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We blasted away dirt, grime, and mildew to help find the right model for you. Ram Jet Pump
Spring is great. Outdoor and yard projects kick back into high gear as the weather turns warmer, but so does dirt, mildew, and mold. All this nastiness seems to collect on any outdoor surface from your house's siding and outdoor furnishings to sidewalks and driveways. To keep the fun as you get ready for summer and make short work of dirty surfaces, turn to a pressure washer. They not only clean with the mechanical action of high-pressure water, they also scrub with the chemical action supplied from cleaners in the machines' onboard tanks (some machines siphon cleaner out of a nearby bucket). Bonus: these machines use less water per square foot to clean than spraying with a garden hose.
We tested more than a dozen pressure washers, some powered by gasoline engines and others powered by electric motors. Our goal was to find out which are the kings of clean and, of those we tested, we list only the handful of the top performers below. Read our pressure washer background below, then the reviews, and keep scrolling to look at some recent machines that we haven't tested (yet) but that we will be moving through our test cycle in the weeks ahead.
The pump that provides the high-velocity jet of water out of a pressure washer may be driven by a gas engine or an electric motor. One is not necessarily better than the other, but which you buy will depend on your cleaning needs, budget, and how you feel about maintaining the equipment you own.
These are best suited for brief cleaning sessions, running from 15 to 30 minutes. They have enough power for general washing of outdoor surfaces. They work well on wood and synthetic decks that need only gentle cleaning, all types of outdoor furniture, single-floor ranch houses, all types of exterior siding, and will clean the undercarriage of a pickup truck. They’re not well suited to heavy-duty cleaning or long sessions in the height of the summer. Their motor, cord, and ground-fault circuit interrupter (GFCI) can get extremely hot. These are much quieter than gas-engine pressure washers, and they need hardly any maintenance. As a bonus, they’re easy to store indoors during the winter.
These are best suited to heavy-duty cleaning. The power afforded by a gas engine can drive a large and powerful pump, enabling these machines to shoot water to higher surfaces, clean heavier deposits of mold and dirt, and even slice thick deposits of mud from equipment such as farm machinery, trucks, and off-road vehicles. A gas engine is much louder than an electric motor, plus requires maintenance in the form of oil changes, replacement air filters, and a yearly check or change of the spark plug. Not to mention you have to be careful about fuel degradation. Today’s alcohol-containing gasoline quickly degrades and can damage fuel-system parts like carburetors and gas lines. Also, gas engine pressure washers are best stored over the winter in the garage or an outbuilding.
All the machines we tested were safe to use, and we encountered nothing in them that caused us any concern. However, pressure washers by their nature demand careful and deliberate handling, both for your sake and that of whatever you’re cleaning.
Both electric and gas pressure washers can damage surfaces. Of the two, the risk is higher with gas-engine machines owing to the fact that they’re generally more powerful. There are some key things you need to know to clean safely and effectively.
Testing pressure washers is the proverbial dirty job. We wash concrete and brick pavements, vinyl and cement board siding, aluminum trim and gutters, faux stone, vertical brick, and wood trim. Vinyl fences and outdoor furniture, too. We even very carefully washed some cars (using the white nozzle). One of the toughest tests was blasting clean three large commercial trash cans with bottoms awash in a nauseating soup of summer stink. They looked and smelled like new cans when we were done with them. Aside from cleaning ability, we look at ease of use. Would the washer tip over if you tugged on its hose? Just how easy is it to get the thing up a set of ramps and into the back of a pickup truck? Was the hose easy to tighten onto the pump fitting? And just how stiff is the hose that takes the water from the pump to the gun? Read on for our evaluations.
Water enters the pressure washer via a garden hose (a) and moves through a pump, which consists of a series of two or three plungers (b) arranged in a line or a circle. The plungers are powered by an output shaft on the engine or from a motor. Each plunger boosts the water pressure sequentially, one feeding higher pressure water to the plunger next in line. The last pulse of high-pressure water exits the pump. The water moves through a component called the unloader (c). This component unloads water if it gets too hot because the gun’s trigger is off. Next, the water travels down the hose to the gun (d). When you pull the gun’s trigger, you send a series of high-pressure pulses of water out the nozzle.
“It’s important to understand that the pump produces cleaning and rinsing efficiencies with high-velocity water pulsations,” says Vince Morabit, a mechanical engineer who’s designed and developed outdoor power equipment from pumps to chainsaws since the early 1960s. “Think of it this way: The kinetic energy in that pulse of water is like a chisel being struck repeatedly by a hammer.”
And since residential pressure washers also dispense cleaner, either out of a built-in tank (e) or by siphoning it out of a bucket, they clean via mechanical and chemical means. You apply the cleaner and then rinse the surface. The cycle is always the same: clean, rinse, repeat.
