These two terms are often used to describe a type of pressure cleaning, and many get confused as to what the differences are between the two names. The two terms basically refer to the same thing.
The only minor difference that you might find between a power washing and a pressure washing is that the jet wash in a power washing machine uses hot water while the jet wash in a pressure washer is not heated at all.
Outside of this small difference, the machines are identical. They can both be used to clean large surfaces, removing such things as dirt, dust, mud, grime, stains, salt, mold and chewing gum. They can be used on the exterior of buildings, sidewalks, stairways, patios, driveways, stadiums, parking garages, cinemas, and in the cleaning of cars. They can effectively clean all of this and much more.