Kärcher K4 Premium Power Control Pressure Washer Review

The Kärcher K4 Premium Power Control Car and Home pressure washer is a mid-range washer aimed at domestic use yet powerful enough to tackle an extensive list of hardcore cleaning tasks.

Alongside the two main nozzles, this model is supplied with a Home Kit, which is a patio cleaning brush and stone detergent, plus Car Kit with foam nozzle, wash brush and car shampoo. In short, it can dirt-bust a wide range of surfaces with ease and will help keep your garden design and motor looking shiny and new. 

I finished a major extension project just last summer, including landscaping, but after a particularly miserable and muddy winter here on the edge of Dartmoor, it was all looking a little grimy and worse for wear. The Kärcher K4 Premium Control pressure washer couldn’t have landed at a better time. 

The flat roof of our extension was particularly disgusting. A situation not helped by a combination of the green gunk (sap, algae, who knows?) from the surrounding fir trees and our roofer’s failure to achieve the correct draining gradients towards the downpipe. Sigh. 

In March my dad spent a whole day pressure washing the patios and paths, bless him, but I still had plenty to keep me busy around the patio area while testing the Kärcher K4 Premium Control. I also tested its car cleaning prowess in the hope the Kärcher K4 Premium Control would save me a few pennies at the car wash. 

Find out how the Kärcher K4 Premium Control pressure washer performed on my flat roof, car and many other surfaces (warning: the cleaning gets a bit addictive), then check out more options in our buying guide to the best pressure washers. 

Getting Started 

The Kärcher K4 Premium Control pressure washer arrives in a reasonably compact box that tucked under our stairs until I was ready to unpack. It was heavy, 19.1kg to be precise, but I could just about carry it inside without help. 

Sadly, there were several components to assemble, including the wheels, stand, storage attachments and so forth, before I could start washing. I won’t moan too much as it’s worth remembering that a ready-to-go product would have required a far bigger box, and thus a far bigger carbon footprint to get it to my house in the middle of Devon.

The instructions were a mix of illustrations and written information, the former too small to really compute and the latter ridiculously brief. Frustrated, I downloaded the Kärcher Home & Garden App in the hope of finding an assembly video, failed, and then headed to good old YouTube where someone called Big Ted did the honours! 

In fairness, it isn’t very hard to put the Kärcher K4 Premium Control pressure washer together and it’s a helpful process to learn how the nozzles and pipes connect, but I enlisted a cordless screwdriver to speed things up. 

Once I’d plugged in the power to our outdoor socket and connected to the hose (the fittings are the universal size for garden hoses) we were ready to rock. It’s worth noting that the Kärcher K4 Premium Control pressure washer can also be used with a water butt or tank, so you don’t need an outside tap. 

What is the Kärcher K4 Premium Power Control Like to Use?

Before draying the Kärcher K4 Premium Control pressure washer onto the roof, I had a little play around with the two main spray nozzles. They are easy to switch up, using a push and slide locking motion. The first one, called the Power Control spray lance, is the serious dirt buster that delivers the hardest, most effective pressure. 

Then there is the Vario Power Control spray lance, which offers more variety — twist the nozzle to move the pressure between Hard, Medium, Soft and Mix (for soap dispensing). 

Finally, there is a car brush and patio head attachment, and all of these various spray nozzles/brushes are connected to the main Power Control gun, which is the part you hold in your hand. I tried the two main nozzles, just to check the machine worked (it did, phew) and how the pressure felt to help decide what I might need for my first job. 

Wheeling the Kärcher K4 Premium Control pressure washer along to where you need it is very easy thanks to the extending handle (think wheelie bag) and huge wheels. It also helps that the high-pressure hose is wound around a hose reel at the back and there are storage slots for the various nozzles, so it all stays tucked neatly together during transport. 

Cleaning a Flat Roof with the Kärcher K4 Premium Power Control

I am quite certain the Kärcher K4 Premium Control pressure washer isn’t designed to be lifted out of a second-floor window but that’s what we did to get it onto the flat roof of our extension. I’d already climbed out the window and my husband passed it out. Easier than dragging it up a ladder, we decided. 

As mentioned, this roof was looking grim — not the most welcoming sight when you pull back the bedroom window curtains in the morning. A clean was long overdue. After connecting the hose (passed up from the patio below) and plugging it in from the bedroom, I selected the Power Control spray lance as I quickly realised only the strongest pressure was going to cut through the grime. 

Our existing pressure washer, inherited when my parents upgraded, has different spray head options so you can go for a wider fan-like spray that covers a bigger area. I couldn’t see this option on the Power Control pressure washer but the round spray it gave off did the job and was about three times more powerful than our existing pressure washer (probably why my parents upgraded). 

With the pressure at full bore it took less than an hour to power off the green algae-like stains from the roof and force all the dirt down the gully and away. I was incredibly impressed by how the Kärcher K4 Premium Control pressure washer removed every stain and inch of dirt with ease. No need to go over any areas twice. 

The results speak for themselves below…

BEFORE CLEANING:

AFTER CLEANING:

Cleaning Patios and Paving

Buoyed by my success on the roof, I gathered up the pressure washer, disconnected the hose/plug and passed it back through the window, before carrying it downstairs and out to the patio. It was heavy and a little unwieldy, but I could manage without any assistance, which was handy since the husband had gone to watch rugby.

Once there, I reconnected the hose and socket before switching from the Power Control spray to the patio head, which is officially called the T5 Surface Cleaner. This is a large round yellow drum with a rotating spray arm inside that spins at high speed, delivering water as it goes. It is designed to clean stubborn stains and soiling from durable surfaces such as tiles, concrete and stone. You can also switch the rotor arm height adjustment to ‘soft’, for use on more sensitive surfaces.

