Roborock S4 Hands-On Review: an Ideal Robot Vacuum for Complicated Home Layout

Review of:
Roborock S4
Brand name:
Roborock
Model:
S4
Reviewed by:
Natalie Red
Rating:
Published On:
September 23, 2019
Edited On:
December 2, 2019

Summary

The newest Roborock S4 is one of my favorite robot vacuum cleaners. This automatic cleaner is an absolute winner in the price range. It provides the most efficient and intelligent navigation I have seen. It cleans my apartment faster than all the robots I've tested. I love the new design with the semi-transparent lid. The S4 is more than capable of providing impressive cleaning performance in homes with bare floors or thin carpets. It lacks a wet mopping feature, but it does have a revamped drivetrain. Roborock reduced the climbing ability of the robot to 1.5 cm, which means it is not suitable for thick carpets; instead, they increased the reverse power which is always stronger than its  forward movement. Thanks to this, it has better maneuverability and the ability to free itself from tight places between furniture and corners in cluttered rooms not to mention a complex house environment. The newest Roborock app feels sleeker, faster and more stable than the Mi Home app. I highly recommend the Roborock S4 for those who live in a home without carpets (or with thin low-pile carpets). The cleaner has a larger dustbin than its predecessors and an easy-to-maintain roller brush, so pet owners will be happy with it as well. The robot costs less than other big-name brand competitors.

Check it on Amazon  

Roborock is a fast-growing hi-tech company that specializes in intelligent home robotic devices. It makes robot vacuums under their own brand, Roborock, as well as producing robot vacuums for China's largest technology company, Xiaomi. Previously, we tested the Roborock S5 and S6. After testing and comparing them with similar devices, we came to the conclusion that these robot vacuums have the most efficient and intelligent navigation on the market. The Roborock S4 brings some extra features to the previously released S5 and comes in about $100 cheaper on Amazon.

The S6 model surprised us with very precise and accurate navigation that we have never seen. But it seems like the newest Roborock S4 has even more intelligent navigation.

The idea behind the Roborock S4 is to provide a reliable, LIDAR-based vacuum only option to users who might not necessarily want the mopping function.

The Roborock S4 fresh design

The S4 was specially designed to navigate easily in complex environments. A revamped drivetrain and improved navigation help to free it from obstacles in narrow places, corners and among furniture. We thoroughly tested this robot for a week, and in this review, we share our thoughts about the new Roborock S4. Who is it for? What has been improved? You can find the answers below.

A new updated design

The Roborock S4 does not look like anything we've seen before. I was surprised to see that the lid is semi-transparent, it looks unique and fresh!

The transparent lid of the Roborock S4 with a visible Hepa filter
The semi-transparent lid of the Roborock S4
The Roborock S5, S4 and S6 design
Roborock S4 compared with S5 and S6 models

The buttons also look nothing like the Roborock we used to know. No more separate buttons; now it has one big button divided into two parts. One sends the robot to the dock while the other starts and stops the machine. The lid is glossy, which means fingerprints will be noticeable.

The charging dock of the Roborock S4
Roborock S4 with the charging dock

The main roller brush looks the same as the one in the Roborock S6. Compared to the S5 model, it has increased by a 250% bristles density and includes removable tips so any hair that gets tangled up can be slid off.

The Roborock S4 accessories
The Roborock S4 extra accessories that come in the box

The brush has the same size and form and can be replaced with the S5/S6 model's roller brush. One side brush is rubber, the same as the Roborock S6 is equipped with.

The rubber side brush
The Roborock S4 rubber side brush
The underneath view of the Roborock S4: a rubber side brush, big wheels and an upgraded cleaning roller
The Roborock S4 underneath

I like that Roborock equipped the S4 robot vacuum with a bigger dustbin (compared to other Roborock models).

The semi-transparent lid of the Roborock S4 with a dustbin

The Roborock S4 dust box with a washable HEPA filter
The S4 dustbin with a HEPA filter
The Roborock S4 vs. S5 vs. S6 dustbin containers compared
The Roborock S4, S5, and S6 dust containers compared

It has the same HEPA E11-grade washable filter used in previous models. The filter can be easily cleaned by running it under the kitchen tap and letting it dry before using. The filter traps mold, dander, and other particles as S4 cleans, and is definitely helpful for allergy sufferers. Since it is washable, it can be used longer.

