My window-cleaning robot leaves streaks after every pass
Home Nura guide — category: Window Cleaning Robots
Diagnosis
A window-cleaning robot that leaves streaks nearly always has a dirty or worn pad, or the wrong amount of cleaning liquid. Streaks appear when dirt is just moved around and the water dries too fast, especially on warm or very hard-water-stained glass.
Possible causes
- Dirty or worn pad — it no longer holds onto grime and redeposits it as fine lines on every pass.
- Too much water or cleaner — the excess runs down, dries in drops and leaves rings or runs along the bottom of the glass.
- Glass in direct sun — the liquid dries before it is wiped and leaves white streaks of limescale or soap.
- Very dirty glass or a greasy film — one pass is not enough and the dirt is spread out without being absorbed.
Recommended steps
- 1Remove the pad, hand-wash it in warm soapy water without fabric softener, rinse it well and let it dry before putting it back on.
- 2Wipe the frame and ledges with a damp cloth first, so the robot does not smear dust and grit across the glass.
- 3Clean windows in the shade or on an overcast day, and spray a moderate amount of the manufacturer's recommended cleaner.
- 4For very dirty or greasy glass, do a first cycle with little cleaner, then a second with a clean pad.
- 5Rinse the drive track and suction seal with clear water, and check that the pad is held taut by its fasteners.
Repair or replace?
If streaks persist with a new pad and a suitable cleaner, check the suction and the condition of the seal. A robot that keeps losing power or has a warped seal is rarely worth repairing and is better replaced.
If you decide to replace it
Window Cleaning Robots: the shortlist from our buying guide
- View on Amazon →
Best overall
Ecovacs Winbot W2 Omni
Portable battery station, self-winding safety cable, three-nozzle spraying and edge detection for frameless glass.
Photo: © ECOVACS
- View on Amazon →
Best value
Cecotec Conga WinDroid 1090 Double Spray Connected
Double spray, 8 modes, app and remote control, safety cord and a roughly 30-minute battery in case of a power outage.
Photo: © Cecotec
- View on Amazon →
Best for frameless glass
Hobot 2S
Compact and light, two ultrasonic nozzles, edge sensor, 4.5 m rope and a backup battery lasting up to 20 minutes.
As an Amazon Associate I earn from qualifying purchases. Amazon affiliate links: commission at no extra cost to you.
Other common problems in this category
These issues affect the same type of appliance — each one comes with a diagnosis and the recommended steps.
- Window Cleaning RobotsMy window-cleaning robot keeps losing grip and nearly falls
- Window Cleaning RobotsMy window-cleaning robot beeps non-stop and reports low suction
- Window Cleaning RobotsMy window-cleaning robot leaves a streak in the centre of the glass every pass
- Window Cleaning RobotsThe suction pad on my window-cleaning robot is losing grip and the unit slides
Frequently asked questions
Usually, yes, if the failure shows up during the warranty period and isn't caused by misuse. A product in the Window Cleaning Robots category bought new from an authorized retailer normally comes with a manufacturer's warranty: check its length in the manual or on the brand's website. Consumer protection rules also vary by province and territory, so keep your proof of purchase.
If you're still within the store's return window, a return or exchange is usually the fastest fix. After that, the manufacturer's warranty takes over: its customer support can arrange a repair or a replacement. Even outside the warranty, the manufacturer can often repair the device for a fee. Either way, keep your proof of purchase.
Our public methodology lowers the Nura Score /10 of any model in the Window Cleaning Robots category whose recurring failures are documented in owner reviews. A model that breaks down too often never tops our rankings, whatever the brand.
Generally, yes. Routine maintenance, such as cleaning, replacing a gasket or recalibrating, is part of normal use and doesn't usually affect your warranty. Irreversible changes to the hardware are what can cause problems. For a product in the Window Cleaning Robots category, stick to the steps described in the manufacturer's manual and read the warranty terms before going any further.
When a product fails in its first few months of normal use, the cause is usually a manufacturing defect. Contact the seller or the manufacturer with your proof of purchase and a description of the symptom: for a model in the Window Cleaning Robots category that is still under warranty, this is the typical case for a free repair or replacement. Warranty terms vary by brand, so read yours.