Choosing The Right Pressure Washer
Pressure Washer Comparison
You face a lot of decisions in choosing a new pressure washer.
Don't be intimidated by all of the terms and specifications, but
recognize what facts you need to know to make a good decision.
The most important thing to know is that your pressure washer
must match the work you intend to do. If you pressure washer is
too large or powerful, you have wasted money and you could
damage what you are cleaning. If your pressure washer is too
small, it will take too long to do the work and you will lose
money and time. That is the simple truth.
Let's start by looking at the different choices you will have to
make when buying a pressure washer:
1. Gasoline vs Electric pressure washers
2. Hot Water vs Cold Water pressure washers
3. PSI vs GPM vs CU ( Pounds per square inch vs Gallons per
minute vs Cleaning Units)
4. Belt Drive vs Direct vs Gear Driven pressure washers
5. Portable vs Stationary pressure washers
6. Wobble vs Axial vs Camshaft Pump
7. Heavyweight vs Lightweight pressure washers 8. Home Model vs
Contractor Model pressure washers
Gasoline vs Electric: Most pressure washers are either powered
by an electric motor or a gasoline engine. A few are diesel
powered. Electric pressure washers require little maintenance
and are very quiet. They require a source of power nearby
(because the cord length is limited). They can be used indoors
without any problem. You can have electric units with lots of
power, but most electrics are small units designed for specific
jobs, such as mobile detailing or deck cleaning. Gas units, on
the other hand, can be extremely portable. They are designed for
outdoor use and can be built to deliver tons of cleaning power.
They can be somewhat loud, but your customers expect to hear
some noise while you are working. Gas-powered pressure washers
are used for cleaning concrete (called "flat work"), deck
cleaning, fleet work, kitchen hoods and ducts, or any other
pressure washing job that requires portability.
Hot Water vs Cold: Most pressure waters are cold-water
portables. Cold water, along with the right cleaners, can do
most jobs. Some jobs, like removing heavy grease or stripping
off finishes, just go better with a hot water pressure washer.
Hot water will enable you to cut about 30% off the time it takes
to do ANY job. The pressure washing business is all about time,
not spending less on your tools. If you have the right tools,
you can compete with other contractors and get done with each
job in the shortest amount of time. Many new pressure washing
contractors make the mistake of under-buying their tools to save
money. Most experienced pressure washing contractors over-buy
their tools and make the difference back in no time with the
added power and features. If all you are going to do is clean
and seal wood, just buy a cold water pressure washer. If you are
washing anything else, such as houses or hoods or trucks or
concrete, consider a hot water pressure washer. If you already
own a cold water machine and want to have hot water, you can
call us and buy a "hot box" which will heat the water coming out
of your cold pressure washer.
PSI vs GPM vs CU: First of all, let's explain the acronyms. PSI
stands for Pounds per Square Inch. This is the pressure rating
of your pressure washer. GPM stands for Gallons Per Minute, the
flow rate of your pressure washer. CU stands for Cleaning Units,
which is PSI multiplied by GPM. All of these terms refer to the
power of your pressure washer.
To clean effectively, a pressure washer must provide 'agitation'
to scrub off the dirt and 'flow' to rinse it away. Think of the
pressure (PSI) as the agitation that is applied to the surface
that you are cleaning and think of the flow (GPM) as the rinsing
force that carries the dirt away.
Homeowner pressure washers tend to run between 1200 and 2700
PSI. Contractor-grade pressure washers tend to run between 3000
and 5000 PSI. More power means faster work, but more power also
means more potential for surface damage. Wood decks, for
example, are often cleaned at pressure as low as 300 PSI because
3000 PSI will rip the wood to shreds. Most contractors will
settle for 3000 PSI because that amount of pressure is adequate
for most jobs. Truth is that most contractors would prefer to
have 3500 or even 4000 PSI if they could get it.
GPM is much more important to most contractors than PSI. Since
most contractors use cleaning chemicals to do most of their
pressure washing work (the fastest method) their job becomes one
primarily of rinsing rather than washing. The cleaners do all of
the cleaning, and the contractor rinses the dirt away. When you
think about that method, you realize that the more flow you
have, the faster the job is rinsed. Therefore, most experienced
pressure washing contractors recognize that GPM is more
important to them than PSI.
PSI (power) will help you break the chemical bond between the
cleaning surface and the dirt. Once the bond is broken, the
extra PSI does nothing to speed up the cleaning time.
The higher the GPM, however, the more surface area a pressure
washer can clean. For example, a 2000-PSI model with a 2 GPM
flow rate might clean approximately 5-7 square feet per minute.
If the same unit had a 3 GPM flow rate, it might clean 8-10
square feet in the same amount of time.
In this business, contractors sell "the finished job". The
contractor who gets that job done in two hