Are robot window cleaners any good? I tested one – here's what you need to know before you buy

Most people have heard of robot vacuums. Perhaps you're even aware of the existence of robot lawn mowers. But did you know that now you can even get your hands on a robot for cleaning your windows?

The first time I saw one of these window bots in action at a tech show, I was mesmerized. I watched, transfixed, as the bot made its way methodically across a pane of glass, gently buffing as it went. I knew I wanted to try one out in my own home, to see if it could move outside its comfort zone of an already-clean bit of demo glass and tackle my grimy windows instead.

For those whose homes have numerous glass windows and doors, a robot window cleaner is undoubtedly an appealing prospect. Manual window cleaning is messy, and generally requires you to hire a professional – in which case you're at the mercy of their schedule. But will a window bot do as good a job? And are there any downsides to outsourcing this task to a robot? Here's my take...

#1. Cleaning quality can vary

How well does a window bot actually clean, then? Unfortunately I can't give a definitive answer on this one. The window bot I tested did a pretty good job of clearing away surface dirt, but it left visible track marks wherever it pivoted on the glass (read my Hobot S7 Pro windowbot review for more). However, my colleague tested a different model and had nothing but good things to say about its cleaning prowess (more details in her Ecovacs Winbot W2 Pro Omni review).

What I can say for sure is that these cleaning bots aren't really for tackling the likes of bird poop or mud splashes – the cleaning is quite gentle, with not much water applied, so they're really only for surface dirt rather than anything more challenging.

#2. You will still need to supervise

While other robot helpers – robot vacuums, for instance – can be left alone to do their thing, window bots require human intervention. For starters, you'll need to be present to place the bot on each pane of glass and switch it on, and then remove it or shift it to the next pane once it's done. While using a window not will certainly save you some effort compared to manual cleaning, you'll need to be around while it's doing so.

There's also the question of how secure it is on the surface you're cleaning. One of the things that impressed me most when I first saw my window bot in action is how it adhered to the surface – it looked almost like magic. I was so confident in its stickiness that I stopped bothering to attach the safety cable when I left it to clean. So it came as quite surprise when, one morning, it simply dropped off the window with no warning.

I caught the rope and no damage was done, but there could have been – it was on the outside of a window on the third floor of a town house at the time. It only happened the once, and it seems like a freak occurrence, but I'd say it's still worth being diligent about attaching your safety rope to something, and keeping an eye on the window bot if it's in an area where a fall could potentially do some harm. Note that window bots will generally have a backup battery to keep them stuck for a short period, in the case of a power outage.

#3. They can get places a human can't

Aside from saved effort, the other big benefit of window bots is that they can reach places that human cleaners can't. For instance – the home in which I tested this bot has full-length windows that sit behind protective railings on one floor. For a person trying to clean behind those railings would prove a challenge (to put it mildly), but the windowbot snuck behind them with ease.

Oh, and they're not just for windows, either. Robot window cleaners can theoretically be used on any hard, flat surface. That means you can deploy them on your bathroom mirror or shower screen, saving you effort indoors as well as outside.