Sun Joe SPX3000 vs Greenworks GPW1800

These are the two corded pressure washers in our registry, and they sit at opposite ends of the same argument. The Sun Joe is the stronger machine. The Greenworks is the only one whose numbers have been checked by anybody other than the manufacturer. On most surfaces that first fact decides it. On one surface it is the second.

The short answer

The two spec sheets, side by side

Cleaning units, because PSI on its own tells you nothing

Pressure moves dirt; flow carries it away. A washer with high pressure and no flow etches a line into concrete and cleans nothing around it. The industry shorthand for the two together is cleaning units, and it is simply the product of the pair.

The certification is the Greenworks' real feature

Greenworks is the only washer in our registry carrying a PWMA certification, which means the 1800 PSI and 1.1 GPM have been verified rather than asserted. Everywhere else in this category you are comparing one marketing department's maximum against another's.

It also publishes things nobody else does: a maximum inlet water temperature of 104 F, an inline GFCI on the cord, 8 inch wheels and full assembled dimensions. Sun Joe publishes a weight and a detergent capacity that Greenworks does not, so the disclosure runs both ways — but only one of them has been audited.

The one job where the weaker machine wins outright

On vinyl siding the usual ranking inverts. The Polymeric Exterior Products Association publishes no safe PSI at all and warns that water driven behind the panels rots the sheathing underneath. The job is detergent and rinse, not pressure.

That makes 1,980 certified cleaning units a feature. It also makes Greenworks' missing soap tank capacity genuinely annoying, because detergent volume is what a siding job runs out of. Both machines ship a 0 degree tip and the Greenworks adds a turbo nozzle; neither belongs anywhere near vinyl. The full treatment is in pressure washers for siding.

Who should buy the Sun Joe SPX3000

Driveways, patios, concrete and anyone who cleans with detergent regularly. 2,436 cleaning units is the higher figure, two removable 0.9 liter tanks let you carry two mixes, and the Total Stop System shuts the pump off between trigger pulls. 24.3 lb is published, which Greenworks does not match.

Buy it knowing it carries no certification, that Sun Joe lists the model at both 13 A and 14.5 A across variants, and that the 2-year warranty is a year shorter.

#ad Check the Sun Joe SPX3000 Electric Pressure Washer price on Amazon — how we're funded.

Who should buy the Greenworks GPW1800

Siding, painted timber, cars, garden furniture and anything you would rather not strip. PWMA certification means the figures are real, 60 ft of working radius is the longest here, 8 inch wheels roll across a lawn between elevations rather than digging in, and the 3-year warranty is the longest.

Buy it knowing 1.1 GPM is the lowest flow we hold specs for, and that Greenworks publishes neither a weight nor a soap tank capacity.

#ad Check the Greenworks GPW1800 1800 PSI Corded Pressure Washer (PWMA Certified) price on Amazon — how we're funded.

Deciding by surface

What we cannot tell you

We have not run either washer. Greenworks publishes no weight, no soap tank capacity and no Total Stop System detail; Sun Joe publishes no certification, no inlet temperature limit and no wheel size. Neither publishes a decibel figure or a pump type. Cleaning units are a useful comparison and not a standard: they say nothing about nozzle quality, pump durability or how either machine behaves after three seasons.