We trialled 3 window cleaning robots – are they worth it?

• Hobot 2S for $608.70 from robotmylife.co.nz
• Rozie 1200 for $390 from windowrobots.co.nz
• Ecovacs Winbot W1 Pro for $889 from Noel Leeming, PB Tech, JB Hi-Fi

What is a window cleaning robot and how do they work?

Window cleaning robots may resemble a standard robot vacuum in shape, but they don’t actually vacuum your windows. Instead, the robot uses suction created by its motor to suck onto the window whilst it cleans via a mopping pad and water jets. It moves around using rubber track pads or by rotating the cleaning pads.

Edge sensors detect the window frames, and the robots will follow a pre-described route to clean the whole window before returning to its starting position.

Why would you want a robot window cleaner?

These robots aren’t cheap, so why would anyone choose one of these over a $5 squeegee, a bottle of window cleaner and some elbow grease?

First, it’s fun to watch a machine do a laborious task for you, right? And if you like a bit of tech, they are pretty cool to watch doing their cleaning shuffle on your windows.

Second, on a practical note, they could be indispensable for those of you with windows that are tricky to access – people in apartments or multi-storey homes who can’t access the outsides of their windows. With these window bots, you can lean out of an adjacent window (with safety in mind, of course!), stick the bot onto the dirty window and set it to clean.

Hobot 2S robotic window cleaner trial

First impressions of Hobot

The poorly named Hobot 2S is a square shaped unit with two spray jets on either side and a large cleaning pad underneath. It was smaller than I expected from images online and is reasonably well built, the plastic feels sturdy, surface finishes are good, and all the parts fit together neatly.

In the box:

• Three extra spare cleaning pads.
• A bottle of cleaning solution.
• A spare cable.
• Two spare ultrasonic jets.
• A power adaptor.
• A remote control.
• A clear, quick start guide.

Setup and use

Before using the Hobot 2S, you need to charge its internal battery. Oh cool, it’s battery operated you say? Well, unfortunately not. The unit always needs to be connected to the mains power; the internal battery is just a backup in case of a power cut, so the unit doesn’t fall off the window and squish your unsuspecting cat below. As an extra safety feature, there’s also a tether cord with a clip that should be attached to a piece of furniture or other immovable object, in case the robot slips off the window.

Once you’ve fully charged the battery, attached the tether and turned on the unit, a typical loud screechy robot voice will greet you: “Hello, I’m Hobot. Please tie the safety rope before use … ” The suction fan will also start up, so prepare your ears for the racket!

Then you place the unit onto the window, and it sucks itself on rather like the face hugger in the first Alien movie. Rest assured it isn’t coming off.

To start cleaning, use the remote included or the Hobot smartphone app via Bluetooth. Both have the same functionality, so it doesn’t matter which you choose. Left, right and up are the three options for starting a clean- this tells the bot what direction to start cleaning in. It doesn’t matter which way you go, the robot will eventually clean the whole surface anyway.

There is a toggle to clean twice, and one to turn on and off the automatic cleaning spray. A manual spray button allows for an extra squirt in any dirtier areas after you have driven Hobot there using the direction buttons.

Hobot recommends you do the initial clean on dry windows to remove dust before doing a wet clean. You can then change the pad and turn on the auto spray.

Hobot will clean in a line, zig-zagging its way to the next section until it's finished the window. Annoyingly I found the Hobot didn’t return to its starting position, which can make it harder to retrieve from the outside of windows. In this case, you can use the direction buttons on the remote or app to move the bot into a more accessible position.

How well does Hobot clean?

If your windows are particularly dirty to start with, don’t expect the Hobot to give you a crystal-clear finish. I found that it tended to smear any fly spots or larger spots of dirt around the window.

Hobot suggest that you use the 2S to maintain your windows after a proper manual clean. The bot uses two ultrasonic sprayers to “nebulize” the proprietary window detergent, meaning it converts liquid into a fine mist. Inside this works fine, but outdoors even a light breeze will blow this fine spray away from the window rendering it useless.

I also found that if you are too generous with the manual spray feature or have already cleaned several windows and the pad is getting quite wet, then the bot will start to slip on the glass and won’t be able to climb up to the top of the window. This is probably a major flaw with the whole concept of a robotic window cleaner – you need a liquid to clean the glass, but this liquid can affect the robot’s grip on the window.

Hobot verdict

As this was my first experience using a window cleaning robot, I really didn’t know what to expect. I certainly enjoyed watching the Hobot do its routine, but I wasn’t particularly impressed with the results, especially outside.

