There is so many different brands of pressure washers out on the market today, that it is so hard to find the correct one for your cleaning application. You do unfortunately need to be mindful of where you get the pressure washer from, who makes it and is what it says it does it actually does. Unfortunately sometimes what is advertised of a pressure washer isn't exactly what the pressure washer does.
For example: - I have had a few clients call up with relation to what sort of pressure does a pressure washer do once you add a turbo or rotary nozzle to the machine. A turbo / rotary nozzle doesn't increase the pressure of the machine but it does increase the cleaning efficiency of effectiveness of the machine by 30%, so if you have a pressure washer that does normally 3000psi and you add a turbo / rotary nozzle to the lance the cleaning efficiency or effectiveness will be 30% more making it clean like you are using a 3900psi. I have noticed some companies advertise that the turbo / rotary nozzle increase the cleaning effectiveness by 60% but unfortunately this is not correct. It would be nice if it was true but its not.
Another common question or machine that I come across is the pressure that a pressure cleaner does. We have had pressure washers come into our workshop that have a 6.5HP engine on it and it stats on the pressure washer that it produces 4200psi at 15 litres per minute. This again unfortunately isn't correct. A 6.5HP direct drive pressure washer can't product 4200psi @ 15 litres per minute. The most 6.5HP pressure washer will produce being a direct drive unit is say 3000psi @ 11 litres per minute, so please be mindful of what you are purchasing to ensure you are getting what is being advertised and what you are paying for.
Just as an ending note, a lot of people have said to me that they need more pressure than water flow for their cleaning and yes pressure does help, but it is also the water flow behind the pressure that increases the cleaning efficiency and effectiveness, so it a combination of the two that will get the cleaning done.
Click below to see a detailed grid that will help you to choose the right pressure washer.