This list is for homes with big or hard to reach windows. A robot qualifies if it comes with a base station, which lets it clean on battery power without a nearby wall outlet. Check how heavy the station is to carry between windows, since one here weighs 10 kg, and whether it washes the pad or leaves that to you. How we score.
Last gen Ecovacs station model, now much cheaper than the W2S line
SUCTION 5,500 Pa max, 2,800 Pa while moving (brand claim)SPRAY Auto spray, 60 ml tankBACKUP BATTERY 4,500 mAh battery, 110 min runtime; stays attached over 30 min at low power (brand claim)FRAMELESS Supported, framed and framelessSCORE 8.2
Cheaper W2S with the same 8,000 Pa claim and TruEdge scrubber
SUCTION 8,000 Pa (brand claim)SPRAY Three nozzle spray; Ecovacs lists an 80 ml tankBACKUP BATTERY 3,000 mAh battery; stays attached over 30 min at low power (brand claim)FRAMELESS Supported, framed and frameless flat windowsSCORE 7.4
Newer cordless Winbot with a bigger tank, minus pad washing
Why it ranks here
Basic Tutorials scored it 92/100, the best single test score here, with navigation that needed no intervention. It ranks below the Hobot because it costs about $200 more. It beats the W3 Omni by costing about $200 less with a similar battery station, though you rinse the pad by hand.
SUCTION Up to 10,000 PaSPRAY 3 nozzle, 120 mlBACKUP BATTERY 110 min cordlessFRAMELESS Yes, optical sensorSCORE 7.0
Flagship window robot whose station washes the pad for you
Why it ranks here
CyberShack rated it 4.5/5 and found results better than hand cleaning, but it is the most expensive robot here, which puts it last among scored models. Its station washes the pad for you. Gizmodo saw streaks and missed areas on tapered frames, and reviewers noted a faint pad outline.
SUCTION 3,300 Pa movingSPRAY Auto, 80 mlBACKUP BATTERY 130 min cordlessFRAMELESS Reported by GizmodoSCORE 6.3
Ecovacs window robot with a portable battery station for big glass
SUCTION 8,000 Pa max, 3,000 Pa while moving (brand claim)SPRAY Three nozzle spray, 80 ml tankBACKUP BATTERY 4,500 mAh battery, 110 min runtime; stays attached 30 min or more at low power (brand claim)FRAMELESS Supported, framed and frameless flat windowsSCORE not yet