Next, I loaded the bottle of 3-in-1 Stone & Facade cleaner into the docking mount on the pressure washer. But not before removing the grey cap from the detergent bottle, which required serious force and would be better as a screw-twist action than pull off plug. The mount is the same shape as the bottle, so hard to miss.

Turning the ignition dial to On, I started up the pressure washer up and the patio head lifted off the ground like a hovercraft, whoosh! It took a little practice to get the right push and glide action required to move the patio head along the stone slabs I wanted to clean but it didn’t require any physical exertion at all. 

I could see large circles where the rotating arms were working through the dirt, hugely satisfying, and the large circumference of the drum meant the job took no time at all. 

The results were brilliant. Admittedly the actual sandstone patio slabs weren’t too bad after my dad’s March blast, but the slate slabs on the top of the walls that he had missed (sorry dad) were transformed. 

BEFORE:

AFTER:

Cleaning a Car using the Kärcher K4 Premium Power Control

Not having to take the car to the car wash (or laboriously toil with a wimpy garden hose and sponge) holds a lot of appeal when you live in the middle of nowhere. Determined to get the best possible results, I opened up the Kärcher Home & Garden App on my iPhone where I’d spotted a step-by-step walk-through earlier.

The App gave me 14 steps to follow, some of which – like brushing leaves from the windscreen and putting bug spray on the lights – I merrily ignored. I did find the order in which to use different nozzles useful though. 

Starting with the Vario Power spray in Mix mode, and the car shampoo in the detergent docking mount, I sprayed the car with soap and left it for five minutes to do its work. Next, I turned the Vario Power to Medium and washed off the soap and dirt underneath. Then I took off the Vario spray arm and connected the wash brush. It has a surprisingly gentle rotating action that I doubted was doing much but apparently it was because I could easily spot areas I’d missed! 

Finally, I put the Vario Power spray back on (again on Medium, apparently Hard is too hard for cars) for a final rinse. It may sound like a lot of switching and faffing, but the job was complete in about 20 minutes, which is a lot less time than it takes to drive to the car wash and wait for somebody else to do the job. 

The results were on a par with the car wash too (except I didn’t bother with a chamois dry), and I saved a tenner in the process. Happy days all round. 

Is The Kärcher K4 Premium Power Control Pressure Washer Easy to Use?

Novices will find the Kärcher K4 Premium Control pressure washer very easy to get the hang of, especially with the step-by-step washing instructions on the App to hand. As well as car washing, it also gives guidance on cleaning bikes, paving slabs and other projects around the home and garden. 

The 5m power cable makes it easy to wheel the pressure washer around to complete bigger tasks — I added an outdoor extension lead to get power down to our driveway. 

If I had to complain, and I am scraping for issues here, I did find the high-pressure hose very stiff and prone to twisting and kinking, especially when moving around the car. It may well soften in use but trying to wind it onto the hose reel at the back when packing up was a herculean task. 

The availability of different power settings was very welcome, especially since the Kärcher K4 boasts some serious pressure. I’d advise extreme caution when washing paving slabs at full blast. Yes, you will eradicate all stains, lichen and other filth but it’s hard to avoid blasting away the grout between slabs in the process. 

Kärcher K4 Premium Power Control: Additional Features

The Kärcher K4 Premium Control pressure washer also comes with a foam dispenser attachment that allows direct detergent dispensing at the point of spray. I used the Plug n Clean system (via the mounting dock) instead but this would be a handy addition for anyone looking to use different detergents to those supplied by Kärcher. Those who use specialist products on their car, for example. 

Another feature I appreciated was the power indicator in the handle, which clearly showed, in a glance, which setting you were using. When the wrong pressure setting can cause havoc – for example the Hard setting has the potential to damage car tyres and blast render off of walls – so it’s good to feel in control.  

Extra accessories available to purchase include various brush options, spray attachments and hoses for suctioning water out of butts and troughs. 

How Easy is the Kärcher K4 Premium Power Control to Store?

As mentioned, the hose reel is almost impossible to wind in and there’s nowhere obvious to store the power cord but, with a little patience and muscle power, the pressure washer does pack away into a fairly compact unit. 

There are two handy racks to host the spray nozzles onboard and small storage net below. I am not sure what it is for, perhaps I could roll the cord and tuck it inside?

How Does it Rate Online?

On Kärcher’s own site, this particular model rates 4.5 stars out of 5, with customers loving the controllable pressure, patio attachment and awesome power. There was not a lot of love for the set-up instructions, which were described as woeful. Glad it wasn’t just me. 

Elsewhere online the plentiful reviews follow similar lines with the majority singing the praises of the Kärcher K4. Although I am not a pressure washer aficionado, these customer experiences largely met my own. Impressive in the main. This is a mid-range pressure washer in terms of price, and position in the Kärcher line-up but I find it hard to believe I am missing anything that would warrant paying more.  

About This Review and Our Reviewer

Linda Clayton is a long-established journalist working in the homes and interiors sector and has tested many products over the past 20+ years, including home tech, appliances, gym equipment, garden tools and even mattresses. Literally, paid to sleep! 

She lives in Devon with her husband and their two daughters, three dogs and one lonely budgie (free to a good home). Currently on her fourth, hopefully final, home renovation, she always has plenty of heavy-duty cleaning to do, much of it involving cement splashes and building debris, making her a great candidate to test the Kärcher K4 Premium Power Control pressure washer. 

She put it through its paces multiple times before writing this review, reporting on the three most relevant cleaning projects here to give an overall appreciation of its abilities.

We are not given any compensation by Kärcher for our reviews, but may be allowed to keep the product, meaning we can test it over a greater length of time, and update this review if required.