All about pressure washer PSI, GPM and CU
Here we talk about what a PSI rating really means – and the two other standard power washer ratings you should use to compare pressure washer models
PSI (Pound per Square Inch)
rates the force, or power, of the water that the pressure washer pump is able to produce. The pump, powered by an engine, is the part of the washer that pressurizes the water that flows out of the nozzle. And the higher the PSI rating, the more pressure. And more pressure means more cleaning power.
GPM (Gallons per Minute)
is another rating that you should use to compare pressure washer models to help you decide which one to buy. Just like the PSI rating, GPM is a rating that applies to the pump of a unit. GPM measures the rate of the water flow through a pressure washer pump. The faster the water flows through the pump, the faster the dirt can be washed away.
CU (Cleaning Units)
is the rating that you can use to understand the power of combining the PSI and GPM. The CU rating is calculated by multiplying PSI by GPM. So, a power washer with 2,200 PSI and 2 GPM has a 4,400 CU rating.