When I had a holiday job in a bacon packing factory, at the end of my shift I had to pressure wash down the slicing machine. It wasn’t a great job but it paid well and by the end of it, I had hand muscles like Arnie- weilding a pressure washer for 30 minutes a day was hard work. But I never actually considered the domestic use of one for decades afterwards.
I think that generally the whole concept of a pressure washer is one that’s a bit misunderstood. The fact that the water comes out under high enough pressure to score the moss and grim off of a patio, or take the welded on bird mess off of car or house windows, sort of leads to the almost unconscious rationalisation that they use MUCH more water than a normal hose would. Our mains pressure is good but the hose we have for watering the garden and filling up the paddling pool on the one warm day we have every summer, only really manages a firm dribble. Our pressure washer though can hit a small child from over 30ft (no children were harmed in the testing of this claim- honest). It’s not that it uses more water, it doesn’t and can’t because it can only take the water that’s supplied at mains pressure, but what it can do is pump that water through a much much narrower nozzle so the water comes out a lot faster. Same amount of water, much smaller hole. Matron.
We have a fairly compact Karcher K4 pressure washer, but there are a bewilderingly different array to choose from. To this end Tesco have kindly written a Buyers Guide to Pressure Washers, which goes in to all the technical details of what is suitable for which situation. As the name suggests, pressure washers wash under pressure but the pressure can vary from machine to machine and some tasks are more suited to one than another, so it’s worth a read if you’re considering getting one.
Ours has got just about enough oomph that it does a pretty good job with the jet foam nozzle contraption that attaches to it for car cleaning, so I can personally vouch for the benefit of doing a bit of research first. Having said that, without the nozzle on, it can shift any of that bird mess that might have dried on without even really trying.