The most powerful type of pressure washer is a gas-powered one. According to ConsumerReports.org, gas-powered units can deliver as much as 60 times the water pressure of a garden hose. For washing your home or cleaning concrete, "unless you have a very small house (or a house that's not particularly dirty), it's likely that an electric machine is not powerful enough to do the job," advises Roy Berendsohn of Popular Mechanics.
Higher water pressure means the job gets done faster, with Consumer Reports noting that gas pressure washers finish up to 10 times faster than electric pressure washers. However, a gas pressure washer's powerful spray can more easily damage materials like wood and auto paint. In addition, as with any gas-powered tool, these models need regular engine servicing.
Among gas power washers, the Generac 6598 (Est. $360) earns terrific feedback. It's rated to deliver 3,100 PSI and 2.7 GPM, putting it at the very top end in terms of cleaning power for consumer pressure washers. The inclusion of five quick-click nozzles for different spray volumes and tasks adds extra versatility. In addition, its upright design makes it easy to store, and it has large wheels for easy moving, as well as two detergent tanks. The Generac 6598 comes with a one-year warranty, plus a second year of parts coverage for the motor.
The 6598 earns a recommendation from Mike Aletich, product expert at PressureWashersDirect.com, who praises its Generac-brand engine and durable AR-brand axial cam pump. He also says the frame is balanced and easy to maneuver, and adds that it should last several years if it is stored and maintained properly."
PressureWasherDirect.com's users largely agree. It earns roughly a 4.5-star rating there based on nearly 170 reviews -- mostly from those who have been verified as having bought the 6598 from the site. About 93 percent of users say they would recommend the Generac 6598. The feedback is as strong or stronger at Lowes.com. The reviews there include a number originally posted at the Generac web site, but are impressive nonetheless. It earns a 4.6-star rating based on more than 230 reviews. Again, about 94 percent give this gas pressure washer a recommendation. The rating at Amazon.com is lower (3.8 stars), but that's based on fewer reviews (less than 60). While a few report problems with defective units, the rating is dragged down the most by shipping issues.
For those who prefer the durability of a Honda engine and can sacrifice a little cleaning power in exchange, the Simpson MSH3125-S MegaShot (Est. $400) also scores highly among reviewers. Though the Simpson is also rated at 3,100 PSI, its maximum water output is lower, 2.5 GPM versus 2.7 GPM for the Generac, so the overall cleaning factor is a touch lower.
The MSH3125-S is ruggedly built, with an ergonomic spray gun with a safety lockout. The spray gun can accept one of five included stainless-steel quick connect nozzles. Accessories can be conveniently stored on board, and the 10-inch tires make moving this Simpson pressure washer around a breeze. The pressure washer is covered for one year, with a second year of coverage for the Honda motor. Accessories are covered for 90 days. The Simpson MSH3125-S is an especially good choice for California residents because, unlike the Generac 6598, it is CARB compliant and can be sold in that state.
Reviews are strong. Like the Generac, the Simpson MSH3125-S MegaShot earns a recommendation from PressureWashersDirect.com's Aletich, who calls it "a very versatile pressure washer at a very reasonable price." User reviews at that site are a little more ambivalent about the Simpson compared to the Generac, though 88 percent of the more than 130 that weigh in give it a recommendation. Feedback is better elsewhere, with a 4.3-star rating at Amazon.com based on reviews from nearly 300 owners. HomeDepot.com has even more feedback -- more than 340 reviews -- though that includes feedback from the manufacturer's site. The MegaShot scores a rating of 4.3 stars, with 92 percent giving it a thumbs-up.
For those looking to spend a little less on a gas model, the Generac 6595 (Est. $250) looks like a good bet. With ratings of 2,500 PSI and 2.3 GPM, the cleaning factor will be lower than the gas pressure washers above, but Aletich says that it's a good choice for the "weekend warrior at home." He adds that if you're torn between the low price of an electric pressure washer and the performance of a gas pressure washer, the Generac 6595 can give some of the plusses of both. "If your debating between gas and electric based on cost -- go for this one," he says. "You'll be happy you did!"
Though there aren't a ton of reviews for the Generac 6595, what there is indicates that most users are indeed happy with their choice. Though not devoid of customer complaints, especially at Amazon.com, where the 6595 scores 4.1 stars, most say that both value and performance make this an ideal pressure washer for their needs. Satisfaction at PressureWashersDirect.com and HomeDepot.com are high (though feedback at the latter includes some reviews originally posted at the manufacturer's web site). Regardless, it earns a 4.6 star rating at HomeDepot.com (based on more than 90 reviews). At PressureWashersDirect.com, 96 percent of the 25 owners who leave reviews say that they would recommend it to a friend. Warranty coverage is the same as for the Generac 6598. Like its bigger brother, this gas pressure washer is not CARB compliant.
All of the gas pressure washers profiled above are consumer units. They might be suitable for use by some painting and other contractors, but for heavy-duty, long-term performance and reliability, a commercial pressure washer is a better alternative for most. Commercial pressure washers are ruggedly built and offer a higher cleaning factor than even the most powerful consumer pressure washers. While most consumer pressure washers are subject to shorter warranty terms when used in commercial applications, professional pressure washers are usually fully covered for commercial use as well.
Feedback on commercial pressure washers isn't extensive, but we saw some good reviews for the Pressure-Pro Professional E4040HC (Est. $1,380). This is a super rugged, high-power gas pressure washer, rated to deliver 4,000 PSI and 4.0 GPM. It features a Honda GX engine and a CAT Triplex Plunger Pump. It's built on a weld-free, aircraft-grade aluminum frame, which carries a lifetime warranty. The engine is covered for three years, while the pump for two. Accessories, which are covered for 90 days, include 50-feet of steel re-enforced, non-marking hose and a spray gun that can accept the five included quick-connect nozzles.
Mike Aletich at PressureWashersDirect.com says that the Pressure-Pro gas commercial pressure washer is "an excellent professional pressure washer choice in this price range." His site is where we also spotted the most user feedback, more than 50 reviews, with 95 percent saying that they recommend the E4040HC. At Amazon.com, we spotted nearly a dozen additional user reviews, with all owners giving this gas pressure washer a 5-star rating. It's CARB compliant, so it's another good choice for California residents.