Under the lid of the S4
Under the lid
S4 underneath
The dustbin installed

The difference between the S6 and S4 models:

  • No mopping. The Roborock S4 does not come with a mopping attachment.
  • Bigger dustbin. The S4 has a bigger dustbin more suitable for those who have pets and a large house.
  • Noise level. The S4 is a little bit noisier than the Roborock S6.
  • Charging dock. The new dock does not have infrared sensors. The Roborock S4 charging base is heavy and not easy to move, which provides a tight connection between the robot and dock.
The Roborock family: S4 vs. S5 vs. S6
Roborock S4, S5, and S6

The longest-lasting battery in the industry

The Roborock S4 is equipped with a 5,200 mAh battery (the biggest battery in the industry) and can run up to 180 minutes on one charge. It is an absolute winner in terms of battery life. Three hours of running on low power is insane. In my case, it has never been lower than 70% after cleaning. I live in a two-bedroom 70 sq.meter apartment and normally stick with Max mode, but keep in mind that Quiet mode saves battery life and is not as loud.

When the power is getting lower than 20%, the robot returns to the dock, recharges up to 80% and gets back to the point where it left off to finish the job. Once the bot has finished, it expertly returns to its dock to recharge. So, even if you have a really big house, it will not be a problem for the S4. I have to say, none of the Roborock cleaners I have tested have ever had an issue with finding the dock. Note that if you place the robot on the second floor, you have to do it with the dock, so the bot can find its way back home when finished.

Cleaning performance

The Roborock S4 is equipped with 12 types of sensors which help to navigate around without getting trapped or fall of stairs. This feature saves battery life if you have a mixed surface. 

The S4 new connectors that lead it to the charging dock
Charging contacts
The Roborock S4 wall sensor
The wall sensor

As with the previous models, the bot starts by passing along the edges of the area before moving to the rest of the room.

One thing to notice - reduced climbing ability. The Roborock S4 can cross a 15 mm (0.6 inches) obstacle when the Roborock S5/S6 climbs up to a 20 mm (0.79 inches) obstacle. The Roborock S4 might not be able to handle some thicker carpets, although it does not have issues with thin carpets/rugs.

The Roborock S4 new wheels and reduced climbing ability for better performance on thin carpets and bare flooring
The big wheels can cross an obstacle no taller than 15 mm (0.6 in)

The Roborock S4 has 2,000 Pa of suction power enough to lift AA batteries. If there are small things left on the floor, they will likely end up in the dustbin. Just remember to pick up small things and cords from the floor before running the robot.

The Roborock S4 is best suited for homes without carpets (or with thin carpets). Since it has strong suction and a brush with more bristles, the S4 does a good job on low-pile carpets and bare floors.

I have long hair and an easy maintain brush matters to me. I had problems with other robot vacuums because my hair tangled on the roller brush, and it was challenging to remove it. But I don't have this problem with the Roborock S4. Its brush is one of the best in the industry. The Roborock has an anti-tangle design and paired with strong suction, most of the hair goes straight into the dustbin while some stays wrapped around the brush. The hair gets clogged mostly on the edges where it can be removed easily.

The cleaning brush of the S4 with detachable tips ideal for pet owners and those with long hair
The cleaning brush with detachable parts

The Roborock S4’s pickup ability is one of the best in the industry either on low or high power settings as long as it is not on a thick carpet. It is good with hair, has strong suction and is ideal for allergy and asthma sufferers. 

The results are impressive. The Roborock fills out the bin every time it’s cleaning. I recommend cleaning the bin after every use. As for the filter, when it gets dusty, the suction power might not be as strong as when it's freshly-clean (based on our airflow measurements). I clean it every once in awhile, but there is no strict rule when it should be washed. It all depends on how sensitive you are to dust, whether you have pets, etc.

In general, the Roborock S4 is a great device for those who don't need mopping and don't have thick carpets but need a cleaner with efficient navigation that can get under most furniture and not leave a spot untouched.

Navigation & Mapping

The Roborock S6 has the most efficient navigation among other models in the family, and it seems like the S4 built is on the same platform. I have noticed that the S4 finishes cleaning faster than the Roborock S5 and spends about the same time (or even less) than the Roborock S6.

What makes the S4 faster than other robot vacuums? It understands room layout and builds a more effective lengthways path in long corridors and wide rooms, spending less time on turns. It is the same ability as seen in the Roborock S6, but I have never seen it in other robot vacuums.

