Features

• The main part of a pressure washer is the pump. This generates the necessary pressure for the water and feeds it down a hose to a spray wand with an on/off trigger. The end of the wand has an adjustable nozzle that controls the fan of the spray according to the cleaning task at hand. A wider spray of 20 to 25 degrees will wash a larger area, but with less cleaning power. By contrast, a zero-degree spray will provide dangerously intense cleaning power that can remove paint.
  
  

Function

• Pressure washing works by propelling water at a tremendous force, which breaks the bond between the dirt and the object or surface being cleaned. To get an idea of the power it exerts, consider that a standard garden hose delivers water at around 40 PSI (pounds per square inch). Multiply that by 100 and you get an idea of the pressure generated by high-powered pressure washers. It should be noted, however, that the PSI rating is not the only factor in calculating cleaning power; the water flow (calculated in gallons per minute) is also critical to the washer's effectiveness.
  
  Cleaning units (CUs) are the way to determine the effectiveness of a pressure washer, and the value is calculated by multiplying the PSI value by the water flow. As an example, a PSI rating of 1,800 with a water flow of two gallons per minute would yield a CU rating of 3,600. Most medium-duty cleaning jobs such as the cleaning of lawn furniture, decks and sidewalks can be accomplished with a rating of between 3,000 and 5,000 CUs.
  
  Many pressure washers also come with a detergent tank so cleaning agents can be sprayed onto the area, making the units even more efficient. The detergent is sprayed on at very low pressure (much like the soap at a car wash) a left for a while to emulsify the dirt to make it easier to remove with the high pressure spray.
  
  

Types

• The two main types of pressure washers are electric and gas-powered. The power rating of electric models is measured in amps, while the gas models are measured in horsepower. The smaller, less powerful models that offer a pressure rating of between 1,000 and 2,000 PSI, are usually electric models. Although less powerful, these are generally strong enough for cleaning most household items, like garden furniture, fences and walkways.
  
  More powerful pressure washers, between 2,000 and 5,000 PSI are usually gas-powered units. These heavy-duty models may not be necessary for most house and deck cleaning; an average electric 1,850 PSI pressure washer may well do the job. Of course, using a more powerful washer will lessen the time it takes to complete the job, so it's better to have too much power than too little. It's also true that if the unit is going to be used frequently and for long periods of time, a gas-powered model will offer more long-term reliability, which is why gas-powered models are generally the ones seen in commercial use.
  
  

Considerations

• Should you take on the chore of pressure washing yourself, or leave it to the professionals? While using a pressure washer to clean a fence or patio isn't overly difficult, it is a little time consuming and you have to decide how much your time is worth. If the job takes you half a day to complete and you have to pay for the rental of the pressure washer, you might decide that it's more cost-effective to pay a professional to do it.
  
  Pressure washing the exterior of your entire home is a labor-intensive endeavor that also carries with it a little personal injury risk, especially if you'll be using ladders or scaffolding in order to clean hard-to-reach areas. If you're comfortable with the risk and are intent on doing this chore on a regular basis in the future, then you may find it worthwhile to purchase a pressure washer and consider it a long-term investment in the appearance of your home.
  
  

Warning

• Pressure washers are extremely powerful tools and should always be used with extreme caution, and in compliance with the safety instructions that come with the unit. At some settings, the water pressure around the nozzle can easily remove flesh from a finger, and can send debris like loose paint chips or wood splinters flying at great speed, so wearing safety goggles is important.
  
  Remember too, that while electric pressure washers can be used in contained and poorly ventilated areas, gas-powered models cannot. Their use requires adequate ventilation to avoid potentially deadly carbon monoxide fumes.
  
  

Tips

• When using a pressure washer, it's advisable to start with a low-pressure spray and then increase it as necessary. Starting with too high a setting can deliver water pressure that could easily remove paint or splinter wood.
  
  It's always a good idea to follow the manufacturer's guidelines concerning the recommended detergents to be used with the pressure washer. Even if you don't use their specifically recommended brand, make sure you stay away from using corrosive cleaners like bleach and rust removers. They'll remove the dirt, but over time, any residue left in the washer can damage the seals in the unit.
  
  

Misconceptions

• Because of the high velocity of the water sprayed from the nozzle of a pressure washer, it's often assumed that the water usage is very high. In actual fact, pressure washing uses approximately 80 percent less water than the average garden hose.