Pressure washing vs power washing: what is the difference

Pressure washing and power washing use the same machine, and the only technical difference is that a power washer heats the water while a pressure washer does not. In everyday use, most companies own both machines and answer to whichever word you said first. Here is what each term actually means and why the method matters more than the name.

The terms are used interchangeably

Walk into any hardware store and you will see machines labeled both ways. The industry has never settled on a single definition, and most contractors use the words to mean the same thing. So when a company calls itself one or the other, you have learned almost nothing about how it will treat your house. Both machines are built from roughly 1,500 PSI up past 4,000, and both can be dialed down below garden hose pressure with the right tip and the right distance.

What pressure washing is

Pressure washing uses water at whatever temperature it comes out of the spigot, pumped at high pressure to lift embedded dirt, mildew and staining off hard, water-tolerant surfaces. Most machines run between 1,300 and 3,000 PSI. It suits hard, water-tolerant surfaces: concrete, stone, and the walks, patios and pool decks around a home. Used well, it brings back the original color instead of etching it.

What power washing is

Power washing is pressure washing with heated water. A burner on the trailer heats the water to between 130 and 250 degrees Fahrenheit. Heat breaks down anything built on a fat or an oil: grease on a restaurant pad, chewing gum on a sidewalk, oil drips in a parking lot. It does nothing for algae, which is killed by the cleaning solution rather than by temperature or force. Heat also keeps a crew productive in winter and helps a surface dry before the temperature drops.

What soft washing is

Soft washing uses low pressure, typically under 500 PSI, and a cleaning solution that kills mildew and algae at the root. The solution does the cleaning, and the water just rinses it off. This is the method for siding, brick, stucco, painted surfaces and wood fences, because a hard blast drives water behind the boards, lifts paint and scars mortar. It can also scrub the color out of algae without killing it, which is why the same wall greens over again within weeks.

Which surfaces suit each method

• Driveways, sidewalks, patios, concrete and stone: pressure washing with a surface cleaner for even coverage.
• House siding, brick and stucco: soft washing at low pressure with a cleaning solution.
• Wood fences and decks: low pressure with a wood-safe cleaner, never a hard blast.
• Asphalt shingles: never pressure washed, because the granules that protect them come off.
• Restaurant pads, dumpster corrals and gum-covered sidewalks: power washing with heated water and a degreaser.

Why the method matters more than the name

A power washer is not stronger than a pressure washer. Both cover the same pressure range and both can be dialed down below garden hose pressure with the right tip and the right distance. The number on the machine has never been the thing that decides whether your siding survives the afternoon. What matters is the pressure, the solution and the technique used on each surface. The strongest machine on a shingle roof strips granules. On vinyl it drives water behind the courses. On a fifteen-year-old deck it raises the grain. Force is the thing you spend as little of as the job allows. Ask what pressure they are putting on your siding and what the pre-treatment is. A house wash is a soft wash every time, regardless of which word you used when you called. Driveways and concrete are the surfaces that genuinely benefit from pressure washing. Hot water earns its keep on grease, oil and gum, which is almost entirely commercial work.

Common questions

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