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Roborock S4 robot vacuum review: Updated design takes on obstacles as it thoroughly cleans

Written by Matthew Miller, Contributor on

Roborock S4 vacuum

8.4 / 5

pros and cons

  • Sleek, updated black design
  • Powerful suction levels
  • Strong drivetrain for limited obstacles
  • Customizable zone control with full mapping functionality
  • Reliable, always returns home for charging
  • New Roborock dedicated application
  • No mount for the cleaning brush
  • Limited Alexa support
  • No Google Assistant support

After trying out a few robot vacuums and experiencing frustrations with reliability, I found the Roborock lineup that has been knocking it out of the park for a year. However, mopping with water was a function I never used beyond initial testing so I'm very pleased to see the new Roborock S4 leave that function behind while coming in at a reasonable $400 price point.

The Roborock S5 and Roborock S6 are fantastic robot vacuums that I highly recommend for their speed, smartphone connectivity, thorough cleaning, and reliability to perform their intended function. However, I clean my awesome acacia wood floors with Bona and only used the water tank mopping feature on those vacuums for testing. Do others actually only mop their floors with water?

The new Roborock S4 is now available on Amazon for $399.99 and brings all of the amazing functionality we saw on these earlier S6 and S5 models with mopping capability removed. It also has an improved sleek black design with an updated drive train that backs it off obstacles so you should see even fewer incidents of getting stuck. There is also now a Roborock smartphone app, rather than the Roborock vacuum being part of the Mi Home application.

Also: Roborock S6 robot vacuum review: Faster, quieter, and more efficient than its predecessor

I used the Roborock S4 to vacuum my lower level that is comprised primarily of acacia hardwood floors with a few area rugs. Our pomeranian and chihuahua, along with two cats, spend most of their time on this level so the pet hair builds up daily. This is also the entry level where people come into the house through the garage, front door, and back door so there are places where rocks and other outside objects can be brought into the house. The Roborock S4 performed well and I have to admit the sleek new black look is attractive.

Hardware and box contents

The Roborock S4 arrived about a month ago in a fairly plan brown cardboard box with Roborock branding. Inside you will find the Roborock S4, extra filter, dock charger, power cable, and cleaning brush. Unfortunately, there is no internal mount for the cleaning brush like we saw on the S6 so you will have to find a secure place to store it between cleanings.

I've been using the Roborock S4 for about a month now and it has performed flawlessly; always cleaning thoroughly, following the map and my specified No-Go zones precisely, returning to charge up without failure, and rarely informing me of any situation when it gets stuck. Previous robot vacuums I tested failed to line up on the charger so were dead most of the time I wanted to vacuum, lost the saved map of the house and constantly remapped the level, and did not perform as thorough of a job as the Roborock S4.

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The Roborock S4 looks similar to the S5 and S6 design with the raised laser distance sensor (LDS), round form factor, and single side brush. However, it has been updated with a black color with a lid that you can see partially through near the LDS and over the dust bin, a LDS cover that is moved further towards the edge, a single round button assembly that is moved towards the front that nests within an opening in the lid, and a sleeker charging dock. It's a bit more elegant looking than the S5 and S6 models, to be honest.

The round button assembly has two buttons that light up with white LEDs and show power and home icons on them. These buttons are accessible with the lid closed or open.

Roborock S4 robot vacuum review: in pictures

The top houses the LDS (laser distance sensor) in a round area that rises above the top of the vacuum about half an inch and is just a couple inches from the back edge. The S4 overall height is less than other vacuums I have tested so it is able to go underneath most of my major furniture. I was surprised that it fit under my kitchen cabinets with the foam floor mats I have in place since other vacuums required me to remove these mats before vacuuming. In front of the LDS is the large lid to access the dust bin and two front buttons on the vacuum.

Lifting up the lid reveals the Wi-Fi indicator light and the dust bin with a removable filter for fine dust. On the S5 and S6, the cleaning brush was stored under the cover, but that is no longer the case. The dust bin design is very similar to the S5 and S6 with a black color instead of white.

A wall sensor sticks out from the front half of the vacuum with a rotating side brush over on the front left side peeking out from under the vacuum. The S6 side brush was on the back right side. The side brush on the S4 is the same design as the S6 with five silicone pieces that are split in half. The speaker and an air vent are found around the back with a more traditional grille design with many holes in the plastic side shell.

Also: Roborock S5 robot vacuum review: Powerful, intelligent competitor takes care of your chores

On the bottom, we have two large main wheels with silicone tire treads, again now in black, that are sure not to scuff up your hardwood or tile floors. There is a main brush, the side brush, and an omnidirectional wheel. The charging contacts are now long bars on the back of the vacuum, rather than being on the bottom. This may lead to better connections as the vacuum builds up dirt on the bottom. Four cliff sensors are positioned forward of the two large drive wheels and keep the S4 from tumbling down the stairs. There were two such sensors on the S6.

The charging dock has a rear cover that hides the cable management compartment so you can setup the S4 and have a professional setup where the cable runs to an outlet for charging up the vacuum. The charging contacts are on the front face of the dock, rather than on the bottom. So far, the Roborock S4 has been able to return to its home and charge up between each vacuum evolution.

