The K2 is an occasional washer. The K4 is the house buy. If you will wash a car and the slabs, take the K4 Power Control Flex at £169 and stop shopping the yellow 110 bar boxes. We only send you to a K2 if the job is one small car, garden furniture, and you will accept a short hose.
The K4 is the first Kärcher that behaves like a household machine: water-cooled motor, 8 m Flex hose, a gun that shows the pressure step, and enough flow to run a proper patio head. The K2 is 110 bar, 360 L/h, an air-cooled motor and 3 to 5 m of hose. Fine four times a year. Thin every weekend. Street prices checked 22 August 2026. The K2 Home is £147.98.
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The rest of the range sits on the Kärcher hub. A long, green drive is K4 vs K5, not this page.
Quick picks
The one to buy
K4 Power Control Flex
£169
130 bar, 420 L/h, 8 m Flex hose. The real household step-up from a K2.
Best if the patio is the job
Kärcher K4 WCM Flex eco!Booster Home
£229
Max 130 bar Home kit with a T-Racer in the box.
Best budget K2
K2 Home / Power Control
£147.98
110 bar, 4 to 5 m hose, about 4 kg. Fine for one small car. Not a driveway machine.
Cheapest Kärcher still sold
K2 Horizontal / Classic
£59.99
Same 110 bar class, 3 m hose. Still sold. Buy it only if the job is furniture and a bike.
Comparison table
| K2 class | K4 Power Control Flex | |
|---|---|---|
| Typical UK boxes | Power Control, Home, Classic, Horizontal | Bare Flex, Home |
| Max pressure | 110 bar | 20 to 130 bar |
| Flow | 360 L/h | 420 L/h |
| Hose | 3 m Horizontal / Classic, 4 m Screwfix Home, 5 m on many Power Control kits | 8 m PremiumFlex |
| Motor | 1.4 kW, air-cooled | 1.8 kW, water-cooled |
| Weight | about 4 kg | about 12 kg |
| Patio head in Home kits | T 1 (small) | T 5 |
| Honest job | One small car, furniture | Cars, furniture and a normal patio |
| Typical UK price, 22 Aug 2026 | £147.98. Classic about £85 | £169. Home £229 |
K2 kits multiply. The number is the pump class, not the kit name. Confirm what is in the box.
Who should buy which
Buy the K4 if you already know you will wash a car and the slabs, or if you hate short hoses. That is most UK households shopping this comparison in good faith.
Buy the K2 if the budget is tight, the only job is one small or medium car plus light furniture, and you will not also take on a mossy drive. Accept the short hose and the air-cooled motor.
Do not buy a K2 Home as a patio machine. The head in that box is a T 1, not a T 5. Fine for a tiny yard. Thin on a green terrace. If the patio is the main job, buy a Kärcher K4 WCM Flex eco!Booster Home.
Skip both if there is no outdoor socket or no tap. Start with the cordless guide.
Kärcher K4 Power Control Flex
The real household Kärcher
- Buy: Check latest price £169
- Pressure / flow: 20 to 130 bar, 420 L/h
- Hose: 8 m PremiumFlex
- Motor: 1.8 kW, water-cooled
- Who it is for: one machine for cars, bikes, furniture and a normal patio
This is the step-up. 130 bar with a twist-to-adjust Vario is the useful UK class for paint and stone. The LED on the gun shows the step, so you are not guessing. Eight metres of Flex hose walks a family car if you park the trolley at a corner. The water-cooled motor is quieter and happier in a long session than the K2’s air-cooled unit. The dirt blaster is for stone, not lacquer.
If the drive is long and filthy, the next step is a K5, not a second K4. That comparison is on K4 vs K5.
Skip it if you only rinse one small car a few times a year and you will never touch the slabs. The K2 will do that for about half the money.
Kärcher K4 WCM Flex eco!Booster Home
The K4 if you also want the patio head
- Buy: Amazon Home listing £229
- In the box: K4 Flex, T 5, 1 L stone cleaner, Vario, dirt blaster, 8 m Flex hose
Home on a K4 means a T 5. That is the everyday 280 mm hood. It is not the small T 1 that ships in a K2 Home box. Do not then buy a second T 5. If the Flex is £169, the Kärcher K4 WCM Flex eco!Booster Home at £229 is a small premium. Shop the live total.
Skip it if you already own a working K4. Buy the head on its own.
Kärcher K2 Power Control and Home
The budget Kärcher, if you are honest about the job
- Buy: Check latest price £147.98
- Pressure / flow: 20 to 110 bar, 360 L/h
- Hose: 4 m on the Screwfix Home box, 5 m on many Power Control kits
- Motor: 1.4 kW, air-cooled
- Who it is for: one small or medium car, light furniture
110 bar is enough to wash a car if you foam first and stay on the Vario’s wide setting. It is not enough to pretend this is a patio machine. The short hose is the daily frustration. You will drag the trolley around the car. The air-cooled motor is louder and less happy in long sessions than the K4.
K2 kits multiply. Same 110 bar class, different hose and extras. The Screwfix Home box includes a T 1, not a T 5. Fine for a balcony. If you already know you will do the drive twice a year, buy the K4.
Skip it if you have two cars, a long hose run, or you want a gun that shows the pressure step on an 8 m Flex hose.
Kärcher K2 Horizontal and Classic
Still sold. Still a light machine.
- Buy Horizontal: Kärcher UK, typically £59.99
- Buy Classic: Screwfix K2 Classic around £85
- Hose: 3 m
- Who it is for: bikes, tools, a chair, a buyer who will store it on a shelf
The Horizontal is the compact box. The Classic is the small upright. Same 110 bar class. The hose is three metres: a bike and a bench, not a car you walk around. If the job has grown past furniture, the K4 is the buy.
Skip it if you will wash a car every weekend. The hose will annoy you on day one.
The T 1 mistake
A K2 will wash a car. Stay on the wide Vario, keep your distance, foam first. It will not match a K4 for a weekly family wash. The short hose is why. A K2 will spin a T 5 if you buy one separately. It will feel thin on a green terrace. 110 bar and 360 L/h move the head. They do not strip a winter of algae the way a K4 does. Shops still sell the K2 Home box as a patio kit. It is a small-yard kit.
If the patio is the main job, buy the Kärcher K4 WCM Flex eco!Booster Home. If you already own a K2 and the slabs have gone green, the honest upgrade is a K4, not a £55 head on a weak pump. The T 7 Plus is K4 to K7 only. A K2 cannot run it.
How to choose
- One small car, furniture, tight budget, no slabs. K2 Home or Power Control. Accept the hose.
- Furniture and a bike only. Horizontal or Classic, if the price is £59.99.
- Cars and a normal patio. K4 Power Control Flex, or the Kärcher K4 WCM Flex eco!Booster Home if you do not own a T-Racer.
- Long or filthy drive. Skip this page. See K4 vs K5.
- No socket or no tap. Cordless. Not a bigger K2.
Power Control on a K2 is a nicer gun than Classic, not a different pump class. Flex on a K4 is the hose you want. Home means a patio head. On a K2 that head is small. On a K4 it is a T 5. First-use setup sits on how to use a pressure washer.
FAQ
Is the K4 worth twice a K2?
If you will do cars and stone, yes. The K4 is not twice the bar. It is a longer hose, a water-cooled motor and a patio head that actually matches a UK terrace. If you will only rinse a Fiesta four times a year, no.
Can a K2 clean a driveway?
Slowly, and only if the dirt is light. A green, neglected drive is a K4 or K5 job. Putting a T 5 on a K2 does not turn it into a K4.
Is the K2 Horizontal still sold?
Yes. Kärcher UK still lists it. The live compact alternative is usually the K2 Classic, same 110 bar class, 3 m hose.
Will K4 accessories fit a K2?
Most Home & Garden bayonet lances and the T 5 will clip onto a current K2 gun. The T 7 Plus will not.