One challenging task for most robot vacuums is their ability to clean large quantities of debris with efficiency. The
Amazing Performance, Efficient Cleaning But at a Premium Cost
Roomba S9+ Review
When iRobot launched the S9 a few years back, it was a complete redesign from the ground up. Not only did it have a new frame, but most of the design elements from previous Roombas are scrapped to prioritize cleaning performance. Every aspect of this robot focuses on efficiency, from the wide extractors to the clean base station, and test results reveal that to be the case. However, there are issues with the S9 that you’ll see as you read along with this review, so whether this robot will be worth it or not will depend on whether you can live with the deficiencies.
- Insanely high-end airflow (25 CFM) makes this the best performing robot vacuum (to date)
- Empties the dustbin for you
- Wide extractors enable it to pick up more debris per pass
- The dustbin is easy to empty thanks to the wide opening
- Decent dirt capacity (500 ml) – in case you opt for the S9 variant without the clean base station
- Insanely expensive
- The app doesn’t offer the best user experience (lacking several features)
- It relies on a light source (not optimal to use in dark conditions)
- 1 Amazing Performance, Efficient Cleaning But at a Premium Cost
- 2 Introduction to the iRobot Roomba S9+
- 3 How does the Roomba S9+ navigate?
- 4 App features
- 5 How much power does the Roomba S9+ have?
- 6 Cleaning performance
- 7 How long will the Roomba S9 run?
- 8 How noisy is the Roomba S9+?
- 9 What comes in the box?
- 10 Parts availability
- 11 Maintenance
- 12 Product Specifications
- 13 Where can I buy the Roomba S9?
- 14 Is the Roomba S9+ worth it?
- 15 The Verdict: Outstanding Cleaning Performance, Crazy Expensive
Introduction to the iRobot
iRobot pioneered self-emptying robot vacuums when they introduced the I7, and with the S9, they’ve taken it to a whole new level in terms of performance.
Let’s go through the upgrades iRobot put in the S9.
1. New Shape
Unlike previous Roomba iterations, the S9 now has a D-shaped frame, similar to the Neato Botvac series. I don’t know why iRobot made the change, but one thing is for sure – these changes all are functional and contribute to this variant being the best in its class when it comes to cleaning floors.
2. Wide extractors
Changing the design framework enabled iRobot to fit in broader extractors. It’s wider than nearly all other brands, except for the Neato Botvac at 9.5 inches. The S9 still utilizes the same rubber extractors as the I6/I7, only longer.
These broad extractors improved the S9’s efficiency two-fold over the Roomba I6, and the result is cleaner passes with zero debris particles between rows.
It’s wider than any other robot vacuums I’ve tested, except for the Neato Botvac.
Take a look at the size difference between the
The size disparity is apparent in this side-by-side photo.
3. Redesigned side brush
Relocating the primary rollers also necessitated a change with the side brush. The new design has a smaller diameter but with two more prongs.
It doesn’t spin as fast as earlier Roomba models; hence it won’t scatter as much debris.
Its primary function is grabbing dirt at the edges and dragging them towards the main brush since it isn’t flush to the sides. iRobot calls this perfect edge technology, and tests (at least my experiments) reveal that it works! More on that here.
4. A larger top-mounted dustbin
All current-generation Roomba models before the S9 utilized a rear-mounted dustbin. iRobot changed things up with the S9 by moving it towards the top. The relocation improved usability as it is easier to remove with the built-in handle.
Another upgrade is the capacity, which is 25% more than the I6/I7 (400 vs. 500 ml).
Dirt volume won’t be an issue with the clean base station, but it can be without it, so it’s something to point out.
It has a bigger HEPA filter with easier access from the top.
The wide opening makes it easier to empty and clean. Since the motor is not inside the container, the whole assembly is washable if it gets too mucked up.
5. Bigger port (for clean base station)
The S9 has a larger port where a second vacuum in the clean base station uses to suck out contents from the robot’s dustbin. It does an excellent job at clearing contents from the dust container, even hair particles.
What the difference between the
Roomba S9 and S9+?
There are two S9 options – the S9+ (with the clean base station and the S9 (w/o the auto-empty feature) at least on Amazon.
Opting for the “plus” version is more expensive since it has a self-emptying feature, where a second vacuum inside the dock cleans the robot’s dustbin after every run.
But only the S9+ is available on the iRobot website. My choice would be the plus version, obviously to enjoy the auto-empty benefits.
