Pressure Washers Buying 2020

Pressure Washers

<a href=

Karcher? Generac? AR North America? Simpson? or a Sun Joe pressure washer? Electric or gas? Low or high PSI? Low or high GPM? Not sure which pressure washer to buy?

There are so many pressure washers on the market today it can drive you crazy trying to select the right one. Relax. This site has all the information you need to make a good choice – without the need to become an expert yourself.

Ever wonder what all those rating acronyms mean, like PSI and GPM? Covered. Ever try to puzzle out which is better: an electric or gas-powered model? Done. Ever ask yourself what kinds of accessories are available from which manufacturers? Done.

You get clear explanations of all those acronyms, specs, and more that help you arrive at a final choice. In the reviews, you get detailed, easy-to-follow answers and to questions, you, sometimes, didn’t even think to ask. I rank for you the more popular models – by PSI, GPM and other useful attributes – and explain why they’re popular.

What you’ll find here isn’t just a lot of technical, gear-head jargon that assumes you’re an expert already. If you were, you wouldn’t need this site for guidance. Instead, you get practical, easy-to-digest info and advice that helps you make the right buying decision.

I do that in as unbiased a way as humanly possible. I have no favorite manufacturer and no financial interest in helping one over the other. I have preferred models, certainly, and ones I’m not as keen on. But those preferences are the result of long study and observation of pressure washers in real-world use.

Strangely enough, I also have a passion for the subject. I love good products and I love to tell others about them. Nothing gets me quite as excited as discovering a new product that does the job better, easier, and – one always hopes – less expensively than some older one.

I take the long-term view here. Pressure washers cost more than many other home care products. You want and expect to use one for a long time and want it to continue to work well for years. So, I look beyond the flash and consider how your model might work over the long haul, how it stands up to the years of hard duty you’ll give it.

So, join us in exploring the world of pressure washers. Look through some of the articles that explain the basics. Read some reviews. And, by all means, let me know what you think. Like the manufacturers, I’m always looking to improve how I can provide you with all the info you need. Thanks, and Welcome to

What is PSI? What is GPM? How Much Pressure do I Need in a Pressure Washer?

Investigate pressure washers and you’ll quickly find yourself encountering acronyms like PSI, GPM, CP, HP, and more. It’s easy to spell out what the letters stand for – pounds per square inch, gallons per minute, cleansing power, horsepower, etc. But what do they mean in practice? What do you need to know about them to evaluate which pressure washer is best for you? Fortunately, you don’t need a degree in engineering to understand the answers to those questions.

PSI – Pounds Per Square Inch

Despite their many similarities pressure washers differ, unsurprisingly, in one key area: the pressure they provide. Engine size, hose length, nozzle options, and more contribute to their overall value but the ‘oomph’ is the main thing. The pressure is ranked in PSI (pounds per square inch) in English units or NPM (newtons per square meter, also known as pascals or bar). We’ll stick with the English units since they’re more familiar to most readers and the manufacturers more often rate their products this way.

A pound is technically a simple measure of weight – typically the amount a given mass ‘pushes’ under the influence of gravity. That’s what your bathroom scale measures. But more generally, it’s just a measure of a force. When that force – water pushing through a hose, in this case – acts on or through a certain area it’s possible to form a new unit: pressure, the force per unit area. That’s the technical definition of pressure, how hard something is pushing against a big a flat space.

Think of it this way… Imagine pushing on your hand with the back of a wooden pencil that has no eraser. If you push with only moderate force you can feel it but it doesn’t hurt. Now use the same amount of force but use the other, sharp, end of the pencil. You may puncture the skin. That’s how a smaller area can produce higher pressure with the same amount of force. It’s essentially the reason that hose nozzle diameters are so small.

For those interested in the technical explanation… In mathematical terms, the reason for all this is clear. P = F / A implies that making the denominator (area) smaller will increase the total (pressure) just the way making the numerator (force) larger would. Physically, this is exactly what happens. Push with more force or make the area smaller and you increase the total pressure.

So, how does all this relate to which pressure washer is better for you?

Well, not surprisingly, greater pressure provides both more cleansing power and lets you reach higher heights with the stream. A gas-powered, 3,000 PSI pressure washer will, all other things being equal, let you get up to those high eaves on a two-story house. The electric model that provides, say, only 1,500 PSI may not reach.

