Mixing water and carpets is a recipe for mold. In 2026, robot vacuums have finally learned how to keep your expensive Persian rugs bone dry while scrubbing your kitchen tiles.
The iRobot Roomba Combo j9+ uses a spectacular robotic arm to physically lift the wet mop away from the floor. The Dreame L20 Ultra takes a different approach: if the carpet is too thick, it drives back to the dock, detaches its mop pads entirely, and goes back to vacuum. Which strategy is the ultimate carpet savior?
The Carpet Strategy: Lift vs. Detach
Roomba j9+ (The Transformer):
It features the Retractable Mop Arm. When it sees a rug, the entire mop plate lifts up and swings over the top of the robot.
The Benefit: It is 100% safe for rugs of ANY thickness. The wet pad is literally on top of the robot, nowhere near the fibers.
Dreame L20 Ultra (The Detacher)
It has two rotary mops that can lift 10.5mm.
The Magic: If you have very thick shag carpets (deeper than 10mm), you can set the app to "Mop Detach" mode. The robot will go to the base station, magnetically drop the wet pads there, and return to vacuum your rugs without any mops attached. It is a slower process, but effective.
Cleaning Mechanics: Brushes vs. Rotors
Roomba (The Hair King):
Uses Dual Multi-Surface Rubber Brushes. Two green rollers spin in opposite directions.
Why it wins: This design is patented and remains the absolute best in the world for pulling pet hair out of carpets without getting tangled. It actively resists hair wrap.
Dreame (The Mopping King):
Uses Dual Rotary Mops that spin under pressure.
MopExtend™: One of the mop pads physically extends outwards (swings out) to clean right up to the baseboards. It eliminates the "dead zone" along walls that Roomba misses.
Navigation: Camera vs. LiDAR
- Roomba j9+: Uses Camera-based Navigation (vSLAM). It takes photos of landmarks. It is lower profile (fits under lower sofas) but struggles in pitch-black darkness. Its obstacle avoidance (identifying poop, cables, socks) is the industry benchmark.
- Dreame L20 Ultra: Uses LiDAR (Laser). It maps the house instantly and works perfectly in the dark. However, the laser turret adds height, so it might not fit under low furniture.
Comparison Table: 2026 Specs
| Feature | Roomba Combo j9+ | Dreame L20 Ultra |
|---|---|---|
| Carpet Protection | Retractable Arm (Top of bot) | 10mm Lift OR Detach at Dock |
| Mopping Type | Static Scrubbing Pad | Dual Rotary Mops (Spinning) |
| Edge Cleaning | Standard | MopExtend™ (Swing arm) |
| Price | ~$1,399 | ~$1,199 |
FAQ: Which handles pet hair better?
I have two Golden Retrievers.
Roomba j9+ wins. The dual rubber brushes are practically magic. Dreame's single bristle brush tends to get tangled with long hair and requires more maintenance (cutting the hair off the roller).
Does Dreame work in the dark?
Yes. The LiDAR navigation sees perfectly in total darkness. Roomba turns on a bright LED headlight to see, which might be annoying if you run it at 3 AM.
Buy Roomba Combo j9+ if: You have lots of carpets, pets that shed, and you want the absolute simplest, most reliable "set it and forget it" experience without complex maintenance.
Buy Dreame L20 Ultra if: You have mostly hard floors (tile/wood) and want superior mopping performance (rotary scrubbing + edge cleaning). The MopExtend feature is a game-changer for kitchen edges.