Roomba Plus 405 Combo
iRobot's mid-range vacuum and mop with spinning pads and a dock that empties, washes and dries. It maps quickly and resists hair tangles, but two tests found weak carpet cleaning and very wet mopping.
The short version
The Plus 405 Combo is part of iRobot's rebuilt Roomba range. It sits below the Plus 505 Combo, and it swaps the old camera-based navigation for a laser that maps rooms quickly. Two spinning mop pads lift when it reaches carpet, and the dock empties the bin, washes and dries the pads and refills the robot's water.
The trouble is the cleaning itself, which is what you're paying for. Both independent tests found it poor on carpet and at picking up pet hair from rugs, and one measured far more water left on the floor than usual. There's no camera for spotting cables and socks, the dock doesn't use hot water, and it's 10.6cm tall, so check the gap under your sofa.
Our take: Hard to recommend. If you want a Roomba for mostly hard floors and like the tidy dock, it will keep dust and pet hair down there. For carpets, pets or a cluttered home, look at the MOVA P10 Pro Ultra, which beat it in Vacuum Wars' direct comparison, or the Roborock Qrevo S5V, which testers agree mops well.
Where it sits in iRobot’s range
What reviewers found
Two independent tests, and both were disappointed. Vacuum Wars bought one and measured it over several weeks; BestReviews ran it in a two-level apartment with vinyl floors, rugs and carpet. Both found carpet cleaning and pet-hair pickup on carpet weak, and both had trouble with its mopping and the app. They disagree on everyday debris: Vacuum Wars found surface pickup more than adequate, while BestReviews saw bigger particles left on carpet.
Vacuum Wars, lab test, Several weeks · BestReviews, hands-on, Jan 2026
Weak on carpet and pet hair
Vacuum Wars measured 58% pickup in its deep-carpet test against an average of 75%, the worst it had recorded from a Roomba, and the lowest flattened pet-hair score it had seen. BestReviews found it left about half the small particles and faux fur on carpet in standard mode. If your home is mostly carpet, or you have a shedding pet, this is the main reason to look elsewhere.
Fine on hard floors and surface mess
Vacuum Wars found it swept up everything from fine to extra-large debris on hard floors and carpet surfaces without scattering it. BestReviews saw it clear 90% to 95% of faux fur from smooth hard floors, but on carpet it missed medium and large particles. The testers used different debris, which may explain the gap. Hard-floor homes will get the most from it.
Mopping leaves floors too wet
Vacuum Wars recorded a record score on dried-on stains, but only because it puts down so much water: it left about five times the average amount behind, and there's just one water setting. BestReviews found it spread a water spill around rather than soaking it up, and needed the slower deep-clean mode to shift old stains. The pads do lift over carpet, so rugs stay dry.
Quick mapping, no obstacle sensing
Its laser mapping impressed Vacuum Wars, which measured its best-ever Roomba coverage speed. BestReviews found the first map basic, with no automatic room split, so expect to edit it. Neither found a camera for small objects: BestReviews watched it tangle itself in cords twice in one run. Pick up cables before every clean.
Dock helps, app and noise don't
Vacuum Wars called the washing dock a big step up from iRobot's earlier ones, though it lacks hot-water washing and hot-air drying and was louder than average when emptying. BestReviews measured 80 to 85 decibels during emptying. Both found the new app a problem: buggy for Vacuum Wars, and confusingly laid out for BestReviews.
Prices
Where to buy the Roomba Plus 405 Combo in United Kingdom
| Retailer | Price | Delivery | Stock | Link |
|---|---|---|---|---|
| iRobotCheapest Official store | £599 | — | In stock | Go to iRobot |
We’re still looking for more United Kingdom retailers for this model. Prices shown are read from each seller’s own page.
Prices read from each seller’s own page on 23 September 2026. Some links are affiliate links and are marked where they appear. Commission never changes the order or the recommendation.
Before you buy
The questions people ask about this one
Will it avoid cables and pet mess?
No. Vacuum Wars notes it has no front camera or laser for spotting objects, and BestReviews saw it tangle itself in cords twice in one run and need freeing. Clear the floor first, and don't run it unsupervised around pet accidents.
Does it fit under low furniture?
The robot is 10.6cm tall with a laser turret on top, per the specifications. That's taller than many newer robots, so measure the gap under your sofa and bed before you buy.
Can it leave the mops in the dock for carpet?
No, but it lifts the spinning pads when it senses carpet, per the specifications. Vacuum Wars says that lets it vacuum and mop mixed floors in the same run. Neither test measured how high the pads lift, so be wary with deep rugs.
How big is the dock, and is it loud?
It's 45cm deep, 31.5cm wide and 47.2cm tall, per the specifications. BestReviews measured 80 to 85 decibels while it emptied the bin, and Vacuum Wars also found emptying louder than average. Put it somewhere you won't mind the noise.
How often do I have to empty or refill anything?
iRobot claims 75 days between dust-bag changes and four weeks of mopping and pad washing, per the specifications. BestReviews advises emptying the dirty-water tank often to stop smells, and the heavy water use Vacuum Wars measured won't help the clean tank last.
Compare with
P10 Pro Ultra
Vacuum Wars compared it directly and found it covers big floors efficiently, with a well-automated dock.
A lab found it leaves carpet edges dirty and struggles with embedded pet hair.
Qrevo S5V
Testers agree it mops well, and its dock takes care of most upkeep.
It also misses small objects, and testers split on pet hair.
Omni C20
A slimmer robot with dock automation that's reliably good at vacuuming hard floors.
Testers disagree about its mopping, and it can't spot small objects, so tidy up first.
Full specifications
Figures come from the manufacturer’s product page unless a source is named. A blank means nobody we trust has confirmed it.
Owner reviews
Own a Roomba Plus 405 Combo?
Tell people how it’s held up: cleaning, maintenance, faults and support. Owner reviews are shown separately from expert tests and never mixed into the score.
Sources
Everything cited on this page. Expert scores are shown as the reviewer gave them.
- Vacuum Wars: Roomba Plus 405 Combo review: great hopes, OK resultsLab test, Several weeks
- BestReviews: iRobot Roomba Plus 405 home testHands-on
- iRobot: Roomba Plus 405 Combo robot + AutoWash dockManufacturer