Kärcher K4 Full Control review: Can Kärcher’s pressure washer clean up in a competitive market?

Whatever you use your outdoor space for – parking your car, hosting barbecues, discarding your muddy boots – it’ll need to be cleaned every now and then. While that sounds like a dreadful bore, the task becomes considerably less arduous and even, dare I say it, fun when you use a high-powered pressure washer such as the Kärcher K4 Full Control.

At £165, the K4 Full Control is not what you’d consider an impulse purchase, but with impressive power and a choice of attachments for managing different tasks, it’s a great option for cleaning your patio, car or wheelie bin, and everything in between.

Covid-19 update: Following the government lockdown and the fact spring has well and truly sprung, everyone’s had the same idea and rushed out to buy pressure washers. As such, it’s difficult to find the excellent Karcher K4 Full Control still in stock online. At the time of writing, it’s still available for delivery from Cycle Republic for just £180. If when you’re reading this, that’s no longer the case, we’d recommend referring to our best pressure washer roundup, which we’ll keep up to date with the best pressure washers that are currently in stock.

Kärcher K4 Full Control review: What you need to know

Kärcher has an enviable pedigree when it comes to cleaning. Not only is its founder Alfred Kärcher credited with inventing the hot-water high-pressure washer in 1950, but the German firm has also scrubbed over 140 monuments worldwide since 1980, including Berlin’s Brandenburg Gate and the Christ the Redeemer statue in Rio.

Positioned around the middle of its extensive pressure washer range, the 1,800W K4 Full Control is marketed by Kärcher as the best choice for cleaning medium-sized patios and cars. It delivers pressures from 20 to 130 bar, and promises to clean up to 30 square metres per hour.

For comparison, Kärcher’s entry-level K2 Full Control, which is rated at 110 bar, is recommended only for removing dirt on bicycles, garden tools and garden furniture. The top-of-the-range K7 Full Control Plus Home, meanwhile, delivers up to 180 bar of pressure and cleans up to 60 square metres per hour.

^The K4 Full Control Home variant

The K4 Full Control comes with two spray lances: the Vario Power, which can be adjusted from low to high pressure by simply turning the lance, and the Dirt Blaster, which is intended for use on particularly stubborn dirt. If you need the very best performance when cleaning your patio or decking, you can opt to buy the K4 Full Control “Home” variant, which comes with an additional T350 patio cleaner and a bottle of detergent.

The K4 Full Control comes with a three-year warranty.

Kärcher K4 Full Control review: Price and competition

Kärcher’s K4 Full Control costs £165, while the K4 Full Control Home model will set you back £210. Neither model comes with any additional accessories such as brushes and foam jets, but these are available to buy from Kärcher.

Although it represents reasonable value, similarly well-powered pressure washers from other brands are available for less. B&Q’s Mac Allister 1,800W, for instance, costs around £40 less (£128) and comes with two brush attachments.

Even cheaper is the 1,700W Bosch AQT 37-13+ at £125, which offers 130-bar pressure and a 3-in-1 nozzle, patio cleaner and brush attachments.

Kärcher K4 Full Control review: Design and features

If you’re the sort of person who cares what their garden implements look like, you shouldn’t be disappointed by the K4 Full Control. Kärcher has won design awards for its products, and the K4 Full Control is both compact and colourful.

An LED display atop the trigger gun enables you to easily identify how much pressure you’re using, and you can adjust this by simply twisting the Vario Power spray lance. That’s a neat touch, but I was arguably more impressed by the connector that attaches the hose pipe to the machine. When I attempted to carry out this simple task on B&Q’s Mac Allister 1,800W pressure washer, the connector shattered into pieces as soon as I turned on the water tap.

That might have partly been my fault for not screwing it on properly, but I still wouldn’t expect it to cave in under the pressure. Never once did I fear that the Kärcher’s sturdy nozzle would suffer a similar fate.

Another boon with the K4 Full Control is the height-adjustable handle, which enables you to pull it with ease, no matter how long your arms are. It might not sound like a big deal, but the same luxury isn’t available on the Mac Allister 1,800W.

And, if you don’t have a tap nearby, the pressure washer can be used with a bucket or water butt if you buy Kärcher’s additional suction hose and filter accessory for £21. If you’re planning to improve its cleaning performance with warm water, though, it’s worth noting that the K4 will only work with water up to 40˚C.

Kärcher K4 Full Control review: Cleaning performance

To find out how well the K4 Full Control cleans, I first opened my dishwasher and reached for a porridge-caked saucepan. Obviously, you won’t be using the washer to clean your pots and pans, but my reasoning was that if it could obliterate this oat-based monstrosity, it should cope with most things.

After removing the Full Control trigger gun from its handy dock, I attached the Vario Power spray lance. I twisted this until the LED screen on the handle informed me that I was in “hard” wash mode (there’s also a “medium” mode for car washing and a “soft” mode for cleaning more delicate materials such as wood, and a “detergent” mode for when you want to use more than just water pressure alone).

No sooner had I pulled the trigger than the K4 Full Control began eating into the porridge. After a short time, the pan looked almost new. I later deployed the Mac Allister 1,800W on a separate saucepan and, while it created a similarly impressive storm of white goo, it did leave behind a few stubborn scabs.

Onwards to the patio, which hadn’t been maintained since we moved in eight years ago (I know, I know). For this task, I connected the T350 patio cleaner that comes with the Full Control Home model. Its improved patio-cleaning performance can be attributed to its twin rotating water jets, which work their magic beneath a circular shell to create a satisfying hovercraft effect as you glide it across the paving – perfect for dealing with uneven surfaces. The shell also serves to prevent splashback and, with the K4 Full Control easily pulling up the algae with each sweep, there was certainly plenty of that.

Finally, I attached the Dirt Blaster spray lance. To test its capabilities, I focused on my patio table, whose mosaic stone surface has accumulated all manner of detritus over the past few years. Within seconds, the high-powered jet had loosened the grime from the cracks between the stones, and a minute or two later the whole table was gleaming. While I enjoyed using the Dirt Blaster, it didn’t seem much more powerful than the “hard” setting on the Vario Power spray lance. If I owned this pressure washer, I think I’d be inclined to keep the Vario Power attached permanently, and simply adjust it to suit whichever job I needed to do.

A quick word about the K4 Full Control’s sound output. Much has been made of the din produced by pressure washers, but this one creates a warm, satisfying hum, almost like a biplane. In other words, I was in no hurry to switch it off.

Kärcher K4 Full Control review: Verdict

There’s no doubt that you’re paying extra for the name – along with a few nice design touches – but Kärcher’s K4 Full Control can perform the majority of outdoor cleaning jobs with aplomb. Whether you want to return your patio slabs to their original shade or eliminate seagull slurry from your conservatory roof, it’ll do it with ease.

If you’re on a strict budget, though, its rivals from Mac Allister and Bosch deliver broadly comparable performance and more accessories for less money. That’s worth consideration, but if paying extra isn’t a problem for you, the K4 Full Control offers best-in-class build quality and can easily be enhanced with a range of accessories.