To clean a 70 sq. meter apartment (~40 square meters area without furniture, etc.), the Roborock S5 spends ~43 min, the S6 ~37 min and the S4 ~34 min.

Roborock S5, S6, and S4: cleaning time compared
Roborock S5, S6, and S4: cleaning time compared

Check out the differences between the Roborock S4 and S6 in our video comparison:

An LDS sensor (laser distance sensor, also known as Lidar) is placed on the top of the device.

Its high-accuracy laser spins at 300 rpm as it scans the surrounding area. Data is then sent to a powerful ARM processor through a SLAM (simultaneous localization and mapping) algorithm to produce a 98% accurate layout of your house. This helps it know where to clean. As Lidar maps out the room, the robot does its chores while the powerful processor calculates the most effective z-shaped cleaning path. Mapping makes it handy to see any problem areas holding the bot back from navigating properly.

Roborock S4 LDS sensor on top of the lid
Lidar sensor on top of the robot

Keep in mind that the map will be saved only when the robot starts cleaning from the dock and returns by itself once it has finished.

As said before, the map is editable, meaning it can be tweaked to create separate zones and rooms, set no-go zones or send the robot off for cleaning a specific area with one simple tap on the screen.

If you don't like the way the robot recognizes your rooms, you can fix it by dividing or merging separate zones the way it should be.

The robot includes no less than 12 types of sensors, meaning this robot vacuum cleaner is more than capable of making it around your home with relative ease. The new Roborock cleaner rarely bumps into anything or gets stuck. The wall sensor helps it get very close (less than 2 cm) to walls or furniture without touching them.

The Roborock S4 is equipped with a revamped drivetrain, and it has the power to free itself from tight corners and furniture. Its reverse power is always stronger than its forward movement, which means the robot will most likely get out of tight spaces/traps, making the S4 more suitable for cluttered homes.

Noise level

The new model sounds a bit different: maybe it has something to do with the rubber side brush, but the S4 does not annoy me when working. It is not as quiet as the Roborock S6 but is noticeably quieter than the S5. On Max mode, it makes about 68 dB of noise while the S5 has ~70 dB.

A new Roborock app

Recently, Roborock released its new branded app for Android and iOS devices. The new app has almost the same features as the Mi Home app, but I like it more. It is faster and more convenient. It is worth mentioning that it receives updates with new additional features and bug fixes frequently. I like that Roborock decided to make a separate app. In my experience, the Mi Home app has lots of redundant functionality; however, it can be useful for those who use the Mi smart home ecosystem. The good thing is that the S4 can be connected with both apps, so you can choose which one suits your needs.

New Roborock app
The newest Roborock app screenshots

I was able to connect the Roborock S4 to my Android phone on the first attempt. The Roborock app scanned and recognized the robot vacuum and paired with it within a few seconds. Just make sure that your Wi-Fi router uses 2.4 GHz band since the S4 model doesn't work with 5 GHz band.

On the main screen, you can see the battery status, cleaning duration and cleaned area. You can choose between four different cleaning modes that change suction power depending on your needs. The robot is a little noisy, and the battery drains faster in turbo mode, but it provides deeper carpet cleaning thanks to the strong suction. If you are watching TV or don't want to be disturbed by the robot's noise, you can switch it to silent mode. In this mode, it makes minimal noise and can work up to 180 minutes on one charge. You can even sleep when it is running in silent mode.

Diving deeper, you will find more smart features such as setting zoned cleaning, restricted areas, intelligent rooms recognition, and so on. 

Another thing I like about the S4/S6 models - scheduling settings. Not only can you set the time of day for the bot to come out for a clean, but you can also choose which room it should tackle. It can be tweaked with various settings such as selecting the right suction level and when to repeat the cycle. Theoretically, you can send the Roborock to clean the kitchen at 10 AM and the living room at 2 PM if you don't want it to clean the whole place at one time.

Real-time tracking

The Roborock S4, as well as the S5 and S6 models, build maps and show them in the app in real-time. You can see the position and movement of the robot and where it has already cleaned in real-time. No matter where you are, as long as your phone connected to the internet, you can start the cleaning process and watch the robot vacuuming your place in real-time. It's a nice option to have, considering  that the two-times more expensive Roomba i7/s9 and Neato Botvac D7 display their created maps only when the cleaning done.

