On industrial machines it is normal to use a slower revving motor with a larger pump which means it can be used for longer periods without overheating. Pressure washers can be powered in various ways and each has its advantages. Electric power is the most common source with smaller motors using a 240 volt single phase supply from a conventional plug socket and larger commercial machines using a 3 phase 420 volt supply.
It is a common mistake to view a washer with a high pressure rating as being a better option. A pressure washer should be selected based on what it is expected to clean and not on its pressure rating alone. Whilst using cold water under pressure is adequate for most cleaning jobs hot water does give extra cleaning power for stubborn dirt like grease and grime. Some cold water washers can be used with hot water perhaps supplied by a separate heater for added cleaning power. The maximum inlet temperature indicates the level of hot water the machine can take.
To reduce uncertainty ascertain how long the washer would be used each week and how hard it would have to work. To have a washer working at full tilt all the time will not improve its longevity. It is also important to think about the kind of cleaning required is the dirt caked on? Do you want to clean large floor areas or smaller pieces of equipment. Do you need a hot or cold water version?