Question 1

What is more important on a pressure washer: PSI or GPM?

Accepted Answer

Both matter together—multiply PSI × GPM to get Cleaning Units (CU). PSI (pounds per square inch) is the stripping force that breaks grime loose, while GPM (gallons per minute) is the water volume that flushes dirt away. For washing cars, you actually want moderate pressure (1,500–2,100 PSI) and higher GPM (1.5–1.76+ GPM) so you don't damage paint.

Question 2

Why do upright electric pressure washers keep tipping over?

Accepted Answer

Many older 2-wheel upright carts mount the heavy motor high off the ground and connect the high-pressure hose near the top handle. Every time you tug the hose, leverage pulls the cart onto its face. Choosing a 4-wheel low-center-of-gravity unit (Westinghouse ePX3100v), a cube (Kärcher K1700 Cube), or a flat jobsite cage (DEWALT DWPW2100) solves tipping completely.

Question 3

Do I need a gas pressure washer or will a 120V electric model clean my driveway?

Accepted Answer

A 120V electric pressure washer (2,000–2,300 PSI) will clean patios, decks, siding, cars, and small walkways well using a 15° or turbo nozzle. However, if you have a large two-car concrete driveway or want to spin a 15-inch steel surface cleaner (SIMPSON 80165) at full speed, a 3,200 PSI / 2.5 GPM gas washer (SIMPSON MegaShot MSH3125) finishes the job in less than half the time.

Compare Pressure Washer Brands: Lineups, Specs & Trade-Offs

All 8 pressure washer brands

Westinghouse

SIMPSON Cleaning

Sun Joe

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DEWALT

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Generac

WORX

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