Virtual barriers and No-go zones

You can forbid the Roborock S4 to go through certain areas in your house. You can mark a part of your room as a No-go zone by drawing a rectangle on the map. Also, you can use virtual No-go lines (or barrier tapes) in a complex environment: they can be handy. This is a very useful addition if you don't want the robot to suck up your child's toys or disturb a pet's place. On the screenshot below you can see an example of how you can use the No-go lines and No-go zones.

No-go zones and No-go lines
No-go zones and No-go lines

Zoned cleaning

A zoned cleaning option lets you set a specific area that needs to be cleaned. I use this feature quite often, for example, when I have some messy places needing a quick cleaning. You can set the cleaning zones easily by drawing a rectangle on the map. there is also an option to set how many times the robot must clean the area (from 1 to 3 passes). You can see the screenshot I took during the cleaning process with three zones set up in different rooms.

Zoned cleaning
On the left: setting up three custom zones to clean. On the right: zoned cleaning in progress

Map management

Unlike the Roborock S5 that saves only one map, the newest S4 model can store two different maps (last one and backup) plus one with No-go zones saved. This feature will be handy for those with a two-story house. You can switch between saved maps in the "Restore map" menu.

Settings and map management
Settings and map management

Selected room cleaning

When I used the Roborock S4 for the first time, I was a little bit disappointed since there was no selected room cleaning option, which I loved so much in the Roborock S6. While I was writing this review, I got notification in the app that a new firmware is available to install. I was pleasantly surprised to see that this update brings the selected room cleaning to the Roborock S4!

Roborock S4 firmware upgrade

It gives me confidence that the Roborock S4 will grow with more smart features over its life. It means the S4 can recognize the layout of your house and automatically divide the map into separate rooms. The selected room cleaning allows choosing a certain room (or a few rooms) and sends the robot vacuum to clean it. 

Sure, you can use zoned cleaning for this purpose, as mentioned above, but the ability to just tap on the map to clean a specific room is much more convenient. At the moment, only a few robot vacuums on the market have intelligent room recognition. Moreover, Roborock implemented this feature in the best possible way: you can manually edit the map, merge or divide rooms if they were recognized incorrectly.

Merging and dividing rooms
Merging and dividing rooms

Cleaning history

The app shows the cleaning history. You will not only see cleaning logs, but also where the robot has been for a clearer picture of how it cleans. If it got stuck somewhere, you will see it in the history so you can  change that area by maybe setting restricted areas or physically fixing it. If the map is incomplete, restore previous maps and let the robot create a new one.

On the left: maintenance. On the right: cleaning history
On the left: maintenance. On the right: cleaning history

Smart Home integration

The Roborock S4 works with Amazon Alexa; you just need to install Roborock skills. Unfortunately, at this moment it is very limited: you can only start and stop the robot vacuum. It also supports Google Home: you can start/stop cleaning, ask if the robot is running or charging, send it to the dock, etc. Seems like it doesn't work with Google Home at the moment, but according to Roborock customer support, this feature will be added soon. If you paired the S4 with the Mi Home app, you could also use smart scenarios and automation to run the cleaner when a specific event happens in your smart home. I can’t wait when Roborock will add the ability to order the Roborock to clean a room by telling Alexa, for example, "Alexa, tell the Roborock to clean the kitchen" (as far as I know, Roborock team is already working on this feature).

Price & Where to buy the Roborock S4


Verdict: our thoughts about the Roborock S4

The newest Roborock S4 is one of my favorite robot vacuum cleaners. This automatic cleaner is an absolute winner in the price range. It provides the most efficient and intelligent navigation I have seen. It cleans my apartment faster than all the robots I've tested. I love the new design with the semi-transparent lid. The S4 is more than capable of providing impressive cleaning performance in homes with bare floors or thin carpets. It lacks a wet mopping feature, but it does have a revamped drivetrain. Roborock reduced the climbing ability of the robot to 1.5 cm, which means it is not suitable for thick carpets; instead, they increased the reverse power which is always stronger than its forward movement. Thanks to this, it has better maneuverability and the ability to free itself from tight places between furniture and corners in cluttered rooms not to mention a complex house environment. The newest Roborock app feels sleeker, faster and more stable than the Mi Home app. I highly recommend the Roborock S4 for those who live in a home without carpets (or with thin low-pile carpets). The cleaner has a larger dustbin than its predecessors and an easy-to-maintain roller brush, so pet owners will be happy with it as well. The robot costs less than other big-name brand competitors.

