Review: Karcher’s latest cordless window-cleaning tools

Can Karcher’s new window-cleaning gadgets leave your panes clean, dry and streak-free?

Karcher KV 4 Cordless Vibrating Wiper and WV 6 Plus Window Vac.

During Covid-19 lockdown, staring out at a beautiful day, I realised my home’s windows were atrociously dirty. Window cleaning sucks and it’s the chore I skip the most. Fortunately, I’d taken the Karcher’s KV 4 Cordless Vibrating Wiper and WV 6 Plus Window Vac home to try.

Karcher KV 4 vibrating window washer

The window washer is about the size and shape of a belt sander. It has a detachable cleaning cloth and onboard water tank. At the touch of a button it gently vibrates, while another button dispenses water through the cloth. The vibration is meant to create friction so it’s easier to clean your windows.

Karcher KV 4.

I tackled my biggest window first and, to my surprise, it did a decent job. Only using water, it easily removed all surface dirt. But what about tougher jobs, such as stuck-on bird poop? Not so much. To give it a helping hand, I sprayed on some glass cleaner (see our test results) on the window first, then gave it another go with the wiper ‒ bye-bye bird poop.

I was initially afraid to use it on my windows, fearing the vibration could break them. But it’s quite gentle and, unless you have thin, 100+year-old windows, you should have no worries.

The manufacturer claims the built-in battery lasts 35 minutes before needing recharging. I found I could wash the inside of all windows in my four-bedroom home on one charge. It took just over two hours to recharge the battery from empty. Cleaning up was a breeze – just empty the leftover water from the tank down the sink, remove the cloth (which is attached by Velcro) and throw it in the washing machine.

Karcher KV 4 cleaning a bench.
The KV 4 isn't just for windows – it can also be used to clean other household surfaces such as benches, tables, ceramic hobs and showers.

The KV 4 performs well, but it has a few drawbacks. At 500g, it’s not light, meaning it can be awkward reaching high windows. I also found it too bulky to fit behind the handle on my ranchslider, so I needed to use a cloth for a thorough clean.

But you’re not limited to cleaning windows and glass with the KV 4. You can use it on other household surfaces, such as benches, tables, ceramic hobs and showers. My favourite was using it on my glass splashback, where it did a good job of removing cooking residue.

Overall, it’s an interesting gadget. Though it’s no quicker at cleaning windows than a cloth and bucket, it is easier – the onboard tank meant I didn’t have to bend down to a bucket. The novelty factor also helped me tolerate cleaning windows, a previously hated chore.

Karcher KV 4 specs

Karcher KV 4 with cleaning cloth and 20ml sample of Karcher glass cleaner concentrate.

Price: $ 131

  • Weight with empty tank: 500g
  • Dimensions (Lx W x H mm): 260x94x100
  • Dirty water tank capacity: 180ml
  • Run time: 35 minutes
  • Charge time: 160 minutes
  • Includes: Cleaning cloth and 20ml sample of Karcher glass cleaner concentrate.

Karcher WV 6 Plus window vac

With the colder weather setting in, condensation forming on windows is a common problem for many homes. Removing this moisture can prevent mould growing. This is where the WV 6 Plus Window Vac comes in handy.

This cordless squeegee effortlessly sucks up water from your windows into a 150ml container attached to the handle. It can be used at any angle and its head is thin enough to fit behind latches. The container did start to leak when the water was above the max line, so it's important to empty the container when it becomes full. It’s also easier to dispose of this water compared to a cloth or traditional squeegee – simply tip it down the sink.

Karcher WV 6 Plus window vac.

Preventing streaks isn’t easy with the window vac. You need to use light pressure and angle the head just right. You could use a good streak-free window cleaning spray (see our test results) to help. I accepted the occasional streak was inevitable and, as a friend pointed out, birds are less likely to fly into streaky windows.

Removing the cleaning cloth from the Karcher WV 6.
The cleaning cloth can be removed from the WV 6 and thrown into your washing machine.

For window-washing, the WV 6 Plus window vac comes with a separate water spray bottle with removable washing cloth. I found the low-tech spray bottle did just as good a job of washing as the KV 4 vibrating window washer. The cloth, attached by Velcro, can be thrown into the washing machine when you’re done.

The Window Vac may not leave windows streak-free, but it’s great at drying them. It’s easy to use and clean-up is simple. I’m looking forward to quickly sucking up morning condensation with it this winter.

Karcher WV 6 Plus specs

Price: $ 190

Karcher WV 6 Plus with spray bottle, cleaning cloth and 20ml sample of Karcher glass cleaner concentrate.
  • Weight with empty tank: 800g
  • Dimensions (Lx W x H mm): 126x280x310
  • Dirty water tank capacity: 150ml
  • Run time: 100 minutes
  • Charge time: 170 minutes
  • Includes: Spray bottle with cleaning cloth and 20ml sample of Karcher glass cleaner concentrate.

WV 2 vs WV 6: what’s new?

In 2016, we trialled the Karcher WV 2 Plus window vac back, so how does the latest version compare? The WV 6 has a larger water storage tank (150ml) and a beefed-up battery with a runtime of 100 minutes, which should be ample for most homes. In comparison, the WV 2 only held 100ml of water and had 25 minutes of runtime. However, a bigger battery means a longer charge time –the WV 6 takes 170 minutes to charge. It’s slightly heavier, likely due to the battery increase, but still easy to handle and manoeuvre.

A cheaper alternative, consider a Scoopy

Scoopy with cloth and box.

In our 2016 review, we also compared the window vac to the $20 Scoopy, a manual squeegee with a water container for the handle. I have one of these at home and it does a good job, but the WV 6 Plus window vac is quicker and easier to use and can reach the bottom of my ranchslider, which my Scoopy can’t.

First Looks are trials of new and interesting products from the perspective of our product experts. Our lab-based tests offer truly objective product comparisons.

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Andrew Thompson
06 Jun 2020
Karcher window cleaner concerns

The Karcher is a great window cleaner and speeds up the cleaning and drying process. We have had two Karchers. The first one stopped charging after two years, we replaced it and the same thing happened again after about 18 months. We would still buy a battery operated window cleaner but I am not confident that Karcher is a reliable option.

Linda O.
06 Jun 2020
Karcher recharging

My Karcher stopped recharging. Put it away in the garage. Lightbulb moment "maybe it's the charger?". It was. Working perfectly now. Charger bought from Mitre10.