Some of the more powerful pressure washers we recently rated are capable of splintering wooden tables. All are at least forceful enough to harm a car’s paint.

Yet it’s just that kind of oomph that enables pressure washers to blast away deck mildew, driveway stains and other grunge a hose can’t touch, while cleaning chairs, siding and other items more quickly and easily than you could with a scrub brush.

Pressure washers use a gas engine or electric motor, pump and concentrating nozzle to boost water pressure from your garden hose as much as 60 times. Gas-powered models are generally the strongest, typically putting out 2,000 to 2,800 psi (pounds per square inch) of pressure, compared with 1,300 to 1,700 psi for electrics. For as little as $90 for electric machines and $300 for gas, owning a pressure washer is a tempting alternative to renting one for $50 to $90 per day.

Lower prices and less upkeep explain why 60 percent of buyers choose an electric pressure washer. But go to one of the big-box stores – where most pressure washers are sold – and you’ll find that gas models dominate. The reason: their advantage over electrics in cleaning power. Much higher pressure allowed the top-performing gas machines in our tests to clean a grimy concrete patio three times faster than the fastest electrics. And gas models were up to 10 times faster at stripping paint off vinyl siding, a test we used to simulate tough stains.

On the downside, all of the gas models required more caution and control than the electrics to avoid damaging surfaces.

Here are some top performers from both camps:

¢ Gas-powered. If you need a machine for big jobs, where cleaning speed and stain removal count, look first to a gas-powered pressure washer. Top-rated among tested models was the Troy-Bilt 42133 ($400) – the fastest machine in our lineup. Slightly slower – and, at $500, more expensive – was the Karcher G 2400 HH. Scoring highest in stain removal were two washers from Excell – the XR2600 ($400) and the XR2750 ($500). If low price is worth a bit less performance, the very good Campbell Hausfeld PW2200 is a CR Best Buy at $300. It comes with a soap tank, which saves you the hassle of using separate containers.

¢ Electrics. For small decks and patios, furniture, and other smaller jobs that emphasize cleaning over stain removal, an electric pressure washer should suffice. None in our lineup could match the cleaning speed of the higher-rated gas models, but three offer a very good blend of power and convenience. Wheels make the Karcher K 2.97 M ($150) and Husky 1750 ($180) easy to move between jobs, while low price ($90) and comparatively light weight (14 pounds) help position the Campbell Hausfeld PW1345 as a CR Best Buy.

Whether you buy a gas-powered or electric pressure washer, don’t be bowled over by the lofty numbers some retailers and manufacturers use to tout water pressure and volume. (Some talk about “cleaning units,” which are simply the pressure multiplied by the volume.) As our testing demonstrated, some top-performing machines had less of both than lower-scoring models.

Do, however, look for convenience. In addition to soap tanks and wheels, tool and cord storage is a plus, as is an adjustable nozzle. (A twist is all it takes to change spray width or pressure.)

And do take precautions to protect yourself and what you’re cleaning. Wear safety glasses or goggles, shoes, and – with gas models – hearing protection when working with a power washer. Start with the nozzle 2 feet away from the cleaning surface, moving closer as needed, but no closer than 6 inches.