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Roomba i3+ vs s9 (2021): Which Robot Vacuum Cleaner Is Better?

With the Roomba i3+, iRobot is making robot vacuum cleaners even more accessible to most households. The budget-friendly machine shares the same three-stage cleaning system as its higher-priced siblings, and packs a couple of smart features for added convenience. However, as with any affordable alternative, the i3+ does make some compromises, especially when compared to more premium robovacs like the Roomba s9. But do these concessions give the S9 a clear advantage? Below, we compare the Roomba i3+ and Roomba S9 to see which robot vacuum cleaner is a better deal.

Roomba i3+ vs S9 Comparison Chart

ModelRoomba i3+Roomba s9
 Amazon productAmazon product
PriceAmazon productAmazon product
Suction Power10x suction power compared to Roomba 600 series40x suction power compared to Roomba 600 series
Smart MappingNoYes
Smart NavigationYesYes
Cleaning SystemPremium 3-stage cleaning systemPremium 3-stage cleaning system
Tangle Resistant BrushesYesYes
Clean Base Automatic Dirt DisposalYesNo
Create Keep Out ZonesNoYes
High Efficiency FiltersYesYes
Imprint LinkYes, with Braava jet m6 robot mopYes, with Braava jet m6 robot mop
Voice Assistant Alexa and Google AssistantAlexa and Google Assistant
Dimensions13.26โ€ณ x 3.63โ€ณ12.25″ x 3.5″
Weight7.44 lbs8.15 lbs


The Roomba i3+ comes in a round form while the Roomba s9 follows a D-shaped design.

The Roomba s9’s (right) PerfectEdge gives it a distinct form that departs from the typical round design like on the Roomba i3+ (left)

Before the Roomba s9, iRobot’s vacuum cleaners all came in the same puck-shaped form that’s been emblematic of the brand for a few decades now. The Roomba i3+ carries this same design DNA. It’s a nifty, circular robovac with discreet physical buttons on top, and an advanced cleaning system underneath.

In addition, the controls are unobtrusive and feel integrated into the vacuum cleaner’s body, making issues with dust entering the mechanism minimal. Surrounding the i3+ is a black, plastic bumper. Meanwhile, the robovac’s core itself comes in textured-looking, gray finish. It’s a simple design that shouldn’t look out of place in your home.

The Roomba s9, on the other hand, is a bit of departure from iRobot’s lineup of robot vacuum cleaners. Instead of a round machine, you get a D-shaped cleaner โ€” a combination of a square front and a circular back. It’s not a radical innovation from iRobot but a lesson learned from rival Neato’s own brand of robot vacuums.

However, the s9 does offer a more refined finish that lends the machine a unibody look. The D-shape is largely geared towards better edge cleaning but also makes a case for a more premium-looking cleaner. And the s9 does look pricier, with its copper-colored disk at the center and a matte, charcoal black body that serves for contrast and better dirt-resistance.

Cleaning System

The Roomba s9 offers a more comprehensive clean although the i3+ does come with a Clean Base for automatic dirt disposal.

Here’s a look at the cleaning system underneath these robot vacuum cleaners.

Compared to iRobot’s best-selling 600 series, the Roomba s9 and i3+ offer about 40x and 10x more suctioning power respectively. The s9 also comes with power boost technology that automatically increases suction to draw in deep-seated dirt, debris, and particles from carpets and rugs.

Both vacuum cleaners do sport the same 3-stage cleaning system from iRobot. This includes iRobot’s unique tangle-resistant dual multi-surface rubber brushes โ€” with one brush loosening dirt, while the other extracts the particles and pulls them in. But when it comes to cleaning corners and edges, the Roomba i3+ and s9 use different mechanisms.

On the i3+, you get edge sweeping brushes that help eliminate debris along walls and, as expected, edges. However, because of the vacuum’s round design, it’s not capable of hugging walls and reaching trickier corners of a room.

This is where the new shape of the s9 works its magic. Called PerfectEdge technology by Roomba, the squarish front half of the Roomba s9 fits better in 90-degree areas. This edge also comes with specially designed corner-sweeping brushes that boast of five arms and a 26-degree angle to grab dirt and debris where the i3+ may struggle.

Nonetheless, Roomba’s budget-friendly i3+ model does come with a Clean Base automatic dirt disposal system. It certainly makes cleaning up easier, as the AllergenLock bags can hold dirt sucked by your Roomba for up to 60 days. With the s9, you’ll need to purchase the base separately.


iRobot’s Roomba s9 is equipped with a more advanced navigation system compared to the i3+.

The Roomba i3+ can recharge and resume on its own while the s9 can learn the layout of your home.

The Roomba i3+ and s9 are both equipped with smart navigation. Using advanced sensors, these robot vacuum cleaners can maneuver inside your home and clean it following neat rows. Moreover, both robovacs can automatically detect which area of the house is the dirtiest, and put extra effort in cleaning this zone.

On the Roomba i3+, a reactive sensor technology ensures the vacuum avoids obstacles and obstructions. This should translate to a robovac that’s less likely to get stuck under the sofa or other furniture. However, you only get a regular mapping feature on the i3+. This means that while it will map your home, it’s only good for any cleaning that’s in progress.

With the Roomba s9, you get vSLAM technology. Through this advanced mapping feature, the s9 not only maps out your space for cleaning but also learns the layout of your home and keep it in its memory. As a result, you get a robovac that understands its local environment, and carry out cleaning routines more efficiently.

An added benefit of the smart mapping feature on the Roomba s9 is what iRobot calls Keep Out Zones. In tandem with the layout created by your robovac, you can add rectangular zones to your home’s map which the s9 will ‘keep out’ of. This means you don’t have to worry about your robovac working in a room of fragile furniture or equipment.

Smart Features

Both robovacs can be managed through the enhanced iRobot Home app.

iRobot’s advanced robovacs work with voice assistants and with its fellow smart cleaning appliances.

These days, your smart appliance is only as good as its accompanying mobile application. Thankfully, iRobot has updated their Home app to the latest platform called Genius. As mentioned earlier, the iRobot Home app allows users to create Keep Out Zones for the Roomba s9. In addition, the app can be used for event-based automations, including ideal cleaning schedules for both the Roomba i3+ and s9.

Apart from pre-set cleaning routines, the iRobot Home app will also recommend cleaning schedules based on a user’s cleaning habits. The application also comes with Imprint link, so you can sequence cleaning between a Roomba vacuum cleaner and Braava robot mop. Just like most smart devices, the Roomba i3+ and s9 are also compatible with Amazon Alexa and Google Assistant. With this feature, you can carry out voice commands to start vacuum cleaning, end routines, and โ€” on the s9 โ€” direct the robovac to clean specific areas of your house.


The Roomba i3+ is a solid, budget-friendly robot vacuum cleaner. But if you have the money, then the Roomba s9 is the better investment.

Amazon product

With its three-stage cleaning system and accompanying Clean Base for automatic dirt disposal, the Roomba i3+ is a strong entry-level option for anyone who wants to try out a robot vacuum cleaner. The model builds on the core features of many favorite iRobot models while coming in at a more affordable price range. Of course, this means cutting corners in terms of navigation and a few smart features. But overall, this is a solid robot vacuum cleaner for any household.

For those who like the convenience of letting the robovac do its job, then the more premium Roomba s9 is a better option. It certainly costs more than the i3+, and you’ll need to purchase the clean base separately, too. However, its powerful suction and smart mapping features makes this a largely independent smart device that can clean wherever and whenever you want it. Plus, it’s unique design gives it a sure advantage of eliminating dirt and debris in tough-to-reach corners. If you have deep pockets, then this top-of-the-line robot vacuum cleaner is worth getting.


๐Ÿ“Œ What’s the runtime of the Roomba i3+ and s9?

In terms of battery life, the Roomba s9 has the edge. Although slightly smaller and thinner than the i3+, the s9 comes with a larger battery that delivers about two hours of runtime. In contrast, iRobot’s new budget model clocks in at about 75 minutes of battery life.

๐Ÿ“Œ Does the Roomba s9 come with a Clean Base Automatic Dirt Disposal?

No, it doesn’t. To get the Clean Base Automatic Dirt Disposal, you’ll have to get the Roomba s9+ option.

๐Ÿ“Œ Is there a difference between the multi-surface brushes of the Roomba 600 series and the Roomba s9?

The Roomba s9’s dual surface brushes are 30% wider compared to those on the 600 series robot vacuum cleaners.

๐Ÿ“Œ Can the Roomba i3+ recharge and resume cleaning on its own?

Yes, the Roomba i3+ can automatically go back to its charging base on its own, and once fully charged, resume cleaning where it left.

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Mari Bassig

Senior Editor, writer and researcher passionate about gadgets, social media, and music.