Roomba Plus 405 vs 505 (2026): A $200 Gap That's Really an Obstacle-Avoidance Camera

Quick Answer: The Roomba Plus 405 ($799.99 list) and Roomba Plus 505 ($999.99 list, now commonly $499-$599) share the same AutoWash dock concept but tested at opposite ends of iRobot’s own 2026 lineup. Vacuum Wars measured the Plus 405 at 1.85/5, ranked 70th of 200+ robots, with the lowest pet-hair score the site has recorded. Tom’s Guide calls the Plus 505 “the best Roomba overall,” backed by an 82/100 aggregate score (Criticaster) — it adds a PrecisionVision AI obstacle-avoidance camera, a real published 7,000 Pa suction spec, and heated mop-pad drying that the 405 lacks entirely. The $200 list-price gap buys a genuinely different robot, not a minor upgrade.

Same product line, same AutoWash dock branding, same year — but these two numbers tell a split story. iRobot’s Plus 405 and Plus 505 Combos both launched in 2026 as part of the company’s push to finally match Roborock and Dreame on LiDAR navigation. One of them landed at the bottom of an independent testing rig. The other is topping “best Roomba” lists. Here’s exactly what separates them.

The one feature that explains the price gap

The headline difference isn’t suction or mopping — it’s a camera. The Plus 505 pairs its ClearView Pro LiDAR with PrecisionVision AI, a forward-facing camera built to recognize and steer around cords, socks, shoes, and pet waste by name. The Plus 405 navigates with LiDAR alone and has no dedicated obstacle-avoidance sensor array at all, per Vacuum Wars. For households with pets or kids’ toys on the floor, that’s not a nice-to-have spec-sheet bullet — it’s the difference between a robot that drives around a problem and one that drives through it.

Head to head

Cleaning performance: not a close call

This is the part where the two models genuinely diverge. Vacuum Wars tests every robot on the same rig — same debris, same carpet depths, same pet-hair mats — and under that bar the Plus 405 scored 1.85 out of 5, landing 70th out of 200+ robots tested. Its 50% flattened pet-hair pickup is, in the reviewer’s own words, “the lowest score we’ve seen yet,” and its 58% deep-carpet pickup trailed a 75% field average.

The Plus 505 wasn’t run through the identical Vacuum Wars suite, but the signal from independent reviewers points the opposite direction. Tom’s Guide’s hands-on reviewer says they’re “never going back to my regular stick” vacuum, specifically citing strong corner-reaching, floor-scrubbing, and pet hair handling — the exact category the Plus 405 measured worst in. Aggregator Criticaster backs that up with an 82/100 composite score, well above where iRobot’s other 2026 launches have landed.

Obstacle avoidance: the 505’s standout

PrecisionVision AI is the feature iRobot built specifically to solve the most common robot-vacuum complaint — eating a charging cable, tangling in a sock, or tracking through pet waste. The Plus 405 has no equivalent; it relies on LiDAR mapping alone, which is excellent for building an accurate floor plan but isn’t designed to recognize and avoid small objects in real time. If your floor has cords, toys, or pets on it regularly, this single difference should decide the purchase on its own.

Both ship in large, heavy Combo-dock boxes — get either one to your door in two days with an active Prime account: try Amazon Prime free for 30 days.

Mopping: both have a real idea, one executes it better

Give the Plus 405 credit here — its 145 stain-removal score (93 average) beats even some category leaders. But Vacuum Wars also measured 5.20 grams of residual water left on the floor after mopping, roughly 5x a 1.01g field average, which is why the same review called the mop “unsuitable for actual floor maintenance despite the good stain score.” The Plus 505 addresses the drying half of that equation directly: its AutoWash dock heat-dries mop pads instead of air-drying them, and its pads extend sideways for PerfectEdge coverage along baseboards that the 405’s pads don’t reach. Neither model lets a rushed read of “mop score” alone tell the full story — drying matters as much as scrubbing.

Price: the real gap is smaller than list price suggests

At MSRP the 505 costs $200 more ($999.99 vs. $799.99). In practice that gap compresses and sometimes reverses: New Atlas reported the Plus 505 settling closer to $499-$599 by mid-2026, while iRobot has run promotions discounting the Plus 405 up to $400 off its own list price. Both numbers move independently of each other and change with sale cycles — check current pricing on each before assuming the $200 list-price delta still applies.

The bottom line

The Plus 405 and Plus 505 look like a simple step-up pair from the model numbers alone, but independent testing shows a much bigger split: the 405 measured at the bottom of Vacuum Wars’ field, while the 505 is landing on “best Roomba” lists. The PrecisionVision AI camera, a real published suction spec, and heated mop-pad drying are the concrete reasons why. Unless the Plus 405’s current discounted price undercuts the 505 by a wide margin, the extra spend buys a robot that independent reviewers actually recommend rather than one flagged as a letdown. For the full picture on either model, see our dedicated Roomba Plus 405 review and Roomba Plus 505 review, or compare iRobot against the competition in our Roomba vs Roborock breakdown and best robot vacuum for pet hair rankings.

Check today’s Roomba Plus 505 price on Amazon →