Professional cleaning at a do-it-yourself price has helped move pressure washers beyond the tool-rental shop and into your local home center.
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. That lets them 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. For as little as $90 for electric machines and $300 for gas, owning one 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 gas machines have roughly twice the cleaning power, which is the main reason you'll see fewer plug-in models at the big-box stores where most pressure washers are sold.
Weeks of tests on an array of outdoor surfaces we carried out four years ago confirmed that gas-powered machines have a clear performance edge over electrics. But more pressure also means more chance of injury with any pressure washer (see Protect yourself and your belongings, below). Especially with gas models, it's easy to damage what you're cleaning. Here are the details:
Water pressure is typically measured in pounds per square inch (psi). Gas-powered models typically put out 2,000 to 2,800 psi of pressure compared with 1,300 to 1,700 psi for electric models. Much higher pressure allowed the top-performing gas machines to clean a grimy concrete patio three times faster than the fastest electrics. 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 splintering and etching wooden tables and other surfaces.
All the gas pressure washers produced at least 85 decibels (dBA), the threshold at which we recommend hearing protection. Electric models averaged 78 dBA when running and are silent with their triggers released, since doing so stops the motor.
Injuries involving pressure washers recently rose from 2,000 to 3,000 per year, according to the Consumer Product Safety Commission. Typical mishaps include chemical burns to the eyes and skin abrasions. You can also be injured by material shot back at you. To protect yourself and what you're cleaning: