Pressure Washer Ratings
Choosing a product that is powerful and durable enough to ft your cleaning needs is key. The heavier the duty level, the longer lasting and more powerful the cleaning machine is and the more time you will save.
There are a lot of nasty spots that you can find hard to get rid of. Motor oil stains in the driveway. Slippery mildew on the deck. Carbonized cookout detritus on the grill. All you see ahead is hours of backbreaking labor using plenty of elbow grease.
You just want the mess gone. A pressure washer can efficiently exile the filth in a fraction of the time it takes using a brush and bucket of water. It transforms your humble garden hose into a dirt-demolishing, deep-cleaning machine.
Before you break out the heavy artillery, remember that all pressure washers should be used with care. These tools deliver a concentrated and powerful high-pressure stream of water, capable of causing serious injury and damaging property. For this reason, further explained below, we limited our recommendations to a subset of the many models that we tested.
How Does a Pressure Washer Work?
Pressure washers use an electric motor or gas engine to power a pump, which forces water at high pressure through a concentrating nozzle to quickly discharge away collected filth on surfaces such as decks, patios, and driveways. You can clean sidings, outdoor chairs and other items that are really hard to clean.
The cleaning ability of a pressure washer is excessive, removing dirt, grime and algae efficiently and effectively. Some may consider this item a luxury purchase, but a pressure washer can significantly increase the ability to uphold and clean your property, giving it greater worth. The goal of this buying guide is to help you understand what a pressure washer does and what you need to look for when deciding to purchase one for yourself.
Before we start talking about buying pressure washers we need to define some basic ratings:
- HP (Horse Power): This is how much power the engine can generate. This rating is important because it directly relates to how much pressure the pump can generate.
- PSI (Pounds Per Square Inch): This is how much force is being generated and released by the pump.
- GPM (Gallons Per Minute): This is the rating given to express how much water is being spent and released by the machine.
- CPU (Cleaning Power Units): This is one of the least understood, yet most important rating for pressure washers. To regulate the CPU rating of a pressure washer, you multiply the PSI by the GPM. The greater the CPU the greater the ability the machine has for cleaning deeply and efficiently. Often a consumer is so focused on the PSI of the machine that they do not take the time to look at the CPU. For example, a pressure washer may have 2800 PSI and 2 GPM giving it a CPU of 5600. Another pressure washer has only 2400 PSI but has 3 GPM giving it a CPU of 7200. In this example, the lower PSI machine has more than 20% more cleaning power than the higher PSI rated machine. The result is that the 2400 PSI machine will be able to clean an area 20% faster than the 2800 PSI machine. CPU is sometimes called Cleaning Unit (CU) or Cleaning Power(CP). The CPU rating allows the consumer to associate different machines effectively.
Now consider this, a garden hose will be about 6 GPM and 10 PSI giving it 60 CPU. With a standard spray nozzle attached to the garden hose you can get around 5 GPM at about 40 PSI generating 200 CPU. We all have seen the difference of how much more operative a simple spray nozzle is at cleaning dirt off surfaces. Trying to clean your driveway with your garden hose spray nozzle generating 200 CPU is ineffective. However, if we take a midrange pressure washer a 2 GPM and 2500 PSI (5000 CPU) this is a astounding 25 times increases over a spray nozzle. A commercial pressure washer at 4 GPM and 4000 PSI is an unbelievable 16000 CPU.
It is not difficult to imagine the difference in competence.
Comparison between a Gas Powered and an Electric Pressure Washer
- Gives out more pressured water.
- Can clean large areas like sidings, decks, driveways without the need of chemicals.
- It can easily dispatch tough filth that can’t be removed easily.
- When the nozzle is set on a wider angle, it gives us more pressure.
- Electric models run on a narrow nozzle setting.
- It makes a lot of noise and is very heavy.
- It also requires maintenance a lot.
- If you keep it running without using, you can overheat the pump and ruin the machine, possibly failing the safety valves.
- In a cold weather, the pumps are to be winterized using antifreeze.
- You can’t store the gas machine inside your home either due to safety reasons
- Electric washers are best for outdoor furniture, patios or decks.
- They are good for small jobs that you must take care of.
- They are very lightweight and discrete.
- They don’t require a lot of maintenance and they do not emit any type of smoke.
- They can turn on and off easily.
- They are very easy to store and are easily accessible.
- The water pressure is lower, which means that you are going to have to spend more time in cleaning.
- The nozzles and wands are less sturdy, they have weak plastic material.
- They don’t have metal fittings which are found on the models that are gas powered.
- The area that needs to be cleaned is limited to the unit’s cord and hose’s length.