How Much Pressure is Enough?

Also not surprisingly, there’s no unique answer to this question. It depends on what you need to clean, how durable the material is, how you use the pressure washer and other variables. Even a relatively modest-strength pressure washer – say 2,500 PSI — could put a hole in softwood if you move the nozzle close enough. To give you some rough guidelines for real-world use, consider what you plan to wash with your pressure washer most often.

A low-end electric model that generates 1,500-2,000 PSI can be useful for cleaning wood fences, patio furniture, the car, and other relatively easy cleaning jobs. On the other hand, you might require a high-powered gasoline model – one that can deliver, say 3,100 PSI – for the tougher scenarios. Such things as cleaning oil slicks off the garage floor, blasting accumulated mud from rain gutters on the second story, and the like often require substantial pressure.

GPM – Gallons Per Minute

Similar considerations apply to selecting a pressure washer based on flow rate, typically measured in GPM (gallons per minute) or LPM (liters per minute). The rating is pretty much what it sounds like, a measure of how much water can flow through the hose per unit time. For the same pressure, more water generally means more cleansing power.

Imagine that the water just kind of dribbled out rather than spritzing out at high pressure. You might at first think it wouldn’t clean much. Yet, even if you just gently pour water out of a big bucket onto the patio it does tend to wash away a fair amount of mud. Now imagine ten such buckets or 20 or 100. The more water, the more fluid there is to carry away crud.

Not only that, but the flow rate also affects how large an area you can clean in a given amount of time. A lot of water produced in a short time lets you hose down a big deck more quickly. A small amount in the same time – that is a smaller flow rate – means you have to swish the wand back and forth longer to get the whole deck clean.

Naturally, that total time is influenced by the pressure, nozzle shape, and other factors, but on average a higher flow rate will do the job quicker. Something in the lower range – 1.5 GPM for example – might clean a 40 square foot patio in 10 minutes. But to clear off a 150 square foot patio in the same time would likely require a flow rate closer to 3 GPM.

Notice that the area has almost quadrupled but the flow rate is only double. That’s just the way these things work. You often get much more ‘bang for the buck’ from a higher rated pressure washer. But keep in mind that those higher flow-rate machines typically have much higher pressure ratings as well. The two tend to be ‘coupled’ by the manufacturers.

Turning that around, as with pressure ratings, lower-end pressure washers typically offer lower flow rates. An inexpensive electric model might produce only 1.5 GPM; a beefy gasoline-powered unit might push 2.7 GPM or more. Naturally, as with higher pressure rate washers, the price tends to go up as the flow rate does.

CP – Cleansing Power

Many pressure washer manufacturers offer a number they call Cleansing Power, sometimes called Cleaning Units (CU). It’s simply the pressure x flow rate, PSI x GPM. In my experience, it’s not terribly useful. It can make one model look more impressive than another, but usually, it simply makes a relatively weak pressure unit look better by offering a larger flow rate. That’s not usually a good tradeoff.

Horsepower (HP) and Wattage (W)

This category is less important when selecting pressure washers but I’ll cover it for the sake of completeness. It will come as no surprise that more horsepower usually means a higher pressure rating. But not always; that’s one reason for discussing it. If a gas engine generates a ton of power but the washer offers only a modest PSI you know that unit isn’t very efficient. Something to watch for.

Similar considerations apply to electric models. Here, the tricky bit is that manufacturers tend to tell you how much current the pressure washer’s motor draws – in amps – rather than how much power the motor actually provides to the pump. Such is life. You can still get a rough idea by comparing the relative current ratings – say 13A versus 15A – of different models.

In general, whether considering a gas-powered model or an electric version, more power is better. But, of course, you have to balance that against other factors. Cost is the obvious one but, particularly in the gasoline-powered arena, the noise level is another. More powerful engines are usually noisier. They may also run up against legal constraints, such as the need to be CARB compliant in California, for example.


It’s a good idea to understand what the various pressure washer ratings mean. Getting a technical understanding helps you evaluate the likely real-world behavior of one model versus another. And, since the various models invariably cost more for higher numbers you can get a good idea this way whether the larger price is justified.

Leave a Reply