How To Use A Window Vac

Follow our step-by-step guide to see how easy using a window vac really is.
Written By: Richard Morgan | Updated:
How To Use A Window Vac
Richard Morgan/DIY Works

Rather than moving around buckets of water, squeegees and towels, a window vac is the best way to clean your windows. No matter how big or small the window, they are designed to leave a streak-free finish easily.

For this example of how to use a window vac, we use the best-rated window vac, the current Karcher machine. This particular machine is the “Anniversary” model, which features additional performance and a black design.

How To Use A Window Vac

1. Wipe Down With A Cloth

Before using a window vac, we advise that you wipe down your window with a cloth beforehand. Depending upon how dirty the windows are, you may be surprised by how much dirt is actually on the windows, as we show in the below photos.

Wipe Windows

Richard Morgan/DIY Works
Dirt From Wipe

Richard Morgan/DIY Works

2. Spray The Window With Cleaning Detergent

Using a window cleaning detergent of your choice, generously spray the window to be cleaned.

Soak The Window

Richard Morgan/DIY Works

3. Agitate The Cleaning Detergent

Although optional, for filthy windows, you may wish to agitate the cleaning detergent that’s been sprayed onto the window. This will help break down any stubborn dirt, which the window vac can then vacuum.

4. Use A Downwards Motion To Clean The Window

For the best results, it’s advised that you use a downward motion to clear the soapy water on the window. It’s important that you avoid letting the soap dry on the window because this will ruin the overall appearance.

5. Empty The Tank

Depending upon the number of windows you are cleaning, you may need to empty the tank. This water may be dirty, so pouring it straight down the sink is advised.

Our Top Tips

As you can see, using a window vac is very straightforward, but there are some top tips that we recommend to make it even easier. For example, rather than using a set of telescopic ladders to reach high windows, many brands offer extension poles that simply clip onto the device. This avoids all the hassle of moving the ladders to each high window.

For tackling small windows, we highly recommend taking advantage of any smaller attachments that the brand offers. For this exact reason, Karcher offers several small suction nozzles.

Finally, to improve the overall finish of the window, it’s important that you don’t forget to clean the other components of the window, such as the plastics/UPVC. Whether you use a dedicated UPVC cleaner or a diluted cleaner, cleaning the other parts of the window will vastly improve the overall finish of the window.

If you wish to see a window vac in action, below is a video that we posted on our YouTube channel:

Before & After Results

Before Window Vac Clean

Richard Morgan/DIY Works
After Window Vac Clean

Richard Morgan/DIY Works


Although a window vac can seem an unnecessary expense, it truly is a secret weapon when it comes to cleaning windows. Once you’ve used a window vac, you’ll never look back, and they can also be used for a range of other tasks, such as cleaning your shower screen to cleaning bathroom tiles. However, the main reason to purchase one is, of course, to clean windows, and hopefully, our guide on how to use a window vac shows you just how easy it really is.

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