Clean base station
The iRobot design is one of the best I’ve seen because of its simplicity. It’s a single piece, so expect it to hold up well over the long term, and I like that consumers will have a lot of options with where they purchase bags. iRobot sells bags, but a lot of third-party brands sell them as well at a cheaper cost.
You can place it on hard floors or carpets without worrying about any alignment issues since the port connecting the dustbin to the base station is underneath the robot.
While iRobot doesn’t specify the capacity, I’m guessing it’s close to 2.5 liters since the S9 bags are close in size to another brand, the Yeedi Vac Station.
The I6/I7 and S9 bags are identical, so you can’t find S9 specific ones; the I6 versions will fit just fine.
Starting with the I7, iRobot VSLAM to their premium robot vacuum line, and it’s the same technology used in the S9.
VSLAM or Visual SLAM combines a top-mounted camera and SLAM, giving this robot enough smarts to navigate efficiently.
Like its LIDAR-based counterparts, it can move in straight lines, clean specific rooms or zones, and pinpoint its location with the aid of an optical sensor underneath.
But the use of a camera sensor has its limitations. If you’ve done any photography stuff, you’ll quickly realize that the difference between a good and great photo can boil down to lighting.
With VSLAM, that’s also the case. The S9’s top-mounted camera needs light to function. It definitely a must-have for drawing maps during the initial run, and iRobot specifies it in the app.
While it can function without light thanks to the optical sensor, it won’t work as well, increasing the risk of not completing the task.
It doesn’t need a very bright room to function, but it needs a decent amount of light to navigate efficiently.
I noticed that iRobot has dialed back the aggressiveness, at least for their premium line (I6, I7, S9), and it doesn’t bump into furniture as hard.
It also did well avoiding getting wedge between narrow furniture legs like this office chair, navigating through this maze well.
However, it isn’t as efficient or as decisive as a LIDAR robot (Roborock, Neato) in this aspect.
One plus with a camera-based sensor is the lower profile. Without the LIDAR cover, the S9 fits under lower profile furniture better (under 3.2″) than a Roborock, Dreame, or any robot with a top-mounted laser.
1. Map saving
One of my favorite features with the iRobot app is its map saving feature with the option to save up to ten levels. It’s six more than Roborock and eight more than Ecovacs. In each map, users can add multiple so-called “clean zones” and “keep out zones.”
2. Keep out zones
iRobot’s version of the no-go zones, where users can draw boxes or rectangles to indicate off-limit areas to the robot, so it doesn’t wander to places it shouldn’t.
It’s something that most brands incorporate into their products. According to this article on the iRobot website, there’s no limit to how many zones you’ll draw, but keep in mind that adding too much may hamper navigation.
Unfortunately, the iRobot app doesn’t have access to the invisible wall, so there’s no way of drawing diagonal lines. In most cases, keep out zones are enough for most tasks, unless your home has a complex layout.
3. Clean zones
Opposite to keep out zones is clean zones. Instead of identifying off-limit areas, clean zones provide quick access to areas that may need more frequent vacuuming.
I like that you can name these areas accordingly to avoid confusion when accessing it through other parts of the app.
4. Room naming
Another convenience feature I’d like to highlight is room naming. After the robot successfully creates the map, you can now add dividers to mark partitions between rooms, select a name from a list, or use a custom name.
The neat part of this feature is it’s usable with a device like Alexa. So you can say, “Roomba, clean Benjamin’s room,” and it will clean that area.
5. Selective room cleaning
Once you’ve set dividers and name rooms, another feature is unlocked – selective room cleaning.
There are several options. Using Alexa or tapping the “new job” icon on the upper right and check all the areas you want to be cleaned.
The iRobot app also has a scheduling feature where users can automate the cleaning schedule. One difference with premium Roomba options (I6/I7/S9) versus random navigating options (600 and E-series) is users can schedule multiple runs per day with a minimum three-hour interval between runs.
I’m not sure why iRobot added these intervals. I guess it’s because of the shorter run time to give it ample time to recharge.
7. No live map
Unfortunately, the iRobot app doesn’t have any live maps. So users can see where the robot is in real-time.
It’s been a few years since iRobot released the S9, and I’m not sure if they’ll ever add this feature, perhaps in a newer model, when they release it.
8. Robot settings
There isn’t much here aside from adjusting the robot’s power setting. You’ll have these options.
- Detailed clean: a little more thorough, with the power at the middle setting. Great for cleaning carpet or if you need a more meticulous clean.
- Quiet clean: prioritizes low noise operation and run time since it uses the lowest power setting.
- Custom: This allows users to customize power and cleaning passes to suit their needs. Increasing power will drastically reduce run time. Max power will only yield around 45-minutes worth of usage and a max of 75-minutes at the lowest setting.
How much power does the
Roomba S9+ have?
iRobot doesn’t specify official suction figures with any of their products, while other brands like Roborock use Pascals as a unit of measure. For all robot vacuums I test, I use an anemometer to measure airflow going through the main nozzle (or brush).
Here are the complete results in all the power settings.
- Low: 11.33 CFM
- Mid: 14.52 CFM
- Max: 25 CFM
Combining the high airflow and wide extractors results in an efficient cleaning robot, which we’ll look at in detail next.
The high airflow manifests itself with excellent scores as the S9 picked up some of the highest across the board.
I use coffee grounds, quaker oats, quinoa, pet litter, sand, hair, and fruit loops to check how well the S9 will pick these up.
Here are the overall scores
- Overall: 97.93%
- Hard floor: 99.5%
- Sand on hard floor: 100%
- Carpet: 99.25%
- Deep cleaning: 93%
Cleaning performance is superb with excellent pick up in all categories. You can see the high airflow and agitation in play here, and the eye test confirms these scores at it had the cleanest pick-up.
Hard floor results
- Quaker oats: 100%
- Coffee grounds: 99.2%
- Quinoa: 100%
- Pet litter: 98.8%
No issues with hard floor pick-up as the S9 had an excellent average of 99.3%. It did worst with heavy quinoa, but one reason for the sub-99% score is the side brush scattering some of it.
Sand on hard floor
One of the toughest debris to pick up on hard floors is sand. For this experiment, I use 50 grams worth of it.
Some would say it’s an unreasonable test, but it’s a good barometer to how a robot vacuum would fare cleaning this debris type in areas with such.
Even with the middle setting, the dropoff isn’t significant at 99.2%.
Hair wrap test
Next, we’ll look at how the rubber extractors fare against hair strands five and seven inches. I used more than a gram for each test to see how well these rollers will resist tangles.
- 5-inch: 81% in the dustbin; 19% on the rollers
- 7-inch: 82% in the dustbin; 18% on the rollers
Nothing wrapped on the extractors after the five-inch test, but most of it was on the roller’s right axle.
Some strands were wrapping on the light green roller with the seven-inch test and some on the axle.
One advantage of a bristle-less design is that it is easier to remove hair wraps without using scissors.
The strands on the axles easily come off, but it’s an area to check continually as part of the maintenance cycle to keep it functioning at an optimal level.
The S9’s D-shape is optimal for cleaning edges, and the results don’t lie. It picked up nearly every crumb on this test area and most on the quaker-inch crevice.
Low pile results
- Quaker oats: 100%
- Coffee grounds: 96.6%
- Quinoa: 100%
- Pet litter: 100%
Again, excellent scores all around. It did worst with coffee grounds, but still a tidy 96.6%, better than most robot vacuums that score close to 90%.
Mid pile results
- Quaker oats: 99.2%
- Coffee grounds: 98.2%
- Quinoa: 100%
- Pet litter: 100%
Superb pick-up on mid-pile carpet. Surprisingly, it did better picking up coffee grounds on this surface. Not sure why. It could be a random thing where it navigated over the area enough times to pick up a higher percentage. But it’s another proof of the high airflow.
Next, we’ll look at deep cleaning results where I rubbed 100 grams of sand on mid-pile carpet. Cleaning embedded debris is a tough ask for most robot vacuums as these machines lack airflow and agitation to pick up debris under carpet strands.
One telltale sign of the high airflow is the absence of build-up on the brush roll assembly. I would check this area for any accumulation after experiments like these to see the robot’s effectiveness at gobbling up dirt towards the dust container.
With the S9, there’s no loose accumulation which a good sign.
How long will the
Roomba S9 run?
One downside to using a high-powered motor and twin brush is the amount of current it consumes. The added juice cuts through the run time, and the S9 will run for only 75 minutes at the lowest setting.
Using the max setting will cut it down further to 45 minutes. The middle setting will be somewhere in between – around 50 to 60 minutes.
Fortunately, this robot has recharge and resume – it resumes cleaning after recharging to the area it left previously.
The clean base station further adds to the autonomy as it empties the robot’s dustbin after it docks to recharge.
How noisy is the
One downside with the S9’s powerful motor is its high noise levels. I used a sound meter to check how much noise it makes and here are the results.
- Low: 66.3 dB
- Mid: 68.5 dB
- Max: 74.1 dB
What comes in the box?
Roomba S9robot vacuum
- Clean base station with plug – one bag inside (110-volts)
- One extra bag
- One extra side brush
- User manual and quick start guide
One advantage of purchasing a Roomba is the sheer availability of parts. For the S9, there won’t be a shortage of replacement components. You can purchase parts like the side brush, extractors, filter from third-party brands at a lower cost. Even bags are abundant since the S9 uses the same bag as the more popular I6/I7 variants.
As with all robot vacuums, the S9 needs upkeep to maintain optimal performance for years. If you’re spending this much, it makes sense to lengthen its service life as long as possible, and I’ll give you some tips for it. I’ve published a comprehensive guide on cleaning the
- Extractors: These two rollers receive the most abuse as it’s the robot’s primary tool for debris pick up. Dirt and dust will accumulate on it and the axles. Check it at least once a week (twice if you have lots of pets) to clean out the build-up, especially on the axles.
- Side brush: Another area where hair accumulates. Do a visual check once a week for hair build-up on the prongs or base.
- Dustbin and filter: The clean base station automates the task of emptying the dustbin. But check it at least once a month if it needs a thorough clean. This component is washable, but the filter isn’t since it’s laced with paper material. One way of extending the filter’s service life is tapping it on a solid surface to dislodge dirt trapped on the folds. Replace once every two to three months to maintain performance.
- Caster wheel: This is the small wheel behind the robot. Dirt will stick on the surface and the areas under it. Pull it out and wipe with a clean, dry microfiber cloth.
- Side wheels: Similar to cleaning caster wheels, contaminants will stick on them. Clean it twice a month with a clean cloth.
- Bag inside the clean base station: Dispose of the bag once it’s full, and the iRobot app will notify users of it.
- Clean base station: There’s not much here. Only keep the port going to the bag free from any obstacles.
|Battery||3600 mAh Li-ion|
|Run time||Up to 75 mins.|
|Auto empty capacity||2.5-liters|
|Dirt Capacity (dry)||500 ml.|
|Recharge and Resume||Yes|
Where can I buy the
You can buy the
Disclaimer: I will earn a commission if you purchase through any of the links above, but at no extra cost to you, so it’s a win-win for us!
Roomba S9+ worth it?
Consumers who would want to enjoy the benefits of the
If it’s a need, especially for folks with wall-to-wall carpeting, then the
5 Reasons to buy the
- Outstanding cleaning performance: The
Roomba S9is the best cleaning robot vacuum I’ve tested so far, bar none. Only the Roomba 980 comes close to it, but that variant doesn’t have the containment and map-saving features present in the S9.
- Auto-empty convenience: The clean base station adds a convenience wrinkle of emptying the robot’s dustbin for you. So there’s no need to do this task manually.
- Map saving & smart navigation: This model has iRobot’s latest navigation technology – imprint smart mapping. Users can save maps, add containment, and select rooms to clean.
- Great on carpet: If carpet cleaning is a top priority, then the S9 should be on your shortlist as it picked up 93% in deep cleaning tests.
- Wide extractors: The wide cleaning path makes the S9 efficient at debris pick up.
The Verdict: Outstanding Cleaning Performance, Crazy Expensive
After testing this robot extensively the past few days, the
It scored the highest across the board in both surface and deep cleaning experiments.
Ane while cleaning performance is outstanding, it is incredibly costly. This model is one of the most expensive alternatives, and there are some limitations with functionality, particularly the app.
Run time is also compromised with the powerful motor, and it won’t run as long as its top competitors.
But with recharge and resume, this shouldn’t be a sticking point. If you can live with its app limitations and high cost, but prioritize cleaning performance, then the S9 is the best out there for the task.
Roomba S9+: Amazing Performance, Efficient Cleaning, But Crazy Expensive
Navigation - 94%
Surface Cleaning - 99.58%
Deep Cleaning - 93%
Quality - 97%
Design - 96%
Value - 93%
The Roomba S9+ is one of the best (if not the best) cleaning robot vacuums available. Based on tests, it scored the highest overall cleaning performance score. Eye tests validate these figures as the S9 picked up debris cleanly on hard floors and carpets. But there are some drawbacks to this product, namely the shorter run time, lack of certain app features, and the extremely high cost. If you don’t mind paying a premium for a robot vacuum that will clean your floors well and not mind the issues, then the S9+ is worth considering.