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iRobot Roomba Combo j9+ review: The best Roomba robot vacuum and mop yet

Our Rating :
£1,149.00 from
Price when reviewed : £1249
inc VAT

The cream of iRobot’s Roomba range makes a good job at both cleaning and mopping, while needing far less emptying


  • Superior object avoidance
  • Easy to use
  • Decent all-round cleaning


  • Expensive
  • Lacks mop rinsing
  • Struggled with flour spills during testing

iRobot has always followed its own path when it comes to robot vacuum cleaner design, and the iRobot Roomba Combo j9+ is no different. However, while the j9+ continues to fly the flag for iRobot’s unique features, which include superior object avoidance and navigation without the need for a LiDAR turret, it also plays catch-up with regards to some of the better features we see in rival models.

Buy the full Combo j9+ package and you’ll end up the proud owner of a robot that combines both vacuum and mop functions, and comes with a base station that both stores water for refills and empties the collection bin into a large bag. This all adds up to a labour-saving device that reduces your input even further.

iRobot Roomba Combo j9+ review: What do you get for the money?

The iRobot Roomba Combo j9+ looks almost identical to the Roomba Combo j7+, with the outside casing differing only in the colour of the metallic-effect plate on the top. It’s the same size, at 310 x 400 x 337mm (WDH); however, a difference in weight (4.07kg rather than 3.33kg) suggests a change to the internals.

First, there appears to be an increase in suction power. iRobot doesn’t quote its suction power in kPa, except in relation to previous models of Roomba, but it would appear from the specs and our test results that there’s definitely an uplift in this robot’s suction capability.

The Combo j9+ also comes with a more sophisticated base station, which features a classy-looking (albeit fake) wooden top. The main difference in terms of features is that the base station here has its own water tank, which keeps the water in the robot’s mopping reservoir topped up. We’ve seen plenty of robot vacs with self-emptying capabilities and mops with water tanks, but having both in a single unit remains relatively unique, limited only to the Ecovacs Deebot X1 Omni.

Elsewhere, it’s all familiar. The lack of a LiDAR turret allows the puck-shaped robot to manoeuvre under lower items of furniture better than most of its rivals. In addition, the mopping pad is attached to a plate on the end of an extending arm, so the robot can automatically lift it out of the way when it isn’t in use.

On the underside you’ll find iRobot’s standard two distinctive green rubber-jacketed rollers, which rotate in opposite directions to encourage dirt into the suction port. There’s also a single sweeper brush on the right that reaches beyond the edge of the robot, and is designed to flick dust and dirt into the vacuum’s path as it travels.

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iRobot Roomba Combo j9+ review: What is it like to use?

iRobot has been making robot vacuum cleaners for long enough to have the setup process down to a fine art. The Roomba Combo j9+ comes with a clear, illustrated setup guide to get you from plugging in the base station to connecting to your Wi-Fi, so you can control the robot vacuum via the iRobot app.

The app is easy to use and leverages the same base software across the entire iRobot range, with different features added or removed where different models offer varying abilities. It’s generally well laid out and simple to operate.

To start, the robot creates an internal map using a reasonably quick mapping run, with new areas easily added in the future if you don’t manage to access every room on the first run. As mentioned, the j9+ doesn’t come with LiDAR, so it won’t be possible to easily add no-go areas as it maps; but they’re simple enough to drop in later.

It’s here that my main criticism lies. The Roomba’s app still doesn’t display its location as it cleans. While this might not be a deal-breaking omission, it’s a feature I have welcomed in the apps of rival models, particularly those that can locate themselves with certainty as a result of their LiDAR navigation.

The benefit of the above, something that Roomba users are missing out on, is that you can see at a glance how much of its cleaning mission a robot has completed, and how much is left. Nip off to do something else while the Roomba is in action, and you can be left wondering which rooms have been tackled and how much longer the robot might be before it’s finished cleaning.

However, this is my only criticism; the rest of the app is a joy. It’s easy to adjust the map, set up scheduled cleans, add favourites (such as a quick clean of the kitchen or under the dining room table), adjust the settings for individual areas and browse through the cleaner’s history.

With the Roomba Combo j9+, the history is more pertinent than most, because it ties in with the robot’s classy object avoidance system. If it encounters something unusual on the floor, it will circumnavigate it as close as it dares and capture a photo, which will turn up in the app for you to check. If it’s a temporary obstacle, such as a rogue sock, then you can mark it as such. Pick it up and let the Roomba know once you’ve done it, and the j9+ will pop back out and give that area the once over.

Optionally, you can also add the data to iRobot’s dropped object database, which will help the system learn and develop – as long as you don’t mind iRobot keeping a visual record of your mess.

When the robot has completed cleaning and has returned to the base station, its collection bin is emptied into a disposable bag that sits within the base station. This offers enough capacity to empty the collection bin 30 times. There are two bags in the box to get you started, and iRobot sells replacements for £9.99 each or £22 for three. They’re the same bags as used in other iRobot systems, though, with plenty of third-party alternatives available for much less.

The base station is also capable of refilling the mop from a water tank, which iRobot claims will hold enough water to keep the robot topped up for 60 days – though, clearly, this is dependent on the number of times you mop. What it doesn’t do is rinse the mopping pads, a job you’ll need to do yourself. There are two pads provided and they can be cleaned in the washing machine. New pads cost £40; but, again, third-party alternatives are available for a lot less.

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iRobot Roomba Combo j9+ review: Is it good at finding its way around?

Considering it doesn’t use LiDAR for navigation, nor display a live map in its app, the iRobot Roomba Combo j9+ is a decent navigator. We experienced no issues with the robot getting to any area we requested, nor it returning to its base station. It’s also perfectly happy to operate with more than one map, if you live in a house of more than one storey.

The j9+ isn’t quite as fast at covering a large area as LiDAR-equipped models, as you can see from the chart below. The Eufy, Ecovacs and Ezviz robot vacuums all come with LiDAR and shave a few seconds off the time it takes to cover each square metre. However, the Roomba remains a lot faster than the Dyson Vis Nav 360, which is so powerful it drains its own battery and has to keep returning home for a recharge.

irobot roomba combo j9+ review 2024We tested the robot around some particular hazards that have been known to stop lesser robots in the past, including thin doormats prone to curling up, thick thresholds between rooms and the legs of occasional tables. Happily, the j9+ traversed them all perfectly.

Where the robot particularly shone is with its object detection and avoidance. We tested this with a trio of hazards – a dropped sock, a smartphone charging cable and a convincing fake pet poo. The Roomba Combo j9+ successfully detected, identified and avoided them all, sending photos of each hazard to the app for confirmation.

However, where the j9+ didn’t fare too well is for avoiding chair and table legs, choosing to bump into them before turning and moving around them. It doesn’t do this in a particularly rough manner but it isn’t particularly gentle either, and if you have fragile or precious furniture then it might be worth finding a model that’s lighter in its approach.

The other area in which this robot excels is at detecting whether it’s on carpet or hard floor. This ability, in combination with its self-controlled mopping function, means that the j9+ can be left to clean homes that have both hard floor and carpet without needing to have manual no-go areas assigned for the mop to avoid.

iRobot Roomba Combo j9+ review: How well does it clean?

I tested the vacuuming prowess of the iRobot Roomba Combo j9+ using the same suite of tests we run for putting every robot vacuum cleaner we review through its paces: spillages of rice, flour and pet hair, collected from both hard floor and carpet.

Rice on carpet proved to be the robot’s forté, where it picked up 99% of the spillage – this is well above average. There was a bit more scatter on the hard floor, throwing some grains out of reach, but the j9+ still managed to collect 89% of the spill.

Flour proved a tougher ask: the j9+’s rubber-coated rollers didn’t appear to be the best at gathering flour. Its lack of ability to combine strong suction with solid sweeping on hard floor, or stiff agitation on carpet being the root cause. These two features are found in many other of the best robot vacuums.

To make matters worse, the Roomba struggled to cover the entire area upon which we scattered the flour. This was either because it registered the spill as an obstacle to be avoided, or the flour had actually coated the inside of the collection bin and tricked the robot’s sensors into thinking it was full when only a small portion of the dust was collected.

On hard floor it collected 77% of the spillage, which is slightly below average; but not a terrible result. On carpet, it didn’t manage to pick up much before feeling the need to return home and empty itself, with only 30% of the spill collected. Needless to say, there was a lot left behind here. Its flour performance lets down the j9+ compared to its key rivals, as you can see from the chart below.

irobot roomba combo j9+ review spills cleaned

It performed better at picking up pet hair. On carpet it collected 99.6% of the dog hair trimmings that I scattered onto the floor during the test. It wasn’t quite so effective on hard flooring, with some of the hair getting swept aside or caught on parts of the robot as it passed by. Here it managed 66%, which is about average across all the robots I’ve tested. The best performing robot on pet hair that we’ve seen to date is the Ezviz RS2.

When it comes to mopping, I didn’t have the highest expectations of the j9+. The Roomba Combo j7+ has an identical system, with the mopping pad located on an arm that lifts over the back of the robot and moves the pad into position underneath as it’s needed. It then moistens the pad from its tank and drags it behind the robot as it moves.

Interestingly, though the robots appear physically identical, iRobot has made a number of changes to the mopping software. These significantly improve the process.

The main feature is called SmartScrub, which you can choose in the app. It appears to do two things: the first is to dampen the mop before it starts cleaning, by making a few passes in a small area to encourage the water to flow through before it starts to clean. The second is the movement of the pad backwards and forwards over each section it’s cleaning, going over any particular spot of floor three or four times as it inches its way forward.

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Frankly, this is a vast improvement over the previous system, which simply started wiping before the pad was wet and only went over each area once. The downside, which iRobot warns you about in the app, is that it uses more water and it may need to return to its base mid-mop cycle for a refill.

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iRobot Roomba Combo j9+ review: Should you buy it?

iRobot’s robot vacuum cleaners are hands-down the best at avoiding obstacles and the Roomba Combo j9+ is just as good as previous models we’ve tested. If you live in a house where you can’t – or won’t – guarantee a clear floor before the robot goes out, we would recommend a Roomba.

This is also the best hybrid mop and vacuum that Roomba has produced to date. It stumbled over our flour test, sure, but unless you live in a bakery, then you’re unlikely to regularly spill as much flour as we do to conduct our tests. In other tests the j9+ performed well, and matches its best rivals for its mopping capabilities – as long as you crank up the settings.

The only other robot we’ve tested that keeps both the water tanks topped up and the collection bin emptied is the Ecovacs Deebot X1 Omni. If you’re mopping mad, this is the better option, since it rinses the mopping pads as well as refilling the tank – something the Roomba doesn’t do. It can’t avoid dropped socks and charging cables, though.

If you don’t mind emptying your own collection bin, then you have a few more options to consider, including the Ezviz RS2 and the Eufy Clean X9 Pro. These combination vacuums and rotary mops keep both tanks topped up and pads rinsed, but neither offer self-emptying. We favour the Ezviz model, because it performed slightly better in our tests.

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