Updated 30 March 2022
Do you find it difficult to wash windows? We’ve tested a number of window vacuums from Kärcher. In order for an electric window vacuum to be named Best in Test, it must be easy to use, have a good battery life and, most importantly, it must get your windows really clean.
Our tests are independently conducted and reflect the test editor's honest and objective opinions. Selection of products and test results are in no way influenced by manufacturers, retailers or other internal or external parties.
We carry out our tests ourselves and test all products as they are intended to be used in reality. A window vacuum is a machine a bit like a vacuum cleaner for your floor, which sucks up the water after you use the supplied spray bottle and cleaning cloth to wet and wash the window.
In our test of window vacuums, we washed different types of windows, in ordinary houses and apartments. All electric window vacuums were used on several occasions over a period of about a month. In the test we focused on the following characteristics:
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Small and compact window cleaner – ideal if you want to clean in tight spaces
Price range: Medium Accessories supplied: spray bottle with microfibre cloths, charger (micro USB and plug connector), extra nozzle for small panes Width of nozzles: 266 mm and 133 mm Container volume: 100 ml Specified runtime: 30 mins
The Bosch window cleaner is considerably smaller than most of its rivals on the market. The short body allows you to easily clean all the way down to the windowsill and in other confined spaces that would otherwise be difficult to access.
GlassVAC from Bosch is considerably shorter than its rivals. Instead of the standard rectangular dirty water tank, the Bosch is a little shorter and compact, which means that you can easily access all corners and drag the window scraper in one go all the way down to the edge of each pane. This, combined with the superb quality of the blade – whose rubber more closely resembles a classic window squeegee than many other window vacuums – means that it leaves the fewest streaks in the test. If the rubber blade had been attached to a slightly longer, flexible section that allowed you to angle the machine even more, it would have been perfect. It also comes with a smaller rubber blade nozzle that measures just over 13 cm and is ideal for narrower panes or mullioned windows. This also works flawlessly and leaves no streaks behind.
The low height of the machine also makes it feel significantly easier to handle than a more rectangular vacuum of the same weight. The handle is comfortable to hold and on the whole feels very easy to manoeuvre, even in tighter spaces, such as when we clean windows behind a kitchen sofa, the back of which tends to ‘catch’ other cleaners. Since it leaves no streaks, you can also clean sideways in areas that are more difficult to access. The suction power is excellent and the microfibre cloth on the spray bottle, which alternates larger and smaller fibres diagonally, also works very well
The GlassVAC is charged with a micro USB, which is brilliant if you lose the charger – that makes it easy to replace and you can use the household’s standard micro USB. An indicator around the on/off button lights up red while the vacuum is charging and changes to green when it is fully charged. It also comes with a small wrist strap to which you can attach the machine. Using the wrist strap ensures greater safety if you should happen to drop the window cleaner or need to let go of it temporarily, for example to climb down a ladder.
The most negative thing about GlassVAC is its dirty water tank, which is built into the machine and impossible to remove completely. You empty it through a small hole covered with a rubber lid. It works, but some of the dirty water always runs over the machine and needs to be rinsed off. If you want to clean the container more thoroughly, you remove the nozzle and let the water run through the entire machine, shake and empty it out through the small hole again.
The battery life of 30 minutes is perfectly acceptable and similar to most machines on the market in this price segment.
Flexible window vacuum with long operating time, suitable for those with lots of windows to clean
Price class: Premium Accessories included: Spray bottle with microfibre cloths and one dose of detergent Nozzle width: 28 cm Container volume: 150 ml Specified operating time: 100 min
At first it’s not entirely clear why the WV 6 Plus has fewer accessories than cheaper window vacuums from Kärcher. With this machine you only get one nozzle, 28 cm wide. On the other hand, the included spray bottle is a little bit more advanced. But after using the vacuum for a while, it becomes clear why the WV 6 Plus costs as much as it does.
Getting started with the Kärcher WV 6 Plus is very easy. You plug it in to start charging and about an hour later you can clean your windows. One dose of detergent is included with the purchase and, according to Kärcher, this is enough to fill the spray bottle once. But we didn’t notice any difference in the result if you dilute this with twice as much water. Then you just clean the window and then turn on the window vacuum, which automatically sucks up the water as you sweep it over the glass.
The spray bottle attachment for the microfibre cloth can be adjusted between two different widths using the extension included. In the narrower position, you fold the excess cloth around the back. It would be practical to be able to adjust the width when you wash the windows. But since you can’t do that with the window vacuum itself – which is often the bit that’s hardest to get into corners and edges – there’s not much point to the idea.
However, one thing that works very well is the digital display on the WV 6 Plus. Clear numbers indicate the remaining battery life in minutes as soon as you switch on the window vacuum. This means you get a decent idea of how many windows you’ll have time for. Since the operating time is a generous 100 minutes, for most homes one charge is enough for several rounds of window washing. You should even have time to clean the shower cubicle or glazed patio.
The Kärcher WV 6 Plus is very easy to use. The large container for dirty water is easy to remove, empty and rinse clean. But the best detail, and the one that most facilitates washing your windows, is the fact that the nozzle has a softer, rubberised edge. This means the window vacuum requires much less manual force when you press it into the lower edges of the windows. It’s also easier to get into angles and corners. Since you don’t have to press as hard, you can also hold the WV 6 Plus in your hand for a longer period of time.
