock app to create different zones or rooms in your home and have the S4 clean only one. This is particularly handy if, say, you spilled something in the kitchen and don’t want the entire house cleaned.

Roborock S4 review top down view

What else can it do?

One of my favorite features is voice activation. Like my other smart home appliances, I can simply tell the Roborock S4 to go clean the kitchen without having to pull my phone out. With the app, you can set up do not disturb parameters and cleaning schedules, set virtual no-go zones, change cleaning modes, and activate or stop the S4 at any time.

If the Roborock S4 encounters any problems while cleaning, you will receive a notification letting you know. This might include a blocked brush or a full dustbin. And if for some reason the S4 gets lost, you can use the Find My Robot feature in the app to locate it. Because it has a speaker, it will call out “Hi, I’m over here.” The app can also show the robot’s real-time location.

What about filters and brushes?

The transparent plastic top of the Roborock S4 means you can see if the dustbin is full at a glance. To empty it, just lift the lid, pop out the tray, empty and rinse under the sink if necessary. Both the anti-tangle main brush, side brush, and E11 air filter are easily washable too.

The Roborock app keeps you updated on when each brush, filter, or sensor needs cleaning or replacing.

The Roborock app keeps you updated on when each brush, filter, or sensor needs cleaning or replacing, tracking the hours of use against recommended maintenance schedules. You can also use the app to access a complete cleaning history including times, dates, duration, and area covered. A historical tally keeps track of just how many hours you haven’t spent vacuuming since you got the S4.

Roborock S4 review bottom view

Roborock S4 review: Is it worth it?

At $399 the Roborock isn’t cheap, but it does offer an awful lot for the price. It’s far more capable than many other similarly priced robot vacuums, with better range, cleaning, and functionality. I’ve tried cheaper robot vacuums in the $200-300 range and for my money, the Roborock S4 is worth every cent.

It has excellent navigation and mapping, powerful suction, and tons of additional features in the well-thought-out app. Whether you hate vacuuming or you want to give the gift of more free time to someone else, the Roborock S4 is a solid purchase.

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