Mel has been using the Kärcher Window Vac for several years, on a daily basis throughout the winter months, to remove water from single-glazed windows. It is also frequently used on the shower and to vacuum up spillages from the kitchen worktop. About the author I sprayed the cleaning solution on the harder-to-reach areas of the shower screen first, then turned on the window vac. I moved in a vertical direction and could see the buildup (almost) vanish. This was a great result. Before I could start cleaning I needed to set up the window vac. Since I hadn't used such an appliance before, I was relying on the instructions included in the box. These were terribly poor, comprising a set of linear drawings – as opposed to step-by-step written instructions – to provide some clue as to what to do with the appliance. I interpreted the double-sided A3 sheet of instructions as best I could, and did get the Karcher Window Vac working –but the process could have been easier.

The water tank, which holds 150ml of dirty water, is also easily removed for emptying. Since dirty water takes some time to accumulate, you won't have the hassle of frequent emptying. However, the WV2 does have some minor disadvantages. We found that the spray bottle/cleaning head tool was a little bit fiddly to put together and on the first attempt we did not screw the trigger head on correctly and ended up with a wet floor. Most of the issues seem to be surrounding the water bottle. It has a tiny capacity which may be annoying for extended cleaning periods or if you live in a larger house. Additionally, there are no volume lines to measure out the mixture of cleaning fluid to water. We think that volume lines would be a useful feature as the instructions provided state that you should add 230ml water to the 20ml of cleaning fluid. All said and done we managed perfectly fine in our small window cleaning test and we think we could live with the small problems that we have discovered. Test no.1: Window cleaningIt comes with two interchangeable squeegee heads, which can be detached from the suction nozzle for cleaning after use. These heads measure in at 18cm and 28cm. Both feature the new lip technology to allow for upper-edge cleaning to the ground without interruption, to achieve a streak-free finish.

Among its many included accessories are a smaller 170mm suction head for hard-to-reach areas and a microfibre attachment to spread detergent on your windows. There’s a built-in LED battery indicator and you can buy additional batteries so that you’ve always got a fully charged one ready to go.

The Karcher WV2 Plus Review: In summary

Log in now or join Which? to see our full results and find out if any Karcher window vacs are good enough to earn our Best Buy recommendation. After a good charge of around two hours, we used the Karcher for cleaning windows (a set of small French doors). It took us around two minutes to clean the windows which involved first spraying them with the cleaning tool then going over a couple of times with the vac.

So, what can the window vac be used for? Well obviously, the main use is for cleaning windows but in our experience, it can also be used for cleaning shower doors and removing condensation from surfaces. The window vac is extremely versatile and we found it particularly useful for cleaning up liquid spills but you may find it handy for other applications. In fact, it will perform great on all smooth surfaces. What’s in the box? I had high hopes for the Karcher Window Vac WV 6's cleaning performance. I live in an old house with high ceilings and, therefore, have numerous tall windows to clean. None of that would matter if the Karcher didn’t clean windows brilliantly – and that’s where it really excels. Suction is strong and efficient right across the nozzle, so you can clean and dry into the silicone seal around your windows. The finish is about as streak-free as a window vac can achieve, although you may want to give your glass a final buff with a dry kitchen towel. We select top-selling window vacs from leading UK retailers and put them through a string of tough tests to find out which are the best. Suction power is excellent and you get oodles of extras in the box, including a smaller head and microfibre attachment. However, what pushes the Bosch behind the Karcher and Vileda in our list is its failure, reported by some users, to clean quite as well to the very edges of your windows.The battery is integrated into the window vac, so you'll need to plug in the entire appliance for charging. The LED display proved useful as an indicator of how much charge, minute-by-minute, the Karcher Window Vac had accumulated, and also consumed when in use. LED charge indicator: Useful for revealing how much longer the battery will last before it needs a recharge. Having added the cleaning concentrate to the spray bottle with 150ml of water, my first cleaning job with the Karcher Window Vac WV 6 Premium was the three- window bay in my front room.

I have to say I was impressed by the results. Surprisingly, I didn't have to repeatably go over the area with the spray bottle, and the squeegee blade wiped away all of the diluted concentrated cleaning liquid to reveal a shiny surface – with no water marks to be seen. Mel said: “In the mornings in the winter, because we're not double glazed, the water is running down our windows and it's obviously going to damage the paintwork. With this, I can vacuum all of it up. It’s brilliant and it doesn't take very long.” Cleaning extras: Many window vacs come with cleaning bottles, microfibre pads and even their own branded cleaning spray. While useful, these extras are unlikely to perform any better than the stuff you already have in your cleaning cupboard.The spray tool is very easy to use and the vac did a good job of cleaning up the dirty water first time. We only had to re-do a few small areas. We only used washing up liquid in the cleaning bottle but overall the windows looked clean and streak-free when we’d finished. We must mention that there was some stubborn bird poo on the window and we had to redo this area. We feel that if your windows are extremely dirty then some preparation might be needed beforehand to ensure the vac is as efficient as possible.