Buy the K4 Power Control Flex unless the drive is long or green. Same gun, same Vario, same Plug ‘n’ Clean bottle. The K5 adds water volume, two extra metres of hose and 15 bar. That is a driveway upgrade, not a different way of washing a car. We keep saying this because shops will happily sell you the bigger number.
The K4 we mean is £169 on 22 August 2026: 130 bar, 420 L/h, 8 m Flex hose. The K5 we mean is £339.99: 145 bar, 500 L/h, 10 m Flex. If those prices move, check the live tile. The decision does not. Cars and a normal patio stay on the K4. A 30 to 40 m² north-facing frontage moves to the K5.
If you click through and buy, we may earn a commission.
The rest of the range sits on the Kärcher hub. If you are still between a K2 and a K4, see K2 vs K4.
Quick picks
Best for most homes
K4 Power Control Flex
£169
130 bar, 420 L/h, 8 m Flex hose. The Kärcher most UK households should start with.
Best if the patio is part of it
Kärcher K4 WCM Flex eco!Booster Home
£229
Max 130 bar Home kit with a T-Racer in the box.
Best for a long drive
K5 Power Control Flex
£339.99
145 bar, 500 L/h, 10 m hose. Same car-safe Vario. Buy it for litres and reach, not for extra punch on paint.
Comparison table
| K4 Power Control Flex | K5 Power Control Flex | |
|---|---|---|
| Max pressure | 20 to 130 bar | 20 to 145 bar |
| Flow | 420 L/h | 500 L/h |
| Area (Kärcher figure) | 30 m²/h | 40 m²/h |
| Hose | 8 m PremiumFlex | 10 m PremiumFlex |
| Motor | 1.8 kW, water-cooled | 2.1 kW, water-cooled |
| Weight (bare) | about 12 kg | about 12.4 kg |
| Home kit head | T 5 plus stone cleaner | T 5 plus stone cleaner |
| Typical UK price, 22 Aug 2026 | £169 | £339.99 |
Home and Car & Home boxes cost more. Confirm the T 5 is in the carton before you add one separately.
Who should buy which
Buy the K4 if you have a tap, a 13A socket, one or two cars and a normal UK patio. 130 bar with a twist-to-adjust Vario is the useful home class. Eight metres of Flex hose walks a family hatchback if you park the trolley at a corner.
Buy the K5 only if the drive is long or green, or you are already tired of dragging a shorter hose halfway down the path. 500 L/h rinses shampoo and stone cleaner faster. Ten metres means you park the machine once. That is the whole upgrade.
Buy a Home kit only if you do not already own a T 5 and you will use one. A T 5 on its own is from about £55. Bare Flex plus a separate head is often close to a Home box. Shop the live total.
Skip both if there is no outdoor socket or no tap. That is a cordless job, not a bigger K-class. Start with the cordless guide.
Kärcher K4 Power Control Flex
The default Kärcher for a UK home
- 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: cars, bikes, furniture and a normal patio
This is the machine most people who type K4 vs K5 should take home. The LED on the gun shows the pressure step. Drop it for paint and glass. Open it for arches and stone. The dirt blaster is for paving, not lacquer. Leave it on the hook when the car is out. Buy the Flex, not an older stiff-hose K4. Eight metres is enough for a hatchback on a short drive. It is not enough to stand still on a long van.
Paint distance sits on the cars page.
Skip it if the driveway is long and green. That is the K5. Skip it if you only rinse one small car and will never touch the slabs. A K2 will do that for half the money.
Kärcher K4 WCM Flex eco!Booster Home
The K4 to buy if you also want the patio head
- Buy: Amazon Home listing £229
- In the box: the K4 Flex, T 5, 1 L stone cleaner, Vario, dirt blaster, 8 m Flex hose
Home means a T 5 in the carton, not a different pump. Same 130 bar as the bare Flex. Do not then add a second T 5. If the Flex is £169 and the head is £55, the WCM Home kit at £229 is the patio carton. Shop the contents list. Heads sit on the patio cleaner page.
Skip it if you already own a working K4. Buy the T 5 on its own. Skip it if the patio is large, north-facing and filthy. That is the K5 kit.
Kärcher K5 Power Control Flex
The Kärcher to buy if the drive is part of the job
- Buy: Check latest price £339.99, in stock · GO Outdoors £339.99
- Pressure / flow: 20 to 145 bar, 500 L/h
- Hose: 10 m PremiumFlex
- Who it is for: cars plus a long or green drive
Same gun, same Vario. The upgrade is litres and hose. 500 L/h rinses faster. Ten metres means you park the trolley once. 145 bar on a wide fan, a metre back, is fine on modern paint. As a pencil jet it will cut lacquer. The extra bar is for block paving, not for standing closer.
£339.99 is the named street price on this check. The first figure on that page is excluding VAT. Amazon’s old street around £240 is gone. Buy Power Control Flex if you want the gun that shows the step and the 10 m Flex hose. Buy Classic if you only want K5 water volume and the live price is clearly lower.
Skip it if the only job is cars and garden furniture. Keep the K4 and spend the difference on a foam jet.
Kärcher K5 Power Control Flex
The K5 kit if the patio is big as well
- Buy: Amazon Home listing £339.99
- In the box: K5, Power Control gun, Vario, dirt blaster, 10 m Flex hose, T 5, 1 L stone cleaner
Same T 5 as the Kärcher K4 WCM Flex eco!Booster Home box. The upgrade is still water volume and hose, not a better patio head. The K5 Flex is £339.99. A T 5 on its own is still about £55 if you already own the washer.
Skip it if the only hard surface is a 3 × 4 m yard. The Kärcher K4 WCM Flex eco!Booster Home is enough.
Cars versus driveway
A car does not need 145 bar. It needs a wide fan, distance, and enough hose to walk around the body without yanking the trolley. Both machines will wash a car if you stay on the Vario. Kärcher’s own advice is a flat jet, at least 15 cm from paint and 30 cm from tyres. Further is safer.
The K5 earns its keep on the drive, not on the bonnet. If the only hard surface is a short path and a parking bay, the K4 is the rational car washer. Foam is worth more than another 15 bar on paint.
How to choose
- Cars and a normal patio, one machine. K4 Power Control Flex, or the Kärcher K4 WCM Flex eco!Booster Home if you do not own a T-Racer.
- Cars plus a long or green drive. K5 Power Control Flex.
- Patio only, already own a K4 or K5. Buy the T 5, not another washer.
- Tight budget, one small car, no slabs. See K2 vs K4.
- No socket or no tap. Cordless. Not a K5.
Flex means the PremiumFlex hose. Power Control means the gun shows the step. Home means the T 5. Shop the carton, not the word K5 on a tile.
FAQ
Is the K5 worth the extra money over the K4?
Only if you will use the extra flow and the 10 m hose. At £339.99 the step from a £169 K4 is about £171. That is a lot for 15 bar on a car. It is reasonable for a long, green drive you do twice a year.
Can I wash a car with a K5?
Yes, on a wide Vario setting, at a distance. Do not use the dirt blaster on lacquer. The extra bar is not a reason to stand closer.
Do I need a Home kit?
Only if you do not already own a T 5 and you will use one. Bare Flex plus a separate head is often close to a Home box.