Kärcher K4 Full Control Home Pressure Washer review

Welcome to T3's Kärcher K4 Full Control Home Pressure Washer review. Each year T3 tests out the very best pressure washers on the market to ensure that anyone who is looking for a system can buy quality and get a great user experience.

This review covers the Kärcher K4 pressure washer, which sits in the middle of the German makers range, above the K2 and K3 systems but below the K5 and K7 machines. The specific package tested here is the Full Control Home Pressure Washer, which includes some extra accessories over the base K4 model.

This Kärcher K4 review is broken down into a few different sections: we start with a video showing exactly what the K4 is capable of in terms of patio cleaning, before showing off some before and after gallery images of the overall results.

We then move onto the K4 itself, taking a look at its design, performance and accessories, before finishing off with an overall verdict. We've also pulled in the very best Kärcher K4 deals, too, meaning that anyone who is interested can immediately see the best prices on offer.

• Kärcher KHB5 review – the cordless alternative

Kärcher K4 Full Control Home Pressure Washer video

As you can see from the above video, when tasked with cleaning a filthy, neglected, mould-covered patio, the Kärcher K4 absolutely nailed it. The system, equipped with its hard power lance absolutely peeled the muck off — it was like a marker being erased from a whiteboard, one use and it is gone. And the really crackers thing about it was that it was literally zero physical effort, I just pointed the lance at what I wanted to remove and seconds later it was gone. Superb.

Kärcher K4 Full Control Home Pressure Washer: before and after image gallery

Image 1 of 6

These before and after pictures really show the awesome job the Kärcher K4 did cleaning the patio. In the before shots the flagstones look like they belong in a dystopian cemetery, covered in detritus, mould, animal excrement and years of filth. In contrast, after an hour or two cleaning them with the Kärcher K4, they look bright and fantastically fresh, with the whole patio looking like new. The K4 did such a good job that the original two-tone flagstone colours became visible once more, adding an extra level of aesthetic beauty to the whole garden.

Kärcher K4 Full Control Home Pressure Washer: design and build quality

Putting the system together out of the box took 15 minutes. The system comes with the main body and key piping already assembled, and then just requires the owner to affix peripheral things like its handle, wheels, LED trigger gun, lance holders and cable management pouch.

Once fully assembled, design-wise the Kärcher K4 is a very aesthetically pleasing pressure washer. Narrow and tall, with a bright yellow and black colour scheme, the system stands comfortably on its own and, thanks to some included wheels, is easy to roll around on the ground, too.

Typical usage of the system involved getting the system from storage, hooking up its power chord (I always did this with an external power extender to give me more flexibility in length), connecting the system to a water source (I did this via external tap, which was fitted with a quick connect/release attachment that I had been using with my Hozelock hose nozzle) and then priming the system.

Priming the system involves ensuring the right lance attachment is fitted (they snap in and off quickly) and then turning the motor on a waiting roughly two minutes for it to build up pressure. Once this is achieved, the LED trigger gun can be used.

Security features are also a strong point for Kärcher K4. The LED trigger gun, for example, has a small unnoticeable trigger locking mechanism built into the handle, which means small children can't cause unwanted damage when your back is turned.

Kärcher K4 Full Control Home Pressure Washer: performance and accessories

As you can see from the above video and image galleries, the Kärcher K4 performed superbly in terms of patio cleaning. And after switching lances for a softer spray, I also found it incredibly useful in terms of cleaning my Mercedes-Benz CLS500.

Without the Kärcher K4 I had no way to clean the patio, while washing the car was a process of using my garden hose along with buckets of soapy water and a dump truck load of elbow grease. With the Kärcher K4, though, much of that labour was removed, with the soft water flow lance blasting off any fixed on dirt and muck, before a once round with the car wash and sponge and further blast leaving the vehicle looking like new.

For me the Kärcher K4 shone most when car cleaning in terms of getting alloys looking all sparkly. With an open face my vehicle's alloys tend to lock dirt inside in awkward to reach places (such as between the alloy's spokes), however with the Kärcher K4 I could easily blast these interiors and recesses clean in minutes.

Other uses of the system included cleaning an exterior door in preparation of a sanding and painting job, cleaning exterior windows and window frames and sills, as well as giving both my family's push bikes and my motorbike a thorough cleaning. For the cycles in particular the Kärcher K4 was an excellent time saver when returning from rides off-road where large chunks of mud had got wedged in the tyres and frame.

This versatility of use is where plumping for the "Home Pressure Washer" variant of the K4 comes in useful, as this model comes with a T350 patio cleaner and a one litre bottle of 3-in-1 stone and facade cleaner. The K4 also comes equipped with Kärcher's  excellent LED display trigger gun, which helps guide you to correct pressure setting for the thing you are cleaning.

Kärcher K4 Full Control Home Pressure Washer: verdict

The results, as can be seen vividly in this review, speak for themselves — the Kärcher K4 Full Control Home Pressure Washer is simply fantastic cleaning system that hits a brilliant sweet spot of powerful motor and max water pressure, excellent cleaning performance, wide-ranging and useful accessories and an affordable price point.

The Kärcher K7 Premium Full Control Plus Home is technically a more powerful system, but for the vast majority of users, the K4 is the unit I would recommend buying as it achieves 95 per cent plus of the functionality for common household pressure washing tasks for going on half the price.

From resurrecting a long-neglected patio, to cleaning your home's exterior and windows, and onto washing your vehicles and more, the Kärcher K4 delivers exactly what you need from a pressure washer and I wholeheartedly recommend it.

• Best barbecue 2020: large BBQs, grills and smokers