Rozie 1200 window cleaning robot trial

First impressions of Rozie

A better named robot, the Rozie also looks completely different to the other two machines in this trial. The website states “voted best Window Robot 2023”, although it’s not clear who did the voting. A figure-of-eight shape with two circular cleaning pads and a single cleaning solution reservoir and spray jet on the left side. It looks a little like a giant shoe shine unit for a clown.

In the box:

• Four pairs of microfibre cleaning pads.
• One spare pair of pad mounting rings.
• A filling bottle.
• Power adapter and cable.
• Remote control.
• A poorly written user guide.

It’s fairly well built but does have a certain AliExpress vibe about it, especially with regards to the packaging and instructions translation.

Setup and use

Like the Hobot, Rozie has an internal UPS battery (Uninterruptible Power Supply) that you need to charge before using. While charging, I attempted to use the smartphone app “Wobot” to connect, but it was all in Chinese with no English language option, so impossible for me to use. The NZ distributor has since advised me that an English version of the app is coming with the next iteration of Rozie.

Luckily, an app isn't essential, as robot window cleaners are sufficiently automated. I used the remote control instead. Assembling Rozie involves stretching the cleaning pads over the plastic rings before clipping onto the main body and be warned – this can be a tad tricky.

Rozie doesn’t come with any cleaning solution; the distributor suggests using water with a few drops of white vinegar. Mix this in the supplied bottle before adding it to the reservoir.

The bot also needs to be tethered before you start a clean, then it’s time to turn the unit on and let it suction itself to the window. The distributor recommends doing a dry clean first, much like the Hobot 2S. An extra set of cleaning rings means you can pre-mount cleaning pads onto the spares ready to do the wet clean once the dry has finished – they are easy enough to clip on and off.

To get Rozie started, choose which direction it will head in first, up, left or right. Each circular pad rotates independently and allows the whole unit to move and wipe at the same time. Rozie only really cleans horizontally, even if you send it to the top of the window. Once it senses the window frame, it will start cleaning from left to right or vice-versa. When doing a wet clean, Rozie squirts the cleaning solution between the pads and then wipes over straight after.

How well does Rozie clean?

I found quite a lot of smudge marks on my windows, even after using the suggested dry clean following by a wet clean.

So, I decided to run the wet clean first, changed the pads to clean dry ones and ran the dry clean last as a buffing step. This order worked much better and cleaned most of the smudges left from the first clean.

However, Rozie’s spray struggled to reach the top edges of my windows, meaning they stayed dirty. I was also left with circular marks where I removed Rozie from my window that needed to be buffed off by hand.

Like the Hobot 2S, I had issues with Rozie’s grip if the pads got too wet – it couldn’t shuffle or climb the glass properly.

Rozie has a better spray system for the outside, though. Unlike Hobot’s nebulizing nozzle that converts liquid into a fine mist, Rozie’s cleaning fluid stays liquid, so wind doesn’t stop the spray getting onto the glass.

Rozie verdict

I was surprised to find that Rozie was a more capable cleaner than I thought it would be from my initial impressions. I would choose it over the Hobot as it’s cheaper and I achieved a better result on the outsides of my windows.

Ecovacs Winbot W1 Pro Robotic Window Cleaner trial

First impressions of Winbot

I don’t know about you, but I always like to buy a product with the word “Pro” in the name. It must be better, right? The Winbot comes in a very pro-looking attaché style case, which looks like it could be concealing a James Bond-style Q secret weapon.

In the box:

• A spare cleaning pad.
• A small bottle of the proprietary Ecovacs window cleaning fluid.
• All the associated cables and power supply.
• A large and clear quick-start guide.

There is no separate remote with the Winbot, control over the bot is solely via the “Ecovacs Home” smartphone app, and you have to scan a QR code to add the robot to the app.

The Winbot W1 Pro is a square cleaner like the Hobot, with two spray jets on top and bottom. It’s a well-built unit with a faux leather brown strap handle.

Setup and use

Like the other window cleaning robots tested, charge Winbot’s UPS battery first, then tether the cord to an item of furniture near the window. Then you can follow the setup guide on the app or on the quick start card.

To start cleaning, wet the cleaning pad first, wring it out, and then attach it to the underside. Next, you fill the reservoir with cleaning fluid by popping off a small rubber cap on the top of the Winbot.

