If you’re looking for a decent pressure washer to clean cars, bikes, patios and furniture, then the Karcher K4 and Karcher K5 are well-worth considering, but which is the best choice? Is the K5 worth the extra money?
In this article, I’ll directly comparing the Karcher K4 and K5 pressure washer models (and variants e.g. compact, power control, home etc.) so you can figure out which is the best option for you.
Karcher K4 vs K5 Summary
The Karcher K5 has a higher flow rate and maximum pressure rating in addition to a longer hose compared to the Karcher K4. Both models are similarly sized and come with two nozzles, a 5 meter mains cable and quick connect system. The K4 is cheaper than the K5 pressure washer.
| Specification | Karcher K4 | Karcher K5 |
| Maximum Pressure | 130 bar | 145 bar |
| Maximum Flow Rate | 420 litres/ hour | 500 litres/ hour |
| Motor | Air-Cooled on Compact and Water-Cooled on Power Control version | Water-Cooled on all versions |
| Hose Length | 6m for Compact and 8m for Power Control Model | 8m for Compact and 10m for Power Control Model |
| Compact Version Weight | 4.7 kg | 12 kg |
| Power Control Version Weight | 11.5 kg | 13.0 kg |
Still considering other Karcher models? Make sure you check out my guide to the Karcher pressure washer range to make sure you’re choosing the best option for your requirements.
Pressure and Flow Rate
Let’s start off with the most important specifications, flow rate and pressure, as these have the biggest impact on the performance of each device.
The Karcher K5 is a more powerful machine than the Karcher K4 as it has a higher maximum pressure rating and maximum flow rate. The Karcher K5 has a flow rate of 500 L/ hour and maximum pressure of 145 bar. The Karcher K4 has a flow rate of 420 L/ hour and maximum pressure of 130 bar.
This means the Karcher K5 produces 11.5% more pressure and has a 19% great flow rate in comparison to the less expensive Karcher K4 pressure washer.
Both machines are very powerful and capable of cleaning cars, outdoor furniture and patio flags. The extra power of the K5 can come in handy when cleaning patios and fences, but won’t make a huge difference when just cleaning a car.
The only time you’ll really notice a benefit of the increased pressure and flow rate of the K5 for car cleaning is when using a snow foam cannon, as this increased power will mean thicker foam is produced. However, it’s still possible to get very thick foam with a Karcher K4, especially if you’re using a good quality foam cannon.
Comparing Sizes
There are a few versions of the Karcher K4 and K5 which come in different sizes. The K4 has two variants: power control and compact. Whereas the K5 has three variants: power control, premium smart control and compact.
The K4 Compact model is the smallest followed by the K5 Compact model. The K4 Power Control is larger but slightly lighter than the K5 Compact. The K5 Power Control has the same dimensions but is heavier than the K4 Power Control.
The K5 Premium Smart Control is the heavier pressure washer and is slightly longer compared to the K4 and K5 Power Control models but it’s the same width and height.
Here are some tables to show the differences between each model in terms of their dimensions and weight.
Metric Units
| Karcher Model | Length | Width | Height | Weight |
| K4 Compact | 27.3 cm | 25.6 cm | 45.7 cm | 4.7 kg |
| K5 Compact | 35.4 cm | 30.8 cm | 52.0 cm | 12 kg |
| K4 Power Control | 40.2 cm | 30.6 cm | 58.8 cm | 11.5 kg |
| K5 Power Control | 40.2 cm | 30.6 cm | 58.8 cm | 13.0 kg |
| K5 Premium Smart Control | 41.4 cm | 30.6 cm | 58.8 cm | 13.9 kg |
Imperial Units
| Karcher Model | Length | Width | Height | Weight |
| K4 Compact | 10.7” | 10.1” | 18.0” | 10.4 lbs |
| K5 Compact | 13.9″ | 12.1″ | 20.5″ | 26.5 lbs |
| K4 Power Control | 15.8” | 12.0” | 23.1” | 25.4 lbs |
| K5 Power Control | 15.8” | 12.0” | 23.1” | 28.7 lbs |
| K5 Premium Smart Control | 16.3″ | 12.0″ | 23.1″ | 30.6 lbs |
Other Important Differences
As well as the K5 being a more powerful model compared to the K4, there are also a few other differences between the machines. The most notable being:
- The K5 has a aluminium telescopic handle whereas the K4 has a plastic telescopic handle.
- The K5 has a higher power rating of 2100W compared to the K4 which has a rating of 1800W so the K5 will use slightly more electricity.
- The K5 has a longer hose compared to the K4.
| Karcher Model | Hose Length (metric) | Hose Length (imperial) |
| K4 Compact | 6 meters | 19.7 ft |
| K5 Compact | 8 meters | 26.2 ft |
| K4 Power Control | 8 meters | 26.2 ft |
| K5 Power Control | 10 meters | 32.8 ft |
| K5 Premium Smart Control | 10 meters | 32.8 ft |
The 6 meter hose on the K4 Compact can be a bit limiting, and the 10 meter hoses found on the most expensive K5 Power Control and Premium Smart Control models in my opinion are a huge upgrade.
However, keep in mind that you can purchase higher quality and longer hoses on the aftermarket which I would recommend doing personally.
Model Variations (Compact, Home etc.)
There are several variations of the K4 and K5 models which can be very confusing.
Karcher K4 Variants:
- Compact
- Power Control
- Premium Power Control
The Compact model is lighter and smaller compared to the similarly sized Power Control and Premium Power Control. The main difference between the Power Control and Premium Power Control models is that the latter has an integrated hose reel. All models have the same pressure and flow rate.
Here is a table highlighting the other key differences.
| Karcher K4 Model | Hose Length | Motor | Detergent Application | Trigger | Integrated Hose Reel |
| Compact | 6 meter | Air-Cooled | Suction | Standard | No |
| Power Control | 8 meter | Water-Cooled | Plug and Clean | LED Display | No |
| Premium Power Control | 8 meter | Water-Cooled | Plug and Clean | LED Display | Yes |
Karcher K5 Variants
- Compact
- Power Control
- Premium Smart Control
The K5 Compact has an air-cooled motor which is not as durable as the water-cooled motor on the Power Control and Premium Smart Control models and it also has a shorter hose. The Premium Smart Control model is the only K5 with an integrated hose reel and Bluetooth compatibility which allows you to control the pressure washer using an app.
All models have the same pressure and flow rate and have a water-cooled motor.
| Karcher K4 Model | Hose Length | Detergent Application | Trigger | Integrated Hose Reel | Bluetooth Compatible |
| Compact | 8 meter | Suction | Standard | No | No |
| Power Control | 10 meter | Plug and Clean | LED Display | No | No |
| Premium Smart Control | 10 meter | Plug and Clean | LED Display | Yes | Yes |
Home and Car Versions
The only other variants that need to be addressed are the “home” and “car” models which are the exact same as the standard models but have extra accessories:
- Home: patio cleaner and detergent also included.
- Car and Home: patio cleaner and detergent, rotating car wash brush, foam jet and shampoo.
Whilst the “home” accessories can be quite useful, I strongly advise against using the car accessories.
These accessories are poor quality and the brush in particular will cause scratches in the paintwork. I always recommend using a microfiber wash mitt instead of a sponge or brush if you don’t want to ruin the car’s finish!
You can also find much higher quality foam cannons and car shampoos from dedicated car cleaning stores. Check out my car cleaning product recommendations if you’re looking for some suggestions.
Similarities Between the K4 and K5
- Two nozzles: the vario lance and dirt blaster lance.
- Quick connect on the machine for the hose.
- All models have a 5 meter main cable.
- The maximum water feed temperature is 40°C.
- The minimum pressure is 20 bar.
Specification Rundown
| Feature | K4 Compact | K4 Power Control | K5 Compact | K5 Power Control |
| Current Type | 230-240 V | 230-240 V | 230-240 V | 230-240 V |
| Minimum Pressure | 20 bar | 20 bar | 20 bar | 20 bar |
| Maximum Pressure | 130 bar | 130 bar | 145 bar | 145 bar |
| Max Flow Rate | 420 L/ hour | 420 L/ hour | 500 L/ hour | 500 L/ hour |
| Area Performance | 30 m2/ hour | 30 m2/ hour | 40 m2/ hour | 40 m2/ hour |
| Water Feed Max Temp | 40°C | 40°C | 40°C | 40°C |
| Power Rating | 1800 W | 1800 W | 2100 W | 2100 W |
| Power Cable Length | 5 meters | 5 meters | 5 meters | 5 meters |
| Hose Length | 6 meters | 8 meters | 8 meters | 10 meters |
| Weight (without accessories) | 4.7 kg | 11.5 kg | 12.0 kg | 13.0 kg |
| Dimensions (L x W x H) | 27.3 x 25.6 x 45.7 cm | 40.2 x 30.6 x 58.8 cm | 35.4 x 30.8 x 52.0 cm | 40.2 x 30.6 x 58.8 cm |
| Motor | Air-Cooled | Water Cooled | Water-Cooled | Water Cooled |
| Detergent Application | Suction | Plug and Clean System | Suction | Plug and Clean System |
| LED Display on Trigger | No | Yes | No | Yes |
| Telescopic Handle | Yes | Yes | Yes | Yes |
| Quick Connect on Machine | Yes | Yes | Yes | Yes |
Check out my complete guide to the Karcher pressure washer range to find out all the differences between each model.
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