What's more important, PSI or GPM?
It's actually the combination of the two (units of power) that determine the size of machine you should get. The measurement units of cleaning power is an easy way to rate pressure washers. To determine the units of cleaning power for a machine, multiply the PSI by the GPM (PSI x GPM). This calculation helps you compare different washers, to determine which one is most powerful. The higher the number, the more powerful the pressure washer.
For example, let's say you are considering one washer with 2 GPM and 3000 PSI and another washer with 4 GPM and 2000 PSI. Which is better? The units of cleaning power on the first washer are 6,000, while the second unit has 8,000 cleaning units. The second machine is more powerful and will likely be the best choice for your needs.
Units of Cleaning Power
GPM PSI Units of Cleaning Power
2.0 1600 3,200
3.0 1100 3,300
3.0 2000 6,000
4.0 1800 7,200
4.0 3000 12,000
4.8 1800 8,640
5.0 3000 15,000