Pressure washers can be categorized in several different ways: electric, gas-powered, residential or commercial. There is also another classification, and that’s cold or hot water pressure washers. Apart from the temperature of water they use, they differ in several other areas as well. Of course they both have their pros and cons, and knowing more about each will help you make a better decision. Let’s check how they stack up against one another.
Cold Water Pressure Washers
Except for one diesel/electric hybrid pressure washer all of the units I have reviewed on my website are cold water units. There are plenty of reasons why they are so popular, but the most important reason is probably that, when compared to their hot water counterparts, they are much cheaper and simpler in their construction (especially electric models).
Also, cold water pressure washers are a lot more practical due to their smaller dimensions which make them easier to move around. As far as maintenance goes even gas-powered pressure washers are a lot easier to maintain than the equivalent hot water designs.
Cold water pressure washers rely on the mechanical force of a pressurized water jet to dislodge dirt from the surface that needs to be cleaned. This force is usually enough to break down most impurities, but they are less efficient when it comes to tackling oily or greasy stains that can be found on hard surfaces such as garage floors, pavements and driveways. The use of detergents helps out a bit on some of the less tough stains, but oil and grease are often too much to handle for most cold pressure washers.
Cold water power washers rely on high-pressure water jets to remove dirt, and the higher the PSI and GPM number, the more powerful the pressure washer is. Hot water pressure washers lose when it comes to the sheer amount of pressure, but they have other strengths. Let’s check them out.
Hot Water Pressure Washers
The best analogy I can come up with to explain the effectiveness of hot water units is washing the dishes. That’s right. Think about it. When you are washing greasy plates you are going to use hot water along with some detergent because it is far more effective than cleaning with cold water. It’s the same when it comes to pressure washers.
Yes, but why is hot water more effective? Hold on to your seats because I am going to try and explain some scientific stuff.
For starters we need to look at stuff from a molecular point of view. Water molecules break free from their bonds when heated up to over 200F, that’s how you get steam. It is basically the same with grease and oil molecules. As temperatures rise, their energy levels increase and they can break free from the surfaces they are embedded in. Of course, hot water power washers also use the mechanical force of pressurized water to expel oil and grease particles from the surface. Finally, using soap breaks down the bonds created by grease and oil at a molecular level.
As said, hot water pressure washers have the ability to produce steam which comes in really handy if you want to get surfaces spotless to the point where they’re germ free. However, a hot water and high pressure combo is more effective than just steam. You may also notice that hot water pressure washers have a lower PSI than gas-powered pressure washers.
As far as the cons for hot water pressure washers go? They are big, bulky and thanks to their complex design, more complicated to maintain. They are also more expensive.
So which one to go with? It’s easy. If you don’t have any oil or grease stains to clean save your money and buy a cold water unit. Only if you are dealing with greasy stains often, invest in a hot water pressure washer.