There are so many advantages of a hot water pressure washer over conventional cold water pressure washers. Mainly, it is able to clean a lot more efficiently and faster because it ejects super heated water at very high pressure. For example, if you clean surfaces covered in grease with cold water pressure washer, it will eventually harden the grease and produce a waxy surface that will even be harder to remove. In fact, it will even make the job of cleaning it a lot tougher.
On the other hand, if you use hot water pressure washer, the heated water will soften the grease and even melt the ones that have hardened on the surface. The pressure will simply blast and wash the grease away.