Goal-based
Robotic window cleaners: which design fits which window?
All three units require manual placement per pane, but they diverge sharply on cleaning approach, surface requirements, and how much the owner manages between runs.
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The investigation
5 questions this comparison examines
Which surfaces does each unit actually work on?
Surface compatibility is the first constraint that narrows the field. Framed or textured glass creates adhesion and path-tracking failures that override any cleaning-method advantage.
Ecovacs Winbot W2 OmniHOBOT 388 UltrasonicMamibot iGLASSBOT W120-TMamibot documentation explicitly restricts use to smooth glass; textured or frosted surfaces are listed as incompatible due to suction failure risk.
Ecovacs and HOBOT documentation describe edge-detection sensors as the primary boundary method on flat glass; neither documents textured-glass operation.
How does each unit apply cleaning fluid to the glass?
The three units use two distinct cleaning methods. That difference affects pre-run preparation, fluid consumption, and whether the owner handles the fluid step or the robot does.
Ecovacs Winbot W2 OmniHOBOT 388 UltrasonicMamibot iGLASSBOT W120-THOBOT 388 manufacturer documentation (2026) confirms ultrasonic vibration atomizes cleaning fluid from the onboard reservoir onto the glass surface, distinguishing it from pad-scrub designs.
Ecovacs W2 Omni documentation describes pad moisting via the Omni dock station; Mamibot W120-T documentation requires owner pre-application of fluid before each run.
What path intelligence does each unit use on the glass?
Edge detection and path planning determine whether the unit covers the full pane systematically or leaves strips requiring a second pass. The three units sit at different points on this dimension.
Ecovacs Winbot W2 OmniHOBOT 388 UltrasonicMamibot iGLASSBOT W120-TEcovacs documentation describes optical edge detection with boundary mapping as the navigation method; HOBOT documentation describes systematic path algorithms with edge sensors.
Mamibot W120-T documentation lists RF remote control as the primary manual-mode interface; no app or Wi-Fi connectivity is documented for this model.
How much does pad and fluid maintenance fall to the owner?
Between-run maintenance varies from near-zero to entirely manual depending on whether a dock station automates the process. That difference compounds across a household with many windows.
Ecovacs Winbot W2 OmniHOBOT 388 UltrasonicMamibot iGLASSBOT W120-TEcovacs Omni dock documentation confirms the station automates cleaning-pad maintenance without manual intervention, a capability not present on the HOBOT 388 or Mamibot W120-T.
HOBOT 388 and Mamibot W120-T documentation describe manual pad rinsing and pre-run fluid preparation respectively; neither product ships with a maintenance dock.
What placement and safety burden applies to each unit?
All three require manual mounting per pane and safety tether management; none travel between windows autonomously. Price spread across the three maps to those additional capabilities, not to placement automation.
Ecovacs Winbot W2 OmniHOBOT 388 UltrasonicMamibot iGLASSBOT W120-TAll three products document manual placement and safety cable management by the owner; no unit in this set automates inter-window transit or self-mounts.
Ecovacs documentation notes ground-floor residential use as the documented operating context; MSRP figures sourced from manufacturer documentation (2026) for all three products.
In closing
What the evidence shows
Patterns that emerged across the questions above.
Cleaning method splits before price does
The HOBOT 388 is the only unit using ultrasonic atomization; the other two rely on scrub pads. That architectural split exists independently of the $149 to $999 price spread.
Dock automation is not evenly distributed
Only the W2 Omni ships with a station that automates pad maintenance between runs. The other two return full maintenance responsibility to the owner after each session.
The placement ceiling applies equally across all three
Manual mounting per pane and owner-managed safety tethers are shared constraints across Level II and Level III units here. Price and dock automation do not change that floor.
Common questions