The world's most in-depth and scientific reviews of gear

How We Tested Pressure Washers

Monday June 22, 2020

Many product review websites simply gather data from manufacturers or scour user-generated reviews to make a guess as to which models are the best based on research — we go much further than that. We exhaustively research for days or weeks on end, and then we purchase every product at full price to eliminate any possibility of bias. Once we get our hands on the various machines, tools, and devices we go to town putting them to the real world, in-depth test to discover which ones are truly the best, not just supposed to be the best.

To determine which pressure washers are the best we used objective tests, subjective judgment, and our own professional experience to narrow our assessment down to four key metrics with a weighted score according to their importance. Read below for a full explanation of our exhaustive experimental techniques.


Cleaning


Because the main purpose of a pressure washer is to jet filth and debris away from a vehicle, driveway, patio, or other piece of property, the first thing we wanted to consider was each model's cleaning performance. Before we developed any tests, we took the most obvious course of action — we hooked every machine up and started jetting and spraying anything and everything around that needed washing. After cleaning gutters, washing the mud off trucks, and blasting the scum off of exterior walls we had a subjective feel for the difference between the power and settings of each model; we were then confident that we were ready to develop some tests for this metric.

The Simpson has spectacular spraying power. With the right nozzle  washing the exterior of buildings is effortless.
The Simpson has spectacular spraying power. With the right nozzle, washing the exterior of buildings is effortless.

Pressure and flow rate both influence cleaning power, so the eggheads of the pressure washer world have coined a term known as "cleaning units" (CU) that accounts for a combination of these two factors. CU is calculated by simply multiplying gallons per minute of flow (GPM) by pounds per square inch of pressure (PSI).

Here at TechGearLab we often find that manufacturers' claims don't always quite match up with our findings, so we decided to measure CU for each model on our own. To measure PSI, we purchased an inline gauge along with the appropriate fittings to fit the gauge in between the end of each high-pressure hose and its wand.

We used a pressure meter to accurately measure each model's PSI.
We used a pressure meter to accurately measure each model's PSI.

In order to determine an accurate GPM, we broke out the old trusty stopwatch, a water tank, and a scale. We then let each washer rip with their smallest degree included nozzle for a full minute into the tank and weighed the water. Knowing that water weighs 8.34 pounds per gallon, we were then able to calculate GPM, then CU.

To measure flow we dispensed water into a tank for precisely one minute  then weighed it.
To measure flow we dispensed water into a tank for precisely one minute, then weighed it.

The next test we developed was a blend of quantitative and qualitative analysis. Considering that there are so many inconsistencies when spraying fences, driveways, and vehicles we sought out to develop a more repeatable test. We took a rectangular piece of carpet and coated it with a measured amount of activated carbon, then timed how long it took each pressure washer to get the carpet back to what we considered to be a suitable amount of cleanliness. During this test, we also paid close attention to the feel and comfort of the individual tools while operating them.


Next, we built a 12-foot long wooden ramp that we adjusted to an incline of 24 degrees that we dubbed the "testing trough." Along the sides of the trough, we made markings of increments every 0.25 feet. The goal with the trough was to see how far up the incline each pressure washer could sustainably hold a standard bocce ball. This gave us a tangible and observable way in which to add another numeric value to our cleaning metric.


Portability


One of the best things about owning your own pressure washer is that you are able to use them all over your own property, or even at several different locations. When it comes to portability, however, they are not all created equal. The first measurement we took for this metric was each model's weight, although we quickly learned that heaviness is not synonymous with portability. Some of the models that tipped the scale were the most convenient to roll around due to their large tires and wisely placed handles. That being said, those models are also the hardest to get into and out of a vehicle. Conversely, the lighter versions might be convenient to carry around and store, but if you're dealing with rough terrain you might end up carrying them for quite a while, whereas a heavy version might be a breeze to wheel around.


We took each model and tried pushing and pulling them around in a variety of common surfaces to score how well they moved around once they were at their home or job site.


Some types of wheels will easily glide across the driveway, but won't move an inch in the dirt or grass.

It isn't too much work to carry this machine around -- something we were thankful for given its wheels mediocre off-road performance.
It isn't too much work to carry this machine around -- something we were thankful for given its wheels mediocre off-road performance.

Next, we measured the cubic dimensions of each model to accurately determine how much room they're going to take up in your garage, shop, or vehicle.

Noise


When it came to noise, we immediately noticed that the pressure washers we bought showed a huge degree of variance from model to model. Some models emitted nothing more than a mere purr, while others roared throughout the whole block. There are electric versions that only make noise while the trigger is depressed, there are also some that constantly run once you turn them on. Then there are the gasoline-powered models that not only constantly run, but get way louder while they are in use. To test noise we started off by having a panel of judges tell us if there were any models that emitted an especially annoying or bothersome pitch or whine.

Next, we took a sound meter reading from directly next to the machine to measure decibel levels. Finally, we took a second decibel reading from a measured distance of 25 feet away.


Ease of Use


How difficult these tools are to use can be a determining purchasing factor for many people. If you're a gear head, you might not mind a model that requires a manual start involving choke levers, gas cans, and a warm-up period. Another person may just want to plug it in, turn it on, and start washing. To score each model for ease of use we looked at the subtleties that separate each model from the other. First of all, we noted the location of the hose connections and how trying they are to connect or disconnect, their location on the machine, and how likely they are to get tangled.


Next, we looked at the hoses themselves. We measured the length of each hose, then we made a judgment as to how stiff each one is and how difficult they are to store. Some models came with reels or handy hose racks, other models came with hooks, and a few came with nothing more than a velcro strap where the user is expected to figure it out on their own.

The hose on the Simpson is bit difficult to deal with  but once it's rolled up its tidy.
The hose on the Simpson is bit difficult to deal with, but once it's rolled up its tidy.

We then looked at the length and location of the cord for the electric models, and where they are looped up and stored on the machine. Much like the hoses, there are many various ways in which the manufacturers have designed their models stow them.

The RY142300 has plenty of holders to keep your cords and hoses as organized as possible.
The RY142300 has plenty of holders to keep your cords and hoses as organized as possible.

We considered maintenance, which just boiled down to whether the model was gas-powered or electric. Electric models should have zero maintenance. The fossil fuel models, however, will require gas refills, oil changes, and other small engine maintenance.

Gas-powered pressure washers require significantly more maintenance and upkeep than electric models  with the 7132 being no exception.
Gas-powered pressure washers require significantly more maintenance and upkeep than electric models, with the 7132 being no exception.

We also considered the stability of each machine. Some models feel sturdy and stout, others can easily be pulled over if a hose gets kicked or yanked. We then noted the various storage locations for nozzles and any other compartments for attachments around each washer. Finally, we rated and recorded the type of soap container each model had, if any, and how intuitive they are to use.

Conclusion


Testing pressure washers was a blast for us. Our passion is to give you the best information possible so that you have the knowledge and the know-how to make the perfect purchase.