“The cleaning agent you use is as important as the pressure washer itself,” says Morabit. By selecting the right one, you rely less on the pressure washer’s force and more on the gentle removal of grime by the chemical action of the cleaner.
We tested the power washers below on the exterior siding of a house. Electric models work well on wood and synthetic decks that need only gentle cleaning, plus all types of outdoor furniture.
If ever there was an aptly named piece of outdoor power equipment, the MegaShot is it. For the money, you get a big Honda engine with massive air cooling fins on its head (it’s one of the best engines in the business, by the way) and an equally hefty pump, complete with anodized hose fittings. And the combined action of that engine and pump produce a lot of dirt-blasting capability. No, this isn’t a commercial power washer—you’d need to spend another $1,000 to get there. But it comes about as close as you’re going to get at this price. We used it to blast clean concrete (including removing masonry stain), dirty vinyl siding and trim, mildewed wood, outdoor furniture that could only be described as grotesque, and equally nasty vinyl fencing. While we were at it, we blasted anything else in the vicinity that looked even remotely dirty.
Our verdict: This is a productive, no-nonsense pressure washer complete with a pull rod choke and a big red on/off switch. But, hey, pull that choke, yank the recoil starter, and that big Honda roars to life in seconds. Demerits? Its hose appears to be very durable, but boy is that thing stiff. It will likely take a lot of use before it softens up a bit.
The RY142300 is a journeyman machine, one that delivers consistent soaping and washing performance. It’s stronger than the Karcher K5, the Worx, and Sun Joe and about equal to the Craftsman (the other electric pressure washers nearby). It’s much heavier than the Craftsman, though most of that weight difference is attributable to its physically larger motor. We suspect that the Ryobi is the more durable of the two machines, again owing to that big bruiser of a motor. Our only complaint with this otherwise fine pressure washer is its spray wand mount on the handle. All it takes is one good bump to knock the wand off. It’s very irritating.
The GPW2700 sailed to an easy victory among the electric pressure washers, not surprising given that this is an expensive and well-made piece of equipment. Its high pressure and volume output enable faster and more thorough cleaning. And those come courtesy of the constant-run motor, which is always turning, not just when you pull the spray wand trigger. This improves trigger response and reduces priming, since the pump is held under constant pressure. Also, the machine has a pressure and flow sensor so that the pump output adjusts to suit the nozzle you insert in the spray wand. All of this adds up to better wash performance.
Although the pressure washer stands for storage or when you need to wheel it for transport, it operates horizontally. Thus, it can’t tip over. And a pivoting hook eases access to wrapping of the 35-foot cord. Our complaint: The hose outlets (both for the spray wand and the garden hose hookup) are close to each other, reducing access to them.
We’ve tested these power washers to clean the undercarriage of a pickup truck and (very carefully) wash some cars. If you do so, be sure to use the white nozzle.
This is a light, easy-to-handle machine with adequate power for mid-duty jobs. We particularly appreciated two features: the large, easy-access detergent tank right on top of the machine, and the whopper of a power cord, 35 feet long. That’s about 10 feet more than on the average electric pressure washer, virtually eliminating the need for an extension cord.
Of all the nozzles we tried on it, we had the best results with the turbo (rotating blast). It proved particularly adept at cleaning concrete. A final design detail that we really like is its slide-on spray wand mount. The gun can’t be knocked off, like it can with other machines.
If you've got a tall house, or tough cleaning jobs ahead of you, consider this entry-level commercial washer from Generac. The company rates it to reach the second floor. Everything about it is outsize, from its tremendous psi and flow rate (4200 psi and 4 gpm, respectively) to its 50-foot steel-reinforced hose.
We're eager to test this product because its predecessor (Worx GG60, discontinued and replaced with this model) did very well, racking up points for light weight, ease of use and a reasonably high effectiveness for such a small machine. We see similar design attributes here, but also more cleaning power with pressure that has been bumped up to 2200 psi (from 2000 psi).
We haven't tested this machine yet, but we're looking forward to it. It's a light-duty 40-volt pressure washer powered by a pair of 6-Ah batteries. It can siphon water out of a pool, lake (or other body of water) or the water can be supplied by a garden hose.
Roy Berendsohn has worked for more than 25 years at Popular Mechanics, where he has written on carpentry, masonry, painting, plumbing, electrical, woodworking, blacksmithing, welding, lawn care, chainsaw use, and outdoor power equipment. When he’s not working on his own house, he volunteers with Sovereign Grace Church doing home repair for families in rural, suburban and urban locations throughout central and southern New Jersey.
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