In terms of the end result, our assessment is that the WV 6 Plus is comparable to other window vacuums from Kärcher. If you don’t wipe the nozzle off after each pass, there’s a risk of streaky windows – especially at the top of the glass where you first start to suck up water with the scraper. But if you don’t mind standing with a cloth in your other hand, the WV 6 Plus produces windows that are nice and clean. If you find cleaning windows a drag, the Kärcher WV 6 Plus will make the process faster, easier and more fun.
Fast-charging window vacuum for people with windows of different sizes
Price class: Intermediate Accessories included: Spray bottle with microfibre cloth, one dose of detergent and a small nozzle Nozzle width: 28 cm and 17 cm Container volume: 100 ml Specified operating time: 35 min
Kärcher's WV 2 Plus N comes with two nozzles. It’s easy to switch between nozzles on the machine, but it takes a fair bit of finger strength to press the button in properly. Usually you have to use both hands. The small spray bottle is handy in size but needs to be refilled a few times to clean all the windows in a normal-sized house.
With the microfibre cloth attached to the spray bottle, the window can be wetted and washed in one movement. The microfibre cloth is attached with Velcro so it’s easy to remove for machine washing. On the first use, some fibres come loose and produce streaks when the window dries. After the first wash of the microfibre cloth, that problem goes away.
It’s really fast to charge the Kärcher WV 2 Plus N battery, and after just over an hour the window vacuum is ready to use. The specified operating time is 35 minutes. That doesn’t sounds a lot, but considering the short periods you use the machine, it does go quite a long way. A normal-sized window dries quickly with the wider nozzle. However, the narrow nozzle is really handy when you need to dry smaller glass sections such as windows in an exterior door, or windows with glazing bars.
There is some difference in the suction ability of the two nozzles. The smaller one sometimes leaves a strip of liquid at the edge, even if you apply extra pressure. That’s something that doesn’t happen with the larger nozzle. The rubberised edge of both nozzles is quite hard, which makes it difficult to get into the lower edge of a window.
After cleaning, the water collector must be emptied. There’s an opening on the outside, but this is in the middle and so it’s almost impossible to get the last drops out. It’s more efficient to remove the collector completely and empty the water through the larger opening and then rinse it clean.
The WV 2 Plus N requires a fair amount of force to perform. But considering that the model is in the lower half of the price range for Kärcher’s window vacuums, it has all the features you could wish for. Of course, the result won’t be as good as when a professional cleans your windows. But it’s good enough and it’s also pretty quick.
A window vacuum with extra battery for lots of windows
Price class: Premium Accessories included: Spray bottle with microfibre cloth, one dose of detergent and a small nozzle Nozzle width: 28 cm Container volume: 100 ml Specified operating time: 35 min
It’s kind of natural to wonder what distinguishes the different window vacuums from Kärcher. The Kärcher WV 5 Plus N differs from the other machines in this test in that it has a replaceable battery – something the other two vacuums don’t have. The battery is, of course, rechargeable, but even rechargeable batteries can sometimes reach the end of the road. The battery life is quite good, but if you have many windows to clean, this machine allows you to have a spare charged battery on hand – so you don’t have to wait for the machine to recharge before you can finish cleaning the windows.
You can quickly charge the Kärcher WV5 Plus N so that just half an hour after unpacking the vacuum, you can start to clean your windows with it. Together with the machine, you get a small bag of detergent that you dilute with water in the spray bottle. If you’re going to clean lots of windows, make sure you get extra detergent when you buy the vacuum. Because if you live in a house with lots of windows, this small bag probably won’t be enough.
A slightly streaky result
You can adjust the width of the scraper on the Kärcher WV5 Plus N. This should make it easier to access the corners. There’s also a smaller nozzle, which makes it easier to clean things like vent lights. Adjusting the width of the scraper is a bit fiddly, but once you get the hang of it, it becomes easier.
But regardless of whether the width is adjusted or not, it’s impossible to avoid the windows coming out somewhat streaky. Despite the fact that we tested different angles at different temperatures and several times over, and that the pressure was varied, the scraper still created narrow streaks. It also spatters around drops of the detergent, which also leaves marks on the glass.
All of these problems can be solved if you equip yourself with a microfibre cloth and quickly follow the vacuum around with that. But for close to £100, we’d have liked the Kärcher WV5 Plus N to live up to its promises on the packaging of “streak free” washing, three times faster than normal window cleaning. There are clearly streaks, and by the time you’ve got rid of them with a microfibre cloth, you’re back to the same sort of length of time as if you’d washed them with a more traditional method.
A window vacuum works in a similar way to an ordinary vacuum cleaner. It scrapes the glass and “vacuums” up the water all at once, so no dirty water runs down the window below the rubber blade and onto the window sill or ledge. The dirty water that is sucked up is collected in a small container that you empty once you’ve finished cleaning. A window vacuum often comes with a spray bottle with a fitted microfibre cloth that you use to wet the window and rub off stubborn dirt.
A good window vacuum sucks up dirty water without leaving streaks on the pane and has a battery life that lasts long enough to clean all the windows in a normal-sized home. It should also not be too heavy for you to hold. It’s an added bonus if it’s easy to empty out the dirty water and to keep the vacuum clean.