Once switched on, Winbot will automatically suction itself to the window and start cleaning when it senses you have pressed it onto the glass. You can choose to manually turn on the suction before attaching to the window if you prefer, but the auto start feature is pretty handy.

Winbot is just as chatty and loud as all the other Ecovacs robots. Luckily there is a volume slider in the app settings, which I highly recommend turning down.

The app has three main cleaning options:

1. Fast will clean your window once.
2. Deep will clean your window twice and pay extra attention to corners and edges.
3. Spot will do an extra clean over a specific area that you drive the unit to.

Winbot follows a standard route – it will head to the top of the window and then clean horizontally down to the bottom. It turns 90 degrees to clean so that the sprays are horizontal too. Once cleaning has finished, it returns to the starting point. It is quite noisy on the glass, especially when it turns.

How well does Winbot clean?

Winbot does a reasonable cleaning job if your windows aren’t too dirty. It’s better at getting into the corners and edges than the Rozie, due to its square shape, but it will still leave some dirt marks along the edges.

However, slipping was a major issue during testing – I found that the lower track would often slip and push the unit higher up the window. The Winbot only stayed on the top half of the window and never cleaned the lower half, leaving me with a super clean top half and much dirtier lower half.

Despite this issue, at least I could see Winbot can clean. I decided to test with a dry pad instead of the recommended wet one, which solved the problem. It did still slip a little, but it managed to clean the whole window.

I also found that the tether cord and power cable were a little short compared to the other bots (only 3m compared to 4m on the Rozie and Hobot), so cleaning the outside of some of our large windows had both cable and tether at their max extension which isn’t ideal.

Winbot verdict

Ecovacs Winbot W1 pro has some nice user experience touches, such as the auto-start when the unit is pressed onto the window, and Ecovacs proprietary cleaning solution does a good job of cleaning and drying clear (beware though, replacement bottles are $40 a litre). However, it’s a premium product in design and price that still suffers from similar issues to the other trialled bots, and it’s really not worth paying the extra.

Window cleaning fluid trial

The liquid you use to clean your windows can have a huge effect on the final result. Using tap water can leave marks after drying due to minerals and impurities (especially if you live in a hard water area).

The latest innovation in professional window cleaning is called reverse osmosis (RO), whereby the water used is finely filtered to remove all minerals and impurities. The water is then known as deionized or demineralized water (DI water). This water is then “hungry” for dirt when used for cleaning, and it also has the advantage of drying without any residue when used for rinsing. Most professional exterior window cleaners in the UK now use RO systems.

How does reverse osmosis relate to our robotic units?

Ecovacs and Hobot supply their window bots with a deionized water-based solution that dries clear. But bottles of these solutions are expensive - $40 a litre for the Ecovacs one, and $55 for 5x220ml bottles from Hobot.

I wanted to see if deionized water from the supermarket would give me the same window cleaning results for a fraction of the price. I used a bottle of pure water available at the supermarket for around $1.75 a litre. This water has undergone a reverse osmosis process, but how would it compare to the Ecovacs’ solution?

The trial involved smearing greasy fingerprints on two glass panes of my French doors (using olive oil spread), cleaning one pane with the Winbot using the Ecovacs’ solution, and the other pane with the Winbot and pure water.

The results were comparable, but the Ecovacs solution dried quicker, giving a slightly better clean than the pure water, probably due to a small amount of detergent in the solution itself. It was difficult to see the difference, though, so if you do decide to get a window bot, it’s worth trying out RO water from the supermarket. You could add a few drops of white vinegar to aid cleaning, as the Rozie crowd suggest.

Incidentally, when I filled the Winbot with the pure supermarket water, the unit alerted me twice that the reservoir was empty – the water was so pure the level sensor couldn’t detect it!

Final verdict: Should you buy a robot window cleaner?

Rozie and Ecovacs Winbot W1 Pro were the winners in our trial, as the Hobot’s spray system means it’s pretty ineffective outside. None of the units trialled does that great a job though.

So it comes down to the price – Rozie wins here but still isn’t cheap at close to $400. Winbot costs double and produces similar results, albeit with a much more polished user experience.

When considering a robot cleaner, the question is can you be bothered with the set-up of one of these units and the time they take to clean when a bottle of cleaning spray and squeegee might take less time to clean all your windows than the bot would take to do one?

I think it’s inevitable that I will eventually purchase one as I have several windows that are very difficult to access from the outside, and these units solve this problem well. But if access isn’t an issue for you, I’d suggest waiting until the tech improves for better cleaning performance and easier setup.