Washing a truck and cleaning a sidewalk require different machines.
For removing driveway oil stains, deck or siding mold, wall graffiti or building grime, pressure washers, aka power washers, are the machines for the job. Whether you’re renting or purchasing a pressure washer for home or professional use, you’ll need to decide what type of pressure washer is best based on the work you plan to do.
The three main decisions to make are how much cleaning power you need, whether you want an electric or gas engine and whether you want a machine that uses hot or cold water. You’ll also need to determine whether a consumer or commercial/professional model is best for you based on how often you’ll use it.
Pick your power level
The amount of pressure in the water stream is expressed in pounds per square inch (PSI). The volume of water the pump delivers is measured in gallons per minute (GPM). Multiply the PSI by the GPM and you get the effective cleaning units, or ECU, a useful number for comparing models.
Higher PSI means more cleaning power, and higher GPM means faster cleaning. But keep in mind that more power isn’t necessarily better. It’s smart to pay for only the power you need.
For tasks such as washing your vehicle or cleaning your barbecue grill, a pressure washer with 1 300 to 2 400 PSI will probably do the job. Cleaning an asphalt driveway, concrete lot or street will require at least 3 000 PSI and 4 GPM. Stripping paint or graffiti may require 4 000 PSI. Homeowners will likely never need that much pressure.
Weigh electric vs. gas
For smaller jobs you can perform within power cord distance from a power outlet (or extension cord distance with some models), an electric pressure washer will do the trick. These typically have around 1 400 PSI, with a GPM no higher than 1,5. Quieter, lighter, and cheaper than other options, they’re good for washing stains off of outdoor furniture or cleaning vehicles or vehicle tires, for instance. And they’re virtually maintenance free.
Pressure washers with gas engines typically have upwards of 2 000 PSI and 2 GPM. They’re a better choice for medium- to heavy-duty jobs such as washing concrete sidewalks or the siding on a house.
Consider hot vs. cold water
Cold water pressure washers are a great choice for eliminating mud, dirt, and sand and are much cheaper than their hot-water counterparts. They are not, however, the best option for cleaning oily or greasy surfaces.
Hot water pressure washers are the ticket for larger or more difficult cleaning jobs, especially when it comes to removing oil and grease, which hot water cuts through more easily.
Consumer or professional?
Unlike consumer models, which are designed for occasional use, professional models are intended for regular use and are built and powered accordingly. Units such as this trail-behind model include automatic detergent injection and can be accessorized with extended reach wands, rotating nozzles, surface cleaners and sandblast attachments. Pneumatic tires are available to provide better traction on uneven terrain.
Choosing a nozzle
The size of the nozzle opening dictates the angle of the spray. The smaller the opening, the more concentrated the spray.
Washers with lower PSI values may come with adjustable nozzles. These allow you to adjust the spray while cleaning. You don’t have to change nozzles for different jobs.
Most pressure washers with higher PSI come with several nozzle tips, color coded by spray angle. A small nozzle opening can damage surfaces if you’re not careful.
- Red: The red nozzle has a 0 degree spray, meaning the water comes out highly concentrated. Use it on surfaces such as concrete. The red nozzle can damage softer surfaces or peel off paint (even if you don’t want it to).
- Yellow: The yellow, 15 degree nozzle produces a strong but moderately less concentrated spray. It’s suitable for more surfaces and can be used to wash away stains, mildew and paint.
- Green: The 25 degree green nozzle is commonly used for household cleaning tasks. Because the spray is wider than that of the red or yellow nozzle, it can quickly clean a larger surface.
- White: The white nozzle’s spray spans 40 degrees, so water comes out at a lower pressure. This makes it a good choice when cleaning anything fragile, like windows.
- Black: Use the black, 65 degree nozzle to spray detergent and soap onto a surface before switching to a different nozzle to clean.
For removing dirt, grime and grease and preparing surfaces for painting, a pressure washer beats your garden hose every time (and it saves water). Choosing the best pressure washer for your task will help you get the job done better and faster, and perhaps even save you some money.