Best robot window cleaners: an expert guide to sparkling windows

If you struggle to clean your windows yourself, why not automate the job?

Robot window cleaners move around a pane of glass on their own, wiping away dirt and smudges as they go. Unlike the best window vacs, they'll do all the hard work – all you need to do is place them on the window.

According to Google Trends data, online interest in these handy gadgets has increased by around 850% in the past year in the UK, so their popularity is rising fast. 

We haven't tested robot window cleaners, so we don't know how successfully they'll clean your windows. But we have done some digging to find out what you need to know before you buy one, and we've found some online bestsellers to consider. 

How do robot window cleaners work?

Robot window cleaners stick to the glass using suction powered by an internal motor or a vacuum pump. They have microfibre pads and a water tank that sprays water or a cleaning solution onto the glass. Some use rotating round pads, while others have a square vibrating mop head.

They often include sensors to detect the edges and avoid obstacles, or they use smart AI mapping to measure the area. This helps them find the most efficient path to give your windows a thorough clean.

Most are corded and powered by the mains, but some are cordless and run on batteries for more flexibility.

Many also have an emergency battery system. This backup power ensures they stay securely attached to the window, even if their main power source is interrupted, for example if someone trips over the cable. 

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Popular robot window cleaner models

Which? hasn’t tested robot window cleaners, but we have pulled together retailer and search data to bring you a few popular options.

Ecovacs Winbot Mini Gen 2 Robotic Window Cleaner Robot

• Ultrasonic water spray
• Mains powered with emergency battery
• 21.5 x 21.5 x 5.5cm (HxWxD)

We like: Claimed to clean within 1mm of the edge of the pane

Watch out for: Needs to stay plugged in to power

This rectangular robot window cleaner automatically measures the window size and plans the ideal Z-shaped or N-shaped route to clean it effectively, returning to its starting position once it’s finished. 

Connect it to the Ecovacs Home app, and you’ll be able to toggle between five cleaning modes (fast, deep, thorough, edge and spot) depending on the type of dirt on your windows. 

Hobot S7 Pro Dual Mop Polish Window Cleaning Robot

• 26 x 26 x 8.9cm (HxWxD)
• Mains powered with emergency battery
• Dual ultrasonic water spray

We like: Includes heavy-duty safety rope to prevent falls

Watch out for: Needs to stay plugged in to power 

Hobot’s square window cleaning robot uses two microfibre pads and dual ultrasonic water sprays to clean dust, dirt and grime. It maps out the size and shape of the window to plan its route in a Z or N shape. 

There are three auto modes, and it will automatically return to its starting point when it's finished cleaning. There are also voice prompts to let you know its progress. 

Karcher RCW 2 Robot Window Cleaner

Buy it from Very (£180) 

• 29.2 x 16 x 7.1cm (HxWxD)
• Dual ultrasonic water sprays
• Includes a remote control 

We like: Includes a 4-metre safety rope 

Watch out for: Round pads might miss corners

Thanks to a set of optical and pressure sensors, Karcher’s RCW 2 robot window cleaner should detect the edges of glass so it doesn't fall or get stuck. There are two spray nozzles on either side to wet the glass before the robot passes over it, and two microfibre covers that rotate against the glass to wipe away dirt. 

It has four cleaning modes (quick, intensive, spot and finishing) as well as a manual mode, which you can control using the supplied remote. You can find out its progress and how much water is left in the tank using voice prompts and LED indicators. 

AlfaBot X7Pro Window Cleaner Robot

• Dual water spray system
• 60ml water tank
• 27.5 x 13 x 6.5cm (HxWxD)

We like: Sprays water in both directions of travel

Watch out for: Round pads might miss spots

The AlfaBot X7Pro uses edge-detection sensors and pre-programmed movement patterns to dictate how it moves around your windows. There aren’t any sensors to stop it from going too close to the edge of frameless glass, though. 

It has a couple of spray nozzles that mist the glass on both sides of the robot, and there are two circular mop covers that spin rapidly to clean smudges. 

Memows Window Cleaner Robot

• 29 x 14.4 x 9.3cm (HxWxD)
• 35ml water tank
• Ultrasonic water spray

We like: Comparatively cheap

Watch out for: Smaller water tank than others

This is one of the cheaper robot window cleaners that sits among Amazon’s bestsellers. It has two round discs covered in microfibre pads that rotate to scrub away smudges and dirt. 

There’s a misting system that keeps the surface moist while the pads work on the dirt, and it has pressure and optical sensors that detect the window's boundaries, preventing it from falling off. It’s mains-powered with an emergency battery, and it includes a 4-metre safety tether to prevent it from breaking if it falls off the glass. 

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What are the disadvantages of robot window cleaners?

While robot window cleaners handle the actual cleaning, you’ll still need to set them up manually, as they can’t move between panes on their own. Because of that, they're not suitable for grid or multi-pane windows because they can't navigate around them. 

Between uses, you'll need to remember to wash or replace the dirty cleaning pads to avoid spreading grime. They might also miss the very edges of the glass, as the pads don’t typically reach the edges of the device. 

If the suction fails, the device might fall and damage the glass unless secured with a safety tether inside the house.

What features should you look for in a robot window cleaner?

When choosing a robot window cleaner, consider the technology used, its power source and its cleaning methods, and pick one suited for your specific type of glass. 

• A square or rectangular body will be a better choice for cleaning right up to the edges of your windows. 
• Some need liquid to be sprayed manually onto the pads beforehand, while others have onboard water tanks and spray nozzles. 
• Decide on the power source. Most run on mains power, some have batteries, and others combine both, with a backup battery to prevent falls during power outages. 
• Ensure the power cable length works for your property layout.

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Should you buy a robot window cleaner or a window vacuum cleaner?

Window vacs are more often used for condensation, but they can also be used like a wet-suction squeegee to clean windows without leaving streaks or drips. 

Choosing between a robot window cleaner and a window vacuum depends on how much effort you're willing to put in and the types of windows you have at home.

If your windows or mirrors are easily accessible and you don't mind putting in a bit of effort, a window vacuum cleaner is cheaper and faster. 

However, for hard-to-reach spots on first or second-floor windows, a robot cleaner is the better option, although it will be more expensive.