Against

The Roborock S4 is not suitable for middle/high-pile carpets. Most likely it will not be able to cross a carpet thicker than 1.5cm (0.6 inches). If you are looking for a robot vacuum with a mopping feature, you had better take a look at the Roborock S6.


Comments ()

  1. Lily
    #      +2
    Is it better than the Roborock S5?
    reply   
    1. Natalie Red
      #      +1
      Hey Lily :)

      It depends on what you want the robot vacuum for. The S5 has mopping while the S4 does not have this option.

      To me, the selected room cleaning feature is something I love the Roborock S6 and S4 for. You can also use zoned cleaning if you want the robot to go clean a certain room but to me, taping on the room is more convenient than drawing a rectangle.

      If you live ina very big house, the S4 is more suitable because of the longer runtime.

      If you own a multi-story house, the S4 is right for you since the S5 saves one created map only.

      On the other hand, if you have thick carpets, the Roborock S4 would not be ideal in your case. It was not designed for homes with thicker carpets.

      A bigger dustbin and detachable cleaning brush are the things to think of before buying the right one. If you have long hair or pets, the S4 is better because of the container that holds more debris and cleaning brush that has removable tips for easy maintenance.

      Design. I personally love the new design. It looks so unique and fresh that I would get the S4 only for the way it looks :)

      Keep in mind, the Roborock S4 is cheaper so if you don't need extra features such as mopping and there are no thick carpets in your place, I would recommend going with the Roborock S4.
      reply   
    2. Matthew
      #      +2
      Thoughts on this versus the Mijia 1S? Know it has a larger dustbin, and you don't have to «live in China» to be able to use it. But the Mijia does keep a higher obstacle clearance and has VSLAM.
      reply   
      1. Natalie Red
        (edited})
        #      +1
        Hi Matthew. Either the S4 and MiJia 1S has the same 15 mm (0.6 in) clearance.

        So the difference between the Roborock S4 vs. Xiaomi MiJia 1S:

        1. As you pointed out, the S4 has a bigger dustbin which is good if you have a big place, pets, etc.
        2. HEPA filter. The Roborock S4 is equipped with a filter that can be washed with water. When the filter is clean, suction is stronger. Plus, washable filters meant to last longer.
        3. Cleaning brush. The Roborock S4 has a roller that has removable tips while the Xiaomi brush is solid. Does make a difference in terms of maintaining long human hair and pet hair.
        4. Smart Voice assistant integration. The Roborock S4 supports both: Amazon Alexa and Google Home. As far as I know, the Xiaomi MiJia 1S is not compatible with them (not sure though since there are only a few articles about the MiJia).
        5. The MiJia is equipped with a visual sensor that is claimed to be able to recognize rooms. The Roborock S4 does not have a visual sensor but it also supports room recognition. Other than that, I did not find info of why the additional visual sensor is better than Lidar only. If you are worried about privacy, the robot with a visual sensor might not be for you.
        6. The Roborock S4 supports the Mi Home and Roborock app. The Xiaomi only can be connected to the Mi Home.

        I would recommend the Roborock S4, it does cost a bit more but it also has more advantages compared to the MiJia 1S. Don't get me wrong, the Xiaomi is also a decent player on the market, but compared to the Roborock S4, it can not beat the beast.
        reply   
      2. Josh
        #      +1
        I was about to get the Roborock S5. Does the mopping feature worth it or better buy the S4 instead?

        reply   
        1. Natalie Red
          #      +1
          The mopping feature in the Roborock S5 might not be the best in the industry but it is able to keep the floors clean if the robot mops a few times a week. Though it will not replace actual mopping.

          It depends on your needs, if you really want mopping, go with the Roborock S5 but it lacks some smart features the S4 is equipped with but if the mopping is not in the first place, consider maybe getting the Roborock S4.
          reply   
        2. P
          #      +1
          Does it require internet to use the app and control the S4? Since mapping happens locally, can I keep it on a separate vlan and only work with it locally? Presumably after firmware/updates are completed.

          Thanks
          reply   
          1. Michael Fisher
            #      0
            Unfortunately, you can't use the app without an internet connection. It sends a request to Roborock's servers every time you perform any operation with the app.
            reply   

          Share via: