Power washers

For those who remember the world before such conveniences as the TV remote control and the drip coffee maker, it can be said that power washers (or pressure washers) are cut from the same cloth i.e., they’re so convenient and versatile that you wonder how you managed to go so long without. Adaptability is the name of the game. Power washers can be used to clean your home’s brick or stone, its aluminium or vinyl siding, the stained or even unpainted wood on the deck, your automobile, boat or RV, the cement driveway and more. They do a better job than hand washing and they definitely do it faster.

Of course, the problem with buying a washer, particularly your first one, is determining what to buy (and how much to spend). To get a handle on the problem, start by determining the “why”, or in other words, what will you be doing with your washer? Remember that a gas powered washer strong enough to strip paint is fine, but how many times are you going to need to strip paint. Buying a smaller, less expensive machine for regular use and renting a larger machine for those few and far between big jobs may be much more practical and cost effective.
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First a few terms
How they work
Then the job
Types
Characteristics
Tips
Maintenance and storage
Accessories
Guarantees

First a few terms

PSI: Pounds per square inch is, in this particular case, a measure of the strength of the spray coming out of the nozzle. To put it into perspective, a regular garden hose has a pressure of about 40 PSI, a low-end electric power washer is about 1000 to 1200 PSI and a high-end consumer gas model operates from 2800 to 3500 PSI.

GPM: Gallons per minute or flow rate is, as the acronym implies, a measure of the volume of water going through the system and out the nozzle. Remember that GPM is as important a measure as PSI. A high-powered machine that can only handle water flow measured in tablespoons isn’t going to get you very far. A rate of “3” or more is a very good GPM rate, although anything above “2” is usually more than adequate for most domestic jobs.

CU: Cleaning units is a measure of power washer performance and is calculated by multiplying the PSI x the GPM. In this case, the higher the rating, the bigger the area you’ll be able to cover in a given amount of time.

How they work

At the back end, power washers draw water from a source (usually an outdoor faucet, but it can be from a standing body like a pond, a lake or even, for really small jobs, a bucket) and, at the front end, pumps it through a nozzle at a much higher pressure than is available from regular sources such as a municipal water supply or an artesian well.

The increased pressure, coupled with any one of a number of specialized nozzle configurations, produces a spray that will simply wash the car or, in the more powerful modes, strip layers of paint off a wall or a deck. In fact, concentrated water sprays can be made so powerful that, in certain industrial uses, they’re used to cut through steel plate.

Then the job

The following table is designed solely to provide an idea of the range of jobs that are possible with power washers of various capacities. Thus, if the main purpose is to buy a machine to wash vinyl siding on a two-story building, a 2000 PSI machine will considerably outperform a smaller 1000 PSI model, although both machines may appear below in the category of “light work”.
Light work1000 à 2000 PSIwashing cars, lawn and patio furniture, vinyl siding
Medium work2100 à 2700 PSIthe above + removing grease and oil from concrete
Heavy work2800 à 3500 PSIthe above + stripping paint

Types

As with many home power tools, power washers are divided into gas-powered and electric models. Of the two, the gas-powered models offer a wider range of power levels than their electric counterparts.

Electric power washers

Electric power washers are designed mainly for consumer, versus commercial, use and run the gamut from the smallest model used to wash the car or the patio furniture, to the more powerful machines that can wash the vinyl siding on a two-story home. They’re generally less expensive than gas models and produce flows in the 1000 to 2000 PSI range. They operate on standard 110 volt from regular electrical outlets.

Motors
Electric motor power is rated in amperes. Although there are power washers that are rated higher and/or lower, generally washer motor power ranges from 13 to 22 amps. As well, electric power washers are equipped with either universal or induction electric motors. The chief difference between the two lies in the fact that induction motors, lacking carbon brushes, are completely maintenance free and tend to last longer than universal motors and universal motors need periodic, albeit minor, motor maintenance.

The advantages:
  • Electric power washers are mostly smaller, lighter and easier to carry around.
  • They require less maintenance than gas-powered models.
  • Electric washers are quieter than gas-powered washers.
  • They need less space and no special preparation when put in storage for both short and long periods.
  • If the need arises, electric power washers can be used indoors as they don’t produce toxic fumes.

The drawbacks:
  • To operate, electric washers need to be near an electrical power outlet, so their range can be limited.
  • Less power means slower operations. Gas models with their higher PSI’s and GPM’s will do the job a lot faster.
  • Less penetrating power. Don’t expect to be able to strip paint or stain off a deck with an electric model.

Gasoline-powered washers

Gas-powered washers are designed for both consumer and commercial users. For the consumer, machines in the 5.5 horsepower to 13 horsepower, 2000 to 3000 PSI and 3 to 4 GPM ranges are usually sufficient for most tasks. Due to their higher weight, they’re mounted on wheeled frames that make them mobile and can serve as attachment points for hoses and accessories.

The advantages:
  • Although gas-powered washers are more expensive, they’re also more powerful and versatile.
  • Because they’re self-contained, they can be used almost anywhere.

The drawbacks:
  • Gas powered machines can’t be used indoors because of the exhaust gasses. If you must use one indoors, make sure the space is very well ventilated.
  • Gas powered washers are much heavier than electric models. This is compensated for by the fact that they’re mounted on metal frames on wheels, however, the weight factor must be considered if you need to transport the machine from place to place.
  • Gas powered machines require more maintenance than electric machines.
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