Kärcher buying guide
Kärcher makes buying a pressure washer harder than it needs to be. There are four or five cartons of the same machine on any given shelf, all yellow, all covered in words like Flex, Home, Premium and Power Control, and none of it tells you plainly which one you want.
Here’s the short version. The number after the K is the pump class, and that’s the bit that decides how much cleaning the machine can do. Flex tells you about the hose. Home tells you a patio head is in the box. Everything else on the tile is marketing. Get the pump class right first, then pick the carton that has the accessories you’ll actually use. Here’s how we review.
Which Kärcher suits your place?
| Your situation | Buy | Why |
|---|---|---|
| A house with a tap and a 13A socket, one or two cars, furniture, a normal patio | K4 Power Control Flex | The default. Enough pump for everything on that list without paying K5 money |
| All of the above plus a 30 to 40 m² drive that goes green | K5 Power Control Flex | 500 L/h and 10 m of hose are what finish a drive in one session |
| One small car and a couple of chairs, and that’s genuinely it | K2 Home | Cheapest way in, as long as you’re honest about the job list |
| No outdoor tap, or no outdoor socket | OC 6-18 Premium | The only cordless Kärcher worth your money, and only in this situation |
- K4 Power Control Flex
- K5 Power Control Flex
- K2 Home
- OC 6-18 Premium
- Full comparison
- K7, heads and petrol
- FAQs
Best Kärcher pressure washers at a glance
Kärcher K4 Power Control Flex
130 bar, 420 L/h and 8 m of PremiumFlex hose, with a water-cooled motor built for full sessions. The one most UK houses should buy.
Kärcher K5 Power Control Flex
145 bar, 500 L/h and 10 m of hose. The flow rate, not the pressure, is what gets a driveway done in an afternoon.
Kärcher K2 Home
110 bar, 360 L/h and a 4 m hose, with an air-cooled motor meant for short bursts. Fine for one car, out of its depth beyond that.
Kärcher OC 6-18 Premium
24 bar and 200 L/h from a 12 L trolley on a battery. The answer when there’s no tap or no socket, and only then.
Kärcher pressure washers compared
Read across the pump class first. Pressure tells you what the machine can lift off a surface, flow rate tells you how fast it carries it away, and hose length decides how often you stop to move the thing.
| Model | Best for | Pressure | Flow | Hose or tank | Price |
|---|---|---|---|---|---|
| K4 Power Control Flex | Most UK houses | 20 to 130 bar | 420 L/h | 8 m PremiumFlex | £169 |
| K5 Power Control Flex | Cars plus a drive | 20 to 145 bar | 500 L/h | 10 m PremiumFlex | £339.99 |
| K2 Home | One small car | 20 to 110 bar | 360 L/h | 4 m | £147.98 |
| OC 6-18 Premium | No tap or no socket | 24 bar | 200 L/h | 12 L trolley | £229.99 bare |
| K2 Horizontal | Tiny tap-fed jobs | The cheapest way into the range, and the least machine in it | £59.99 | ||
1. Kärcher K4 Power Control Flex: the best Kärcher for most homes
If you take one thing from this page, take this: the K4 Flex is the default UK house buy. 130 bar and 420 L/h is the point where the machine stops being the limiting factor on cars, furniture and a normal patio, and the water-cooled motor is built to run for a full session rather than in short bursts. That last bit is what separates it from the K2 more than the pressure figure does.
The 8 m PremiumFlex hose stays soft in cold weather instead of springing back into coils, and the Vario control on the gun lets you change pressure at the trigger rather than walking back to the machine. Wind it down for a painted bench, wind it up for block paving, no lance swapping.
There’s a Home version of the same machine at £229 with a patio head and cleaner in the box. Identical pump, so it’s an accessory decision rather than a different pick. Our full K4 review works through which carton to get.
Buy it for
- A house with an outside tap and a 13A socket
- Cars and garden furniture
- A normal UK patio
Skip it if
- There’s a long green drive, where the K5 does the work in less time
- The whole job is one tiny car, where the K2 is enough
2. Kärcher K5 Power Control Flex: best if the drive is part of the job
The K5 gains 15 bar over the K4, and that is not why you’d buy one. The reason is 500 L/h against 420 and 10 m of hose against 8. More water per minute means more green lifted and carried away per pass, and 2 m of extra hose means fewer stops to drag the machine to a new spot. On a 30 to 40 m² drive that adds up to finishing in one go instead of stretching it across a weekend.
The gun is the same, so nothing changes about how it feels in the hand. What does change is the price, and at twice the K4 it only makes sense when there’s genuinely a drive involved. Buying a K5 to get closer to a car is money wasted, and the extra pressure is the last thing paintwork needs. Our K4 vs K5 comparison and the K5 review go deeper, and the driveway guide covers surface cleaners.
Buy it for
- Cars plus a 30 to 40 m² drive
- 500 L/h, which is the real upgrade over the K4
- 10 m of hose on bigger, more spread-out jobs
Skip it if
- It’s cars and chairs only, in which case keep the K4 and the difference
3. Kärcher K2 Home: the budget Kärcher
At about 4 kg the K2 is the one you can carry out with one hand and put away without thinking, and 110 bar is plenty for a supermini and a set of chairs. The air-cooled motor is the honest limit. It’s designed for short bursts, not for an afternoon on the paving, and a 4 m hose means you’re moving the machine constantly on anything larger than a car.
The T 1 head in the Home box tells you what Kärcher expects you to do with it. It’s a small patio head and it takes a long time on anything bigger than a doorstep, which is a different proposition from the bigger heads that come with the K4 Home carton. There’s also a K2 Horizontal at £59.99 if you want the absolute cheapest way in for tiny tap-fed jobs, though it’s less machine again.
Be honest about the job list before you buy. If the patio is going to get done even twice a year, the K4 now beats replacing this in eighteen months. See K2 vs K4 and the K2 review.
Buy it for
- One small car
- Light garden furniture
- A machine light enough to carry in one hand
Skip it if
- You’ll take on the drive or patio twice a year, in which case buy the K4
4. Kärcher OC 6-18 Premium: the only cordless Kärcher worth buying
This is the one cordless Kärcher we send people to, and only in one situation: there’s no outdoor tap, or no outdoor socket, or neither. Fill the 12 L trolley indoors, wheel it out and you’ve got 24 bar and 200 L/h wherever you need it. If you’re already running Kärcher 18V Battery Power packs from a hedge trimmer or a window vac, it costs you £229.99 and nothing else.
Two things to be clear about. This is not a battery K 2, and expecting mains-class cleaning from 24 bar will disappoint you. It’s also a different thing entirely from the OC 3 family, which are 5 to 6 bar rinsers rather than pressure washers, so don’t let a similar-looking box on the shelf catch you out. Our OC 6-18 review has the detail, and the cordless hub covers what else is out there.
Buy it for
- No outdoor tap, no outdoor socket, or both
- Anyone already on Kärcher 18V Battery Power
- Bikes, kit and a rinse where a lead can’t reach
Skip it if
- You have a tap and a socket, where the K4 does far more for less
K7, patio heads and the petrol range
You almost certainly don’t need a K7
The K7 sits in the 180 bar class, and it exists for large plots rather than for a nicer car wash. If your land is measured in acres and you’re cleaning long runs of hard standing, it earns its keep. On a normal drive it’s more machine than the job needs, and on paintwork you’d be winding it down so far that you’ve paid for pressure you can’t use. Our K5 vs K7 comparison covers where the line actually sits.
The head matters more than the next K number
If you’ve already got a K4 and the patio is slow going, a bigger patio head will change your afternoon far more than trading up to a K5 would. A proper head covers a wide strip at a consistent distance and keeps the spray under a shroud instead of over your shoes. The patio head guide runs through the sizes, and our how to use one walkthrough covers technique, which is free.
Petrol is a different decision entirely
Kärcher does build petrol machines in its Professional range, and they’re aimed at trade users and sites with no power rather than at homeowners who want more grunt. If there genuinely isn’t a socket and the plot is big, that’s a conversation worth having, but start with our petrol guide rather than assuming the yellow badge makes it the right buy.
Don’t shop the badge on the tile. Power Control, Premium, Flex, Home and Smart Control all describe the box, not the pump. Two machines with completely different cleaning ability can carry most of the same words. Find the K number, check the bar and the litres per hour, then look at what’s in the box.
Kärcher pressure washer FAQs
Which Kärcher pressure washer should I buy?
The K4 Power Control Flex at £169 for most UK houses. It has 130 bar, 420 L/h, an 8 m hose and a water-cooled motor, which covers cars, furniture and a normal patio. Go up to the K5 only if there’s a driveway, drop to the K2 only if the job really is one small car.
What do the K numbers actually mean?
The number after the K is the pump class, and it’s the only part of the name that tells you how much cleaning the machine can do. K2 is 110 bar and 360 L/h, K4 is 130 bar and 420 L/h, K5 is 145 bar and 500 L/h. Get that number right first and worry about the rest of the name afterwards.
What does Flex mean on a Kärcher?
It refers to the hose. A Flex carton comes with PremiumFlex hose, which stays supple in cold weather rather than curling back into coils every time you put the gun down. It says nothing about the pump, so a K2 Flex and a K5 Flex are still very different machines.
What does Home mean on the box?
A patio head is included. That’s the whole difference. The pump is the same as the standard carton, so the question is simply whether you want a head in the box or would rather buy one later. Watch the size, though: a K2 Home ships with the small T 1, not the bigger heads you get in a K4 Home carton.
K4 or K5?
K4 unless there’s a driveway. The 15 bar difference is not the point. You’re paying for 500 L/h against 420 and 10 m of hose against 8, and that only pays back across a 30 to 40 m² drive. For cars and a patio, the K4 does the same work for roughly half the money.
Is the K2 enough?
For one small car and light furniture, yes. Beyond that, no. It’s 110 bar and 360 L/h with a 4 m hose and an air-cooled motor designed for short bursts, so a long session on paving is not what it’s for. If the drive or patio is on your list even occasionally, buy the K4 instead.
Is there a cordless Kärcher worth buying?
The OC 6-18 Premium, and only when there’s no outdoor tap or no socket. It gives you 24 bar and 200 L/h from a 12 L trolley on an 18V pack. It isn’t a battery version of a K 2, and it’s a different product from the OC 3 range, which are 5 to 6 bar rinsers.
Do I need a K7?
Almost certainly not. The K7 is in the 180 bar class and it’s built for large plots. On a normal driveway it’s more pressure than the job needs, and on a car you’d have to wind it right down anyway. If you’re weighing it up against a K5, the plot size is the deciding factor, not how clean you want the car.
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