I tried a couple of those electric pressure washers. They just did not have the power I needed to get the job done. One model I had for a little while did not really have any more pressure than using the nozzle on the garden hose without any machine. I looked into getting a petrol pressure washer. One that is powered by a small engine that runs on fuel. You can get them in small units or really big ones that are more for commercial use. I got one that has a lot of pressure behind it. I can dial the force up and down to adjust for cleaning our concrete sidewalks and driveway or our wooden deck surfaces. I can even spray the siding, gutters and windows. The important thing is to adjust the pressure and the distance of the nozzle to the surface. Then use the right nozzle tip too. You do not have to use the super narrow one for every project.
I see my neighbors ruining wood surfaces and even stripping the paint off of metal with the inappropriate use of pressure washers. You should at least read a how-to book and pay attention to the owner’s manual that comes with your machine. Too much pressure can destroy a piece of wood, break a window or cause other damage. On the other hand, if you use them the right way, a pressure washer is a handy tool for cleaning most of your outdoor surfaces quickly and thoroughly. We live in an area where particulates from a nearby roadway that see heavy traffic deposits a lot of grime on our flat surfaces. Our sidewalk is years old and looks new. Not so much for neighbors who do not have a petrol pressure washer. They try to clean theirs, but their methods just do not have the power of a pressure washer that is powered by a fuel-burning engine.