The dust bin is longer and not as deep as the one in the S5 or S6, but has proven to hold one to two vacuum sessions for the approximate 730 square feet of coverage on my wood floors with a few raised area rugs. The capacity is not listed on the website, but appears to be the same as the previous Roborock vacuums. My floors look pretty clean, but it is stunning to everyone how much dog hair and other things are picked up by this vacuum on a regular basis. There is a washable E11-grade strainer/filter in the dust bin that is rated to provide 95 percent filter performance after a year of normal use. It's easy to rinse the filter out and you get one extra in the retail package.

Software and services

Previously, the Roborock vacuums used the Mi Home app and did see regular improvements to make the vacuums very capable. Roborock now has its own iOS and Android app and despite the current low ratings in these app stores it has proven to work very well for me while also reducing confusion with including other Mi products in a single app.

Simply walk through the setup of the Roborock app to connect your phone or tablet to the Roborock S4. The great thing about this Roborock app is that you can install it on multiple devices, which can all control the Roborock S4 with the same login and saved app. This means that my wife, my daughters, or I can all control the vacuum from our devices. Unlike some other robot vacuums I have tested, the Roborock S4 map translates over to all connected devices. This is great for a phone reviewer like me, but also for employees or family members who need control over the office/home vacuum.

Roborock S6 robot vacuum review: in pictures

The new Roborock application launches with three main tabs showing notifications, robots, and profile. The Robots tab, center page, launches with the app and shows you the robot or robots you have connected to the app. Tap the robot you want to manage and the floor plan (after it creates it the first time), buttons for No-go zone/restore map options and four cleaning modes (silent, standard, medium, and turbo) below the map, buttons for All or Zone below that, and finally charge and clean buttons at the bottom of the display. The current area cleaned, battery status, and cleaning duration appear above the map so you know if the vacuum will be able to clean your entire area before needing a charge.

Also: Mi Electric Scooter review: Complete that last mile commute with ease

In the center you will find options for room, all, or zone cleaning with buttons below that to dock/charged or clean. Zoned cleanup lets you designate one or more square zones for targeted vacuuming. This can be useful for high traffic spots or if you have a particularly dirty area that needs some immediate attention.

You can tap the menu option in the upper right to access vacuum settings, timer, voice and volume, go to, cleaning history, fittings and maintenance, and user manual. Vacuum settings include naming your vacuum, saving the map, showing the indicator light, and more. You can also setup do not disturb times so the vacuum will not clean or play voice alerts. This can be setup for business hours or sleeping hours.

The timer in this new software is simply awesome. You can create timed vacuum sessiong for various times and days with even various cleaning modes selected for various times and days of the week. I've never seen a robot vacuum with this much capability to control and direct the entire experience. This is perfect for the office or home environment.

Also: Best Robot Vacuum Cleaners for 2019 CNET

The voice and volume settings let you choose a volume leel and various languages with one option for English with a female voice. The Go to option lets you specify a selected location for cleaning, which is helpful if there is a spill or other targeted area of concern that you must clean now. The rest of the settings are useful, including the fittings and maintenance section that gives you lifetime of the filter, side brush, main brush, and sensors before they need cleaning or replacement.

Daily usage experiences and conclusion

The Roborock S4 is available now on Amazon for $399.99 and I've been telling neighbors this is the one to buy. The S5 is priced at $499.99 and the S6 at $649.99, but with no real need for mopping or full support for voice assistants I think the S4 is probably the best value.

While the S5 and S6 worked with Amazon Alexa, I never used this function past the trial period since the smartphone application gave me much more detailed control and once a timer was setup there was no need to create confusion with a voice assistant. There is no advertised support for voice assistants with the S4 and while that doesn't bother me you should be aware of this limitation.

Also: Hands on with the Roborock C10 robot cleaner: Great cleaning for the ultra stylish home and office

I like the rollout of the new dedicated Roborock application that just lets you focus on controlling and managing your robot vacuum rather than Mi Home products you may or may not have on hand. The application is very powerful and if history proves itself the application and Roborock S4 will improve over time. The map and software was very stable and functioned perfectly over the past month.

One of the main advertised features of the S4 is its updated drive train to handle obstacles better and I can tell you this vacuum had no trouble fighting thick rug edges it had to rise above and I never received any failure notifications that it was stuck. My wife thought it was a bit too aggressive as the wheels worked hard to get over rugs that had edges that flipped over, but there were never any marks in the hardwood floors despite the effort of the Roborock S4 to rise above the obstacle.

The Roborock S4 has a large 5200 mAh battery that is rated to run for 150 minutes, 2691 square feet, between charges in standard mode. It took the S4 about 80 minutes to clean 731 square feet in my lower level, but that was in medium mode with several spaces and a ton of obstacles in the way too. It's very interesting to check out the vacuum history to see the results of the algorithms used to cover the area thoroughly, which lets you verify the entire surface was cleaned very well.

The Roborock S4 has a very high rated suction, advertised that it can lift AA batteries, and I clearly saw full dust bins with every session, despite the overall impression the wood floors were clean. If I can just get a Roborock that empties the bin itself I will never have to do anything more than lift a finger to vacuum. I was extremely satisfied with the Roborock S4 and at $400 I highly recommend this for businesses and homes who want to eliminate one chore in the house.

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