While the vast majority of the calls we receive are for pressure washing or power washing, whether that be a home, office, driveway or roof, most people don’t realize they are actually two separate services. The differences in the services are based on temperature and equipment, that’s right, temperature and equipment. A power washer is just a pressure washing with a heating unit or “hot box” connected to the outlet. Water pumps out of the pressure washer into a heating unit and finally out of the hose at a temperature upwards of 300F, which is more helpful to the technician for removing gum or anything oil based, whereas a pressure washer or “cold water unit” would have a little more difficulty and would require some form of degreaser to achieve similar results. Both units have the same psi ratings and most people don’t really understand that there is a difference and use both terms interchangeably. So let’s say you were wanting to get your businesses drive through or dumpster pad cleaned, your best course of action would be to choose a company with a power washer or “hot water unit” because they would use less chemicals and less pressure and stress on the surfaces being cleaned. There is another possible advantage to a power washer and that would be in colder climates theoretically the chemical used to clean homes and driveways the majority of the time, sodium hypochlorite, works a little better at warmer temperatures again cutting down on the amount of chemical needed to do the job.
Now that we have discussed the more popular terms let’s talk about Soft Washing. A soft wash system can be run by several different types of pumps with the most common being a 12 volt. On these systems you can control the percentage of surfactant or “soap” and sodium hypochlorite a little better and ,since every substrate has a different recommended percentage based on its porous nature and amount of organic growth, may be a more effective method of application. The normal psi for most soft wash systems range from 60-120 psi which is comparable to a normal garden hose. The pressure washing systems can achieve similar results by using one of two added pieces of equipment, the downstream injector or an x-jet. A down stream injector pulls chemical into the hose as soon as it exits the pump combining it with water and a surfactant or soap to make it “stick” to the surface. This coupled with a larger orifice tip or “soft wash tip” on the end of the gun is a very effective application method but is limited to the substrates that it can be used on because it can’t achieve a high ratio of sodium hypochlorite. The x-jet is also used with pressure washers and is the same idea but the chemical is pulled from the gun rather than beginning of the hose giving possibility for a higher concentration of sodium hypochlorite. Both of these applications use what is known as the Venturi Principle which states when water flows through a restricted area, it velocity increases and pressure decreases. The larger orifice on the gun allows the velocity to decrease which allows the pressure to increase opening the valves in both pieces of equipment allowing chemicals to enter. Let’s give another real world example. If you had black stripes or moss growing on your shingle roof the proper method would be to use a soft wash application because the concentration of sodium hypochlorite for roof shingles is pretty high, around the 4-5% range, the downstream injector cannot accomplish this task and an x-jet wouldn’t have the precision because of the amount of overspray.
Each application method has its own place and are in some cases interchangeable. What we explain to all of not only our customers but potential customers as well is that if a company comes out to spray high pressure on your home or business, especially the roofs that you should stop them immediately. Our method and our beliefs which are backed by the roofers association of America, is that a soft wash method is best for almost any situation. So whether they are soft washing using a pressure washer, power washer or a soft wash system the results can be the similar other than for roof applications, which require a soft wash system to reach correct ratio and minimize overspray. All of the applications can be done with low pressure which will prevent damage to the substrate, so keep in mind, you want to clean your home or business but do so without damaging or reducing the lifetime of it.
