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, their 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. $400) earns the greatest number of top reviews, making it our Best Reviewed gas model. It has a powerful 3,100-psi, 2.7-gpm spray, and five quick-click nozzles for 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. It comes with a two-year warranty.
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."
The 6598 is too new to garner a significant number of user reviews; however, it varies from the discontinued Generac 6024 only in terms of color and styling, so reviews of this model can be applied to the 6598 as well. The 6024 is very highly rated on several retail websites, such as HomeDepot.com, where it earns an average rating of 4.4 out of 5 stars in hundreds of reviews. Most owners praise its power and cleaning performance, although a few find the hose stiff.
In addition, reviewers on Amazon.com give the 6024 an overall rating of 4.1 out of 5 stars. Most commend the model's cleaning performance. Some report receiving damaged units.
For those who prefer the durability of a Honda engine and can sacrifice a little cleaning power in exchange, the Ryobi RY80940 (Est. $400) also scores highly among reviewers. In addition to its Honda engine, this 3,100-psi, 2.5-gpm model is designed to reduce the speed of the engine when the trigger is disengaged, which cuts down on noise and fuel consumption. This model also has a five-in-one nozzle that allows you to switch among water-pressure levels. It comes with a three-year warranty, which is relatively long.
The RY80940 earns an average rating of 4.1 out of 5 stars from owners posting to HomeDepot.com. Most praise its engine and relatively quiet noise level, and some like that its handle folds for easy storage. A few report mechanical problems. The RY80940 also earns a nod from MensJournal.com in a comparative test of four models, as well as a recommendation from Roy Berendsohn of PopularMechanics.com. Berendsohn doesn't specifically test the RY80940, but he does test the Homelite UT80432, which he calls nearly identical. He praises the UT80432's cleaning power and front-mounted cleaner jug, but he dislikes that you have to tip the machine to reach the hose inlet.
For those looking to spend a little less on a gas model, the Generac 6595 (Est. $300) is a scaled down version of the 6598. With 2,500 psi and 2.3 gpm, it has a Generac engine and comes with three nozzle tips for adjustable-pressure spraying. It has a two-year warranty.
While the 6595 is too new to garner many reviews, it is identical to the discontinued Generac 6020, except for aesthetic features, so comments about the 6020 are applicable to the 6595. The 6595 earns an average rating of 4.1 out of 5 stars from users posting to Amazon.com, with most praising its cleaning power. Some report that the unit broke down soon after purchase.