There are plenty of good pressure washers around, but Kӓrcher is perhaps the best-known brand, with a reputation for high performance backed by solid German engineering. The company has been around since 1935, and experience like that is hard to beat.

Kӓrcher’s extensive range offers a variety of solutions from light domestic cleaning to heavy industrial scrubbing – there really is something for everyone. We've been looking at the pressure washers in depth so we can offer suggestions as to which models best suit particular needs.

Our top picks underline the broad choice available and feature everything from budget-friendly household models to machines for the most demanding professional. The shopping guide below contains more detailed information and answers to some common questions.

When you're trying to find the best Kӓrcher pressure washer, the key elements are power source, cleaning performance, and tips and nozzles.

You have a choice of plug-in electric or gas-powered washers. Your choice will depend on two considerations: convenience and performance.

Electric: Electric pressure washers are quiet and require little maintenance. The drawback is the restriction inherent in having a power cord. To many, that poses no problems, but 100 feet is the maximum with even the longest extension, which could be an issue if you have a large yard. For most homeowners, an electric pressure washer is probably more convenient.

Gas-powered: These pressure washers can be considerably more powerful than electric models and can go just about anywhere. However, they tend to be noisier, there's gas and oil to store and transport, and more maintenance is required. If you're cleaning on a professional scale, a gas-powered machine is probably the better choice.

The headline figure is usually pounds per square inch (psi), probably because big numbers are impressive! However, pressure is nothing without sufficient flow, so gallons per minute (gpm) is usually quoted as well. Karcher pressure washers range from 1,600 to 3,200 psi and from 1.25 to 2.5 gpm.

Some people are comfortable with what these figures mean, but others find them a little confusing. In order to provide a scale that makes it easier to make direct comparisons, the cleaning unit (cu) was introduced. It's calculated by multiplying the two figures together, for example:

• 2,000 cu rating: pressure of 1,600 psi x flow of 1.25 gpm
• 8,000 cu rating: pressure of 3,200 psi x flow of 2.5 gpm

A narrow jet of water at high pressure, with the right detergent, can clean deeply ingrained paint from concrete, but it would probably put a dent in your car's bodywork! The point is that you need different spray patterns for different jobs.

Most of Kӓrcher's consumer models have a fine Dirtblaster nozzle to deliver maximum pressure and precision, plus an adjustable Vario Power spray wand for general-purpose use. On some, the wand automatically dispenses detergent (when available) at a lower pressure setting. This is convenient if, for example, you're cleaning a vehicle. Use a higher pressure to remove a lot of the dirt, turn it down to apply detergent, turn it up again to rinse.

On more commercially focused pressure washers, Kӓrcher provides interchangeable nozzles. These are heavy-duty items designed to cope with the increased pressure. The result is a more defined set of spray patterns specific to certain tasks.

Detergent tanks: Some models have one or more built-in detergent tanks, while others have a siphon that draws liquid from a container you provide, which is useful when working with high volumes.

Storage: There’s usually a clip of some kind for the spray wand. Some models have additional storage bins for accessories.

Hose: Spray wand hose lengths range from 15 to 25 feet. Gas-powered Kӓrcher pressure washers have a side hook to keep the hose neat when it’s not in use. Some consumer models have hose reels so you only have to unwind the amount of hose you need rather than have an untidy heap on the floor.

Safety: As a safety feature, the motor doesn't run unless the trigger is pressed. On professional models, the triggers have child safety locks.

Wheels: The wheels on consumer machines are hard plastic, which is perfectly adequate, though they can crack if treated badly. On professional-grade Kӓrchers, we prefer to see pneumatic tires, which perform better on a variety of surfaces and are less prone to damage from knocks and bumps.

Accessories: You’ll find a wide variety of additional accessories for specific tasks: brushes for washing vehicles, cleaning heads for hard surfaces, and extra hose, for example. It might also be possible to fit third-party accessories, but the connectors aren't always universal, and some devices have maximum pressure ratings, so check before ordering.

All Kӓrcher pressure washers are guaranteed for two years, so we don't have to make our usual warning about cheap devices often being poor quality. While Kӓrcher pressure washers are definitely a premium product, they remain affordable.

Electric: The smart little K3 Follow-Me is a shade under $100, and the very capable K2 family of machines is around $20 more. The K5s will handle the toughest of household tasks, but the high-spec 540 with its water-cooled motor and built-in hose reel is still under $350.

Gas-powered: You might expect gas-powered Kӓrchers to be more expensive, but that's not the case. These powerful machines (2,200 psi to 3,000 psi) can usually be found for between $250 and $350.

• Soak, wash, rinse. The most efficient way to clean with a pressure washer is to soak the area first, then apply detergent or cleaning agent, and then rinse.
• Start with a wide spray angle. A fine jet at high pressure can cause damage. If you're using an adjustable wand, it's best to start with a wider spray angle, and adjust the concentration gradually until you get the power you need.
• Maintain the pressure washer per Kӓrcher guidelines. Electric pressure washers need little maintenance. Most problems are associated with blocked filters, so clean them regularly following the manufacturer's instructions. Gas engines need regular checks, but pressure washers are no more complex than a lawn mower.
• Wear safety goggles or a face shield when using the pressure washer. Dirt can dislodge at strange angles and at high speed.
• Never use a pressure washer from a ladder. The initial kick from the device can be powerful enough to make you slip.
• Never try to uncouple the hose or change wands or tips while the machine is running.

Kӓrcher offers a host of different pressure washing solutions, but even among its extensive range the K1700 Cube stands out. At just a foot tall, it's amazingly compact, yet it produces an impressive 1,700 psi. It's supplied with three nozzles, and you won't have to worry about bending down repeatedly – it's operated by a foot switch. The Karcher K2000 is a “prosumer” model – all the convenience of electric but with power that comes close to Kӓrcher's gas models. There's 2,000 psi on tap, four quick-change nozzles, twin detergent tanks, and a hose reel. A comprehensive choice for the toughest home-cleaning tasks.

Q. Do Kӓrcher pressure washers use a lot of water?
A. Water conservation is a real concern in many areas, so this is an important question. If you've been using an ordinary hose to clean your car, for example, then a Kӓrcher pressure washer should actually save water. The flow rate of a garden hose on a typical household supply is around 800 gallons per hour. Kӓrcher's consumer-rated pressure washers run at between 60 and 160 gallons per hour. Because of the greater pressure, they also clean more efficiently. You'll get the job done more quickly, which reduces the amount of water used even further.

Q. Can I spray bleach using a pressure washer?
A. No. Never. Bleach can do serious damage to the seals inside the machine's pump, likely leading to expensive repairs. You shouldn't spray bleach anyway – it's dangerous to your airways and lungs, and any overspray will kill plants and cause random damage.

If you have problems with mold and fungus, try a solution of three parts water to one part white vinegar. It's not poisonous, but some find the vapor a little unpleasant, so wearing a lightweight face mask is a good idea.

Q. Is it safe to use a pressure washer to clean my car? I've heard the device can damage paint.
A. Too much pressure does have the potential to damage vehicle paint, but it's easily avoided. Automotive experts recommend keeping the pressure below 1,800 psi. While some Kӓrcher pressure washers can exceed this, those aimed at home use do not. If you're using a commercial-grade device, turn the pressure down and use a wide-angle nozzle.