Power washer is a general term, covering a wide range of different types of machine. If you are considering the purchase of a power washer, there are a few pieces of information that will help you to determine the most appropriate pressure washer and accessories for your needs. Get through the following glossary:

• Pounds per Square Inch (PSI) refers to the amount of water pressure, the unit creates. The higher the PSI, the faster the dirt will be loosened from the surface being cleaned.
• Gallons Per Minute (GPM) refers to the volume of water flow directed at the surface being cleaned. A great combination of PSI and GPM should be used to deliver cleaning power. High pressure with little water flow is not effective.
• Cleaning Power Units (CPU) is the best indicator of performance and is calculated by multiplying the max PSI rating by the GPM flow. A power washer with a higher CPU will clean more efficiently.
• Ground Fault Interrupter (GFI or GFCI) is a safety device on electric appliances that are typically used near water that protects against electrocution.
• Water Pumps (plunger or axial) pressurize the water. Plungers can be repaired and last longer than axial pumps. Plunger pumps with ceramic or ceramic-coated stainless steel plungers will last the longest.
• Nozzle is the restriction at the end of the wand creating pressure. Each has different spray patterns affecting the width and strength of the spray. Spray angles of 40 degrees or more are for general washing, 15 to 25 degrees can strip and wash large areas quickly, and a zero-degree (pencil jet) nozzle is great for shooting up high to knock down a bee’s nest or rinse the upper areas of your home but can easily damage soft surfaces, especially wood.
• Horse Power is used to measure the performance of gasoline engines and electric motors. More HP means more power.