There are some applications that need hot water for their application and some that require cold. So how do you know which one your job requires? If your job requires cleaning, more than likely you need a hot water pressure washer. Hot water, in general, cleans and disinfects mush better than cold every will, and a pressure washer is no different. With all other things being equal, you will always want a hot water pressure washer over a cold one when looking at a straight cleaning job. So when would you need a cold water unit?
If there is no cleaning involved, you will not need a hot water pressure washer. In fact, a majority of the applications for a pressure washer will need do perfectly fine with a cold water washer. Because, on average, hot water pressure washers cost almost three times as much as cold ones between fuel and purchase costs, you will most certainly want to use a cold water washer whenever you can.
So when, then, is a hot pressure washer absolutely necessary? A good example is cleaning greasy manufacturing equipment. There are many food processing plants that process fatty foods and will not work under cold water circumstances. If you did decide to use cold water, the fatty grease would harden into permanently lodged waxy clumps, which will greatly lengthen your cleaning time. Had you decided to use a hot washer, your grease would quickly break down and wash right away.
So any job that will involve grease, fat, or oils, will need a unit that will preheat the water before it is pressurized. Additionally, there are units that emit high pressure steam, and may be a better suit for your job. These units do not need detergents, cleaning agents, or any other harsh chemicals to operate efficiently and there are many models and types of pressure washers that can accomplish this task. The only way to be sure that you have the right model for your job is to compare the specifications for the unit to the job at hand and make the best choice possible.