A basic look at the variables of pressure washing - The easiest way to start to learn how to power wash is to first understand how various pressure washing systems work. There are four basic elements of the process regardless of what machine or method is used. They are: pressure, water flow rate, cleaning solution, and heat. If we take out just one of these four elements, the cleaning characteristics will change. For example, if you only use a cold water pressure washer instead of a hot water washer, you may have to compensate for that loss by using added pressure, more water flow, or the use of chemicals, all depending on the dirt to be removed, and surface to be cleaned. You will always have to make adjustments combining these four elements in order to achieve the ideal cleaning atmosphere for your particular job. Nevertheless, when learning how power washing systems work, and how to power wash, keep in mind that detergents emulsify the dirt better and faster as the temperature increases. This is especially true when cleaning oil and grease from a concrete surface. That's why hot water power washing systems are perfect for such jobs. Other times, just using high pressure cold water, or hot water will do the trick. And for certain surfaces, and stains to be removed, a "low pressure" wash may be the best choice. Like for doing roofs, gutters, or siding. Or in situations when you mainly just want to let "the chemical" do the work, and then rinse the surface clean afterwards. Always be mindful of the effects of using pressure on the varying materials to be cleaned, and to always take steps to make sure any surrounding vegetation is adequately protected, depending on the cleaning method and solution used.