3 Months of Real Use — Across Two Units
The Roomba Plus 405 came into the studio for a three-month test and ended up taking longer than planned because my first unit was a dud. The dust-bag indicator light stayed red with a properly seated bag and wouldn't clear, so I returned it and got a second unit to complete the testing. The second unit functioned, but during pad drying the fan cycled on and off in a way I couldn't explain from the documentation. I can't say with certainty whether that's a second bad unit or normal behavior — and that uncertainty is itself a problem at this price tier. The final verdict came in at 4.6 out of 10, the lowest score in my current test pool, and a Skip It. There are a few things this robot does well — but more that it doesn't.
Two SKUs, Same Robot — G181 vs G185
Worth flagging upfront: two SKUs share the 405 name. The G181 is iRobot's Amazon Exclusive (the unit I tested), and the G185 is the standard retail SKU sold through Lowe's, Home Depot, and iRobot's own site. I looked for a meaningful spec difference between them and couldn't find one. Same dock, same mop, same suction marketing, same feature set. If you're shopping, the G181 and G185 are functionally the same robot — pick whichever is on a better sale.
What Works
LiDAR Navigation and Mapping
The spinning LiDAR under the dome maps quickly and accurately. Vacuums and mops in clean straight back-and-forth lines. Mapping was fast and the map matched the room well. This is real iRobot progress — the older Roombas without LiDAR took meaningfully longer to build a usable map of a home.
The New Roomba Home App
The redesigned Roomba Home app is a meaningful upgrade over the legacy iRobot app. The setup flow is cleaner, voice prompts are clearer, and the map editor — split rooms, merge rooms, keep-out zones, no-mop zones — actually works. The owner's guide is in-app and well written. For users coming off an older Roomba, this is the part of the experience that's going to feel like a real generational improvement.
Vacuum-Then-Mop Cleaning Mode
The cleaning mode menu includes Vacuum, Mop Only, Vacuum + Mop, and Vacuum Then Mop. Vacuum Then Mop is the right default for hardwood — it keeps the mop pads dry while vacuuming, then runs the mopping pass second. This is a feature most robots at this price tier ship with, but iRobot's implementation is clean and obvious in the app. Good call.
Brush Roller Serviceability
The 405 has a serviceability upgrade over the more recent Plus 505: single brush roller, but the end caps are designed to come off. Turn the end caps and the wrapped hair pulls out at the ends. A small cleaning tool with a hair cutter is included in the base. This is a small thing but a real one — and an example of where iRobot's legacy of pet-hair-focused engineering still shows up.
What Doesn't Work
Obstacle Avoidance Is Effectively Absent
This is the headline problem. The sensor on the front is for docking, not obstacle detection. If an item is taller than about 3 inches the LiDAR may register it; if it's heavy enough to trigger the bumper the robot will turn. Anything else — cables, small toys, low shoes — gets run over. In my test it ran over a low shoe. This is a significant gap at any price point, but especially at the 405's MSRP. The 1.0/10 score I gave on obstacle avoidance is the lowest single-category score in my entire test pool.
Price Doesn't Match the Feature Set
At MSRP there's no hot water mop wash, no hot air dry (room-temperature air only — drying defaults to 6 hours and the manual goes up to 12 hours), no internal water tank, no wetness-level control, no real obstacle avoidance, no edge-extending side brush, and a single-piece brush roller. Competing robots well below this price — the Roborock Qrevo S, the Mova P10 Pro Ultra, the Dreame L10s — deliver more for less.
Setup Friction
A mandatory firmware update at first setup took roughly 20-30 minutes and cannot be deferred. The app showed the update as complete in one place while still updating in another — I had to close and reopen the app to confirm completion. Some users are going to hit failed updates and need to reset Wi-Fi to recover from them. At this price, the setup experience should be smoother than that.
App Settings Are Sparse and Partially Redundant
Wetness level cannot be set in the app — only pad-wash frequency (50/100/150 sq ft). Suction and mode controls appear in two places in the UI, which caused me to misconfigure passes on a test cleaning. Room sequencing — the ability to clean rooms in a chosen order, a standard feature on Roborock, Dreame, and Mova apps — is not present here.
Hardware Reliability Concerns From This Sample
The first unit shipped with a dust-bag indicator that wouldn't clear and required a return. The second unit's drying fan cycled on and off during pad dry — behavior the documentation doesn't describe. Auto-empty teardown showed dust left in the bin (the auto-empty isn't fully emptying). Two units, three reliability concerns. That's a sample size of two, but it's the sample size I have.
Cold Water, Room-Temperature Dry
The AutoWash Dock does not heat the wash water and does not blow hot air during drying. The owner's guide setting goes up to 12 hours of drying for this reason. Competitors at this price tier are doing hot water wash at 167°F or higher and hot air dry in 2-3 hours. The Roomba 405 takes longer to dry because it has to dry without heat. That's a real day-to-day ownership cost.
No Physical Manual
A QR code on a small card in the box is the only documentation. The full manual is excellent — once you're set up in the app and can find it. For a non-trivial setup process with a 20-30 minute mandatory firmware update, having a paper quick-start in the box would be a useful piece of polish.
Roomba Plus 405 vs the Competition
Roomba Plus 405 vs Roborock Qrevo S
The Qrevo S sits below the 405's sale price and delivers a meaningfully more complete feature set: real obstacle avoidance, better mopping performance, a more capable app, and a split-brush hair design. For most buyers looking at the 405, the Qrevo S is the smarter spend.
Roomba Plus 405 vs Mova P10 Pro Ultra
Below the 405's sale price and a flagship-tier feature set: hot water mop wash, internal water tank, FlexiArm side reach, and meaningfully better hair handling. This is the same comparison that anchored the Plus 505 review — the Mova P10 Pro Ultra wins on specs and reliability, and the Roomba doesn't have an answer at this price.
Roomba Plus 405 vs Dreame L10s
Often the cheapest option in the cross-shop, sometimes well below the 405's price. Dreame's app is more capable than Roomba Home, the L10s has better obstacle handling, and the tri-cut brush design handles long hair where the 405 can't. For budget shoppers especially, the L10s is the better pick.
Roomba Plus 405 vs iRobot Roomba Plus 505 Combo
Inside the Roomba lineup, the more recent Plus 505 has Smart Scrub mopping and PrecisionVision AI obstacle avoidance — both real upgrades. The 405's only advantage over the 505 is the serviceable brush roller (the 505's ends don't pop off). If you're committed to a Roomba, the 505 is the better pick.