Soft washing is the combination of water, chemicals, and surfactants that are applied to substrates at low-pressure
Low pressure allows you to safely place your hand right in front of the 
spray tip and not damage the skin. (WARNING DO NOT TRY THIS AT HOME. If you are using the wrong tip you could severely injure yourself.) Soft washing (low pressure cleaning with chemicals) is preferred for cleaning home or business exteriors. It’s safer than blasting with high pressure and provides a superior quality job. Soft washing can also remove any tiger stripes and/or swirl marks left behind by the home owner or your last inexperienced pressure washing contractor.
Pressure washing is utilizing a low volume of water at high pressure in order to clean
There is a time and place to use high pressure. Such instances are cleaning unfinished concrete, unpainted block or your street curbs. Even then soft washing chemicals will be applied to remove mold your pressure washer leaves behind. If you have used a surface cleaner then you have most likely seen the swirl marks they leave behind. These marks are created by using the wrong tips or by walking too fast when cleaning. Most DIY’ers end up disconnecting the surface cleaner only to use the wand to finish the job and often times still leave those unsightly tiger stripes.
Power washing is the use of high pressure HOT water to clean
Hot water pressure washing “helps” to remove oil stains on your concrete. There are a myriad of different commercial grade degreasers on the market that claim to remove oil stains yet when applied at home they seldom work. Cold water pressure washing combined with degreasers alone is not enough to completely remove a set in oil stain, you will need hot water. There are plenty of pressure washing companies that actually have the words “Power Washing” in their company name yet they do not have the equipment to generate hot water. I get it “power washing” sounds like you are working harder, but 99% of the time most of us are simply pressure washing. I agree that hot water power washing will effectively and quickly remove chewing gum, but unless you are frequently cleaning high traffic shopping centers, there is no need for a power washing unit.