What is A Pressure Washer Comprised of?
Every pressure washer is made up for four main parts. It is important to understand the components and what they do. Below are mentioned the parts that are found in a Pressure Washer.
This is the part of the pressure washer that receives water from your garden hose, pressurizes the water to thousands of PSI then sends it out. There are several common types of pumps that you will see in commercial and home owner type machines.
The wobble pump is on the low end of quality. The basic design consists of a plate that is offset and then forced to wobble by several pistons pushing against it. There are two or more pistons pushing against a plate at different intervals which makes it the plate “wobble” very quickly, creating pressure. This style is very inefficient (70% due to piston spring resistance on each stroke).
The axial pump is very similar in design, but has a larger oil reservoir and larger bearings. This allows the pump to run cooler and results in longer pump life. The larger cylinders in the axial pump allows it to generate more PSI and GPM than a standard wobble pump. Axial pump performance is an improvement over the wobbles pump, but still suffers from piston spring resistance.
The triplex pump is a piston and plunger design featuring three piston rods that are synchronized together creating a smoother pressurization resulting in more consistent flow that nearly eliminates pulsation. These are often on much higher quality machines.
A triplex pump is much more efficient than an axial-style pump. Triplex pumps also run much cooler and lasts longer. Another benefit of this design is that a Triplex pump generates much less heat and therefore runs cooler than an axial-style pump. Heat is the number one cause of failure in high-pressure pumps. For this reason, an axial pump can easily provide 1,000 hours or more of operation before needing any maintenance, whereas a wobble or axial-style pump typically has a life span of 200-600 hours, after which the pump cannot be repaired economically. When a camshaft pump does require maintenance, the easily accessible pump head, replaceable cartridge-type valves, and ceramic piston sleeves makes repairs quick and easy.
- Drive System
The “drive” describes how the motor is connected to the pump.
Direct drive systems are the most common. Compared to a belt drive system this is a much simpler method needing less parts and space resulting in a more compact design. Direct drive is also considerably more economical than an equivalent rated belt drive machine.
Belt drive systems are typically seen on more industrial platforms. The belt drive turns at a much lower rpm (1725 rpm vs 3450 rpm of a direct drive). The belt absorbs engine vibration which will wear out a pump faster. Since the pump turns at a slower speed all the pistons and valves in the pump will be larger. All this adds up to a cooler running machine that will last considerably longer than an equivalent direct drive version. However, there is slightly more maintenance and considerably more dollars involved (10-30% more). If you are using your pressure washer for industrial applications and expect to work with it almost every day, then this is what you want. However, an equivalent direct drive machine will have the exact same performance for a lot less money.
The three most important factors in choosing a pump: QUALITY, QUALITY, QUALITY.
A lot of the low-cost pressure washers with no-name pumps on them (or pumps on cheaper name brand machines) have very low life expectancies (Some as low 60-100 hours). When buying a pressure washer, make sure you find out the life expectancy of the pump. If the information is unavailable, stay clear because it is very likely that the manufacturer does not want you to know how low it is. Another very important factor to consider is parts availability. Before buying your machine, ask where you can get parts if you need them. After the sales person tells you, verify what he is saying is accurate by contacting the business that was referred.
If you are buying a new machine for $200 or less, expect it to be a disposable machine that might last you one season. To prep your pump for winter flush it with clean water and prime it with anti-freeze. On gas models pull the rope slowly a few times so that the pistons move around to make sure the anti-freeze cycles through the pump.
The engine is the part that powers the pump. The more powerful the engine (rated in HP), the greater the PSI and GPM that can be produced. Engines are either gas or electric power and will typically have a life hour rating on them.
These motors are very low maintenance and quiet. There is also no exhaust so they can be used indoors or poorly ventilated areas. Your typical electric pressure washer that is 110 V and 15 A will be light duty because the engine is not strong enough to generate much PSI or GPM.
Generate much more power and are a lot more mobile because they do not need to plug into an electric power source. Since gas engines are more powerful the pump can generate considerably more PSI and GPM so that they can clean faster and deeper than any 110 V electric pressure washer could. However, they do take a little more maintenance and cost more to operate. They must be used in well ventilated areas because of carbon-monoxide fumes. All 4-cycle engines operate on regular unleaded gasoline. It is strongly recommended to use fuel stabilizer if you do not use your machine often (or are winterizing it). Gasoline begins to break down in a month and can start clogging up carburetors and fuel lines. Avoid this with some fuel stabilizer in the tank and in the jerry, can you store your fuel in.
When it comes right down to it, the two most important things to ask about the engine is how much horsepower it has and how many hours it is rated for. The better quality the engine, the longer it will last. However, quality does not necessarily translate into more power. You can have some excellent quality engines that can last you a very long time, but they were built to generate low power.
Accessories That Come with The Washer
There are some accessories that come along with the washer. Without these, your pressure washer is useless. It would be like having a drill without any drill bits. They are mentioned below.
- Pressure Washer Hose: Everything starts with the pressure washer hose. You will usually want 50 foot lengths as most people tend to find 25 feet to be a too short for a lot of applications. Make sure you get a quality hose with the proper PSI rating to match your machine. A poor-quality hose will breakdown faster, is more susceptible to leaks and kinks and will usually be less flexible and harder to work with.
- The Wand: is the most common accessory and every pressure washer should come with one. You can change the spray pattern with the different tips at the end depending on the application. From very narrow spray to generate higher pressure at the tip for deeper cleaning to a wider spray that has less pressure but covers more area. Almost all pressure washers include a hose and wand.
There are other attachments that include:
- Dirt Blaster: This is a nozzle that goes on to the end of your wand. It has a very narrow spray that spins in a circular motion very rapidly. This attachment is great because it can quickly clean hard surfaces very well and when used properly avoid the ‘tiger stripping’ effect on your driveway that happens with conventional spray tips. I would avoid using this on soft materiel like wood because it will damage it quickly.
- Extension/Telescoping wands: A wand that’s adjustable up to 18′ or 24′ in some cases for cleaning out of reach areas. This is a great benefit if you need to reach up high so that you can avoid trying to pressure wash while standing on a ladder.
- Gutter cleaners: This is a simple hooked piece that goes on the end of your wand. It lets you get into your gutters to clean them out. Be careful though with high pressure machines, if your jamb them into your gutters carelessly the pressure can strip out the caulking in your gutter joints (especially in the corners). If this happens your gutters will leak and will be an unpleasant repair experience.
Whirl-a-Ways: These are a great addition also. They are a surface cleaning attachment with two rotating nozzles inside. The range is in diameter from 12” to over 36”. These greatly speed up cleaning of any large flat area.
- Ball Valve: This is one of my personal favorite items. It is a shut off lever that you put at the end of your hose. So, if you want to switch attachments you can turn off the water pressure/supply without having to walk back to your compressor and turning it off.
Hot Water Pressure Washers
Hot Water Pressure washers are commercial Pressure Washers with a built-in water heaters. The cleaning power of the machines is considerably more than a non-heated machine with comparable PSI and GPM because hot water simply cleans more effectively than cold water. It breaks down and removes dirt and grime faster than a normal pressure washer can, reducing the amount of time you need to spend cleaning. These also clean heavier stains (like grease) than non-heated pressure washers.
Do not feed hot water into a normal pressure water pump that was not designed for it. The heat will damage seals and O-rings.
What Makes It Better?
Detergents can greatly increase the speed of cleaning and help remove tough stains. Most pressure washers come equipped with a venture tube that will draw in the detergent from a bottle or pale and add it to the water stream. The detergent should be first applied with a low-pressure spray, given some time to do its work to break down the dirt then rinsed off with a normal high-pressure spray.
It is strongly recommended to use only pressure washer specific detergents. Using wrong detergents can clog your system and potentially damage your pressure washer. Also, be aware of the chemicals you are spraying to make sure they are environmentally safe. Special permits may be needed for certain heavy duty industrial chemicals.
The Final Verdict
When it comes right down to it, you need to buy a pressure washer that fits your application. There are many different types of pressure washers from very low end electric machines to extremely powerful industrial machines. Before you buy a machine, you need to sit down and determine what you plan to use it for. One of the most important questions like ‘How much will I be using a pressure washer?’ If you are a homeowner you will probably use it two or three days per year putting 20 hours’ work on your machine per year. In this case getting a machine rated for 500 hours will last you (if properly maintained) 25 years. However, if you are working with it a part of your business you will want something rated for 2000 hours or more.
Also, you need to determine what applications you will be expecting the pressure washer to perform. If you are looking at doing light occasional chores, such as cleaning smaller areas, cars, lawn equipment, dirt, algae then you would want around 4500 CPU. If you are expecting to do more frequent work and bigger jobs such house siding, large areas of concrete, farm equipment then you would want a machine than can produce 12,000 – 16,000 CPU. Commercial and contractors will want something rated around 25,000 CPU to do the extremely demanding jobs and heavy-duty jobs and to speed up the cleaning process with the extra power.
Finally, plan in advance what attachments you will want in the future and make sure that the pressure washer you buy has enough power to support them.