How to choose a window cleaning robot

What matters when buying a window cleaning robot: how it stays on the glass, what happens if power fails, whether it handles frameless glass, how it sprays and wipes, how well it reaches corners, and when a squeegee is still the better tool.

Researched by the robotsforthat team · updated Oct 15, 2026 · How we research

Suction and the safety rope

Every window robot holds on with a fan that creates suction under the body. Brands quote big peak numbers, but the moving figure is lower: Ecovacs lists the W3 Omni at 3,300 Pa while moving even though its marketing mentions 10,000 Pa. Compare like with like.

The safety rope is the real backstop. TechRadar's reviewer skipped it once and the robot fell off a third floor window; when attached, the cable caught it. Ropes are rated differently, from 100 kg on the Ecovacs W3 Omni cord to 1,600 N on the Winbot mini 2 rope, so check the rating and always anchor it indoors.

Battery backup and power

Corded robots such as the Mova N1 and Winbot mini 2 clean on mains power and carry a small battery only to stay attached if power drops, about 30 minutes on both. Hobot lists 20 minutes on the 2S.

Station models from Ecovacs put a battery in the station instead, rated at up to 130 minutes on the W3 Omni and 110 minutes on the W2S Pro Omni, so you do not need an outlet near the window.

Framed vs frameless glass

On a framed window the robot bumps the frame to find the edge. On frameless glass such as shower screens, balustrades and mirrors it needs an edge sensor, or it can drive off the side.

Results vary. TechRadar found the Ecovacs W2 Pro Omni worked on frameless glass, while EFTM saw the Mova N1 slip on a frameless shower screen. Gizmodo found the W3 Omni could not detect tapered frames. If most of your glass is frameless, pick a model that lists frameless edge detection and read reviews that tested it.

Spray and pads

Robots spray a fine mist ahead of a microfiber pad. Tank sizes range from 50 ml on the Winbot mini 2 to 120 ml on the Mova N1 and W2S Pro Omni. Reviewers of the Mova N1 and the Ecovacs W2S Omni reported some drips reaching the sill.

Dirty pads cause streaks. Basic Tutorials had to rinse the W2S Pro Omni pad about every two windows on heavy dirt, and Gizmodo saw streaks when the W3 Omni pad was too dry. Only the W3 Omni station washes the pad for you; Gizmodo put a replacement pad set at $32.

Corners and speed

Square robots with corner scrubbers, such as Ecovacs TruEdge models, get closer to frames. Galaxus found a round pad Hutt model imprecise at corners and slow, at just over 17 minutes for about 4 m² of glass.

Real timings vary by mode. EFTM measured the Mova N1 at about 5 minutes in Quick mode and 11 minutes in Thorough mode on one 800 x 1300 mm window, while Gizmodo timed the W3 Omni at a little over 2 minutes in Fast mode on a 4 by 3.5 ft window.

What to skip

Skip a window robot if you mostly have small panes: TechRadar NL and Gizmodo both said a squeegee can be faster there. They clean glass only, so frames and sills still need a cloth.

Do not expect them to run unattended or to remove caked on dirt. TechRadar notes you must place the robot on each pane and stay nearby, and that bird droppings and mud are hard for them. Never run one on outside glass without the rope attached.