Best pressure washer for siding

Every other surface on this site rewards pressure. Concrete wants it, a stripped deck tolerates it, a car needs it kept down but survives a mistake. Siding is the one job where the failure is hidden inside the wall, and where the trade body that represents the product refuses to print the number everybody searches for.

The short answer

The number nobody publishes

Start here, because it changes what a roundup on this topic is allowed to say. The Polymeric Exterior Products Association — the trade body formerly known as the Vinyl Siding Institute — publishes cleaning and maintenance guidance for vinyl siding and names no PSI figure anywhere in it.

What it publishes instead is this: "Some siding manufacturers do not recommend power washing, while others have limits on the pressure (PSI) and cleaners that can be used."

What actually decides a siding washer

If pressure is not the criterion, four other things are. In order of how much they matter on a wall:

1. Detergent capacity and delivery. Siding comes clean because a cleaner sits on it and lifts the film, then gets rinsed. A machine that holds more solution and applies it through a proper soap nozzle does the job; one that relies on the jet does not.
2. Working radius. Hose length plus cord length is how far you get from the spigot and the outlet before you have to move both. A house has four sides and usually one convenient tap.
3. Flow, not pressure. Rinsing a two-story wall is a volume job. Gallons per minute is what carries the solution off the panels before it dries.
4. The lowest output you can still work with. Cleaning units — PSI multiplied by GPM — is the single figure that compares two washers, and on siding you want it low rather than high.

Note what that arithmetic does to the usual ranking. On concrete the 6,000-unit machine is the winner and the 1,980-unit machine is barely adequate. Here the order is inverted, and the cheapest tool in the set is the most appropriate one.

The three, on published figures

1. Sun Joe SPX3000 — the most detergent on the wall

Two removable 0.9 liter tanks is the whole argument. No other washer in our registry publishes a detergent capacity at all, and on siding the solution is what does the cleaning — the water is only there to put it on and take it off again.

Two tanks rather than one also means you can carry a siding solution and a second cleaner without emptying and rinsing between jobs, and both lift out, which is the difference between refilling at the tap and refilling at the machine.

The rest holds up for the job: five quick-connect tips including the 40 degree and soap nozzles you actually want, a Total Stop System that shuts the pump off when you release the trigger, 24.3 lb to carry round a house, and a 13-amp motor on a 35 ft cord.

Against it: at 2,436 cleaning units it is the more energetic of the two corded machines, its 20 ft hose is the shortest here, the 0 degree tip in the box has no business on a wall, and the warranty is two years against the Greenworks' three. Sun Joe also publishes no maximum inlet water temperature.

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

2. Greenworks GPW1800 — gentlest, and independently certified

One thousand nine hundred and eighty cleaning units is the lowest published output we hold specs for, and the PWMA certification is what makes that number worth something. A certified figure has been verified by a third party rather than measured by the marketing department at the moment of peak flow.

On a site that computes with published specifications, a certified spec is a genuinely better input than an uncertified one, and this is the only pressure washer in our registry that carries the mark.

It is also the longest reach here: a 25 ft hose plus a 35 ft cord is 60 feet of working radius, five more than the Sun Joe, which on a house is one fewer move of the extension lead per elevation. The 8 in wheels roll across a lawn instead of plowing into it, the cord has an inline GFCI, the tool warranty runs three years, and Greenworks publishes a 104 F maximum inlet water temperature that most makers leave blank.

Against it: 1.1 GPM is the lowest flow of the three, and rinsing a two-story wall before the solution dries is exactly the job that wants flow. Greenworks publishes no weight and — the omission that costs it first place — no soap tank capacity, which is the single most important specification for this surface. It also ships a turbo nozzle, which should stay in the box.

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

3. Greenworks 60V 3000 PSI — the cordless case, honestly

There is a real argument for cordless here that does not apply on a driveway. Washing a house means walking all four elevations, and a corded machine means dragging 35 feet of lead and a hose round every corner, past every downspout, twice.

The problem is what you are buying. Six thousand cleaning units is three times the gentlest machine here, and on vinyl you would spend the entire job in Eco mode at a published 2200 PSI and 1.0 GPM — 2,200 units, which sits between the two corded washers. You are paying for output that must stay switched off.

The other constraint is the 30 minute published runtime against two machines that run as long as they are plugged in. A house is not a 30 minute job, so plan on a second battery — the wider version of that trade-off is in corded vs cordless pressure washers.

Greenworks publishes no detergent arrangement, no nozzle list and no weight for this machine, which on this particular surface leaves the three specifications that matter most all blank.

#ad Check the Greenworks 60V 3000 PSI Cordless Pressure Washer price on Amazon — how we're funded.

How to actually wash siding

These are PEPA's published instructions, not ours, and they matter more than which machine you bought.

• Hold the wand straight at eye level. PEPA's wording is direct: "Hold the power washer straight at eye level. Do not aim the stream upward, as this can force water behind the siding panels." Lap siding overlaps downward; a stream angled up goes under the lap and into the wall.
• Start at the bottom and work up. "Start at the bottom of the house and work your way up to prevent streaking." This is the opposite of the instinct, and the instinct leaves tracks.
• Rinse before it dries. "Rinse the cleaning solution completely before it has a chance to dry on the surface." On a hot, sunny wall that is a shorter window than you expect, and it is the reason flow matters.
• Stay away from the openings. "Be cautious around windows, doors, electrical wiring, and plumbing. Many manufacturers caution against pressure washing these areas."
• Consider not using the washer at all. PEPA's own preferred tool is simpler: "A soft cloth or a long-handled brush with soft bristles is ideal." On a single-story wall that is a genuine option.

What not to put on the wall

PEPA publishes a specific list of substances that damage vinyl siding, and it is worth reading before you buy a cleaner rather than after:

• Cleaners containing organic solvents
• Undiluted chlorine bleach
• Liquid grease remover
• Nail polish remover
• Furniture polish

Undiluted chlorine bleach is the one that catches people out, because bleach is the standard answer to the green film on a north-facing wall. The word doing the work in that line is "undiluted".

Two nozzles, and only two

All three machines here ship a 0 degree tip and the Greenworks GPW1800 adds a turbo nozzle. Neither should ever touch siding: a pencil jet at close range gouges the finish and will drive straight through a caulk seal.

Use the soap nozzle to apply, and the 40 degree tip to rinse. Our pressure washer nozzles guide sets out what each angle does and which surfaces each one is for, and the main pressure washer roundup compares these machines across every surface rather than just this one.

The second story, and why reach is a real spec

PEPA's eye-level instruction has a consequence nobody mentions when they sell you a pressure washer: it rules out cleaning an upstairs wall by standing on the lawn and pointing the wand up at it. That is precisely the stream angle the guidance tells you to avoid, and precisely how water gets behind the panels.

Which leaves three options, none of which is a specification on a box. Work from a ladder and accept holding a pressurized wand at height, with the recoil that comes with it. Use a telescoping extension wand, so the nozzle rises to the wall while you stay on the ground. Or clean the upper story with PEPA's own preferred tool, a long-handled soft-bristle brush, and save the washer for the ground floor.

None of the three machines here publishes an extension wand in the box, and none publishes a maximum working height. If a second story is the reason you are buying, that accessory is a separate purchase to budget for, and it is worth confirming the thread fits your wand before you order.

Who should skip all three

If your siding is fiber cement, painted wood, stucco or a manufacturer that explicitly says not to power wash, this page does not cover you and neither does PEPA's guidance, which is written for vinyl. Check the panel maker's own literature. If the answer there is "do not power wash", the soft brush is not a compromise, it is the instruction.

What we cannot tell you

We have not washed a house with any of these machines, and we have not tested any of them against any surface. There is no published safe PSI for vinyl siding from PEPA or from us, and the limit that applies to your wall is whatever your siding manufacturer publishes. Greenworks publishes no weight, no soap tank capacity and no Total Stop System detail for the GPW1800, and neither a nozzle list nor a detergent arrangement for the 60V machine. Sun Joe publishes no maximum inlet water temperature. Cleaning units compare output; they do not predict damage, and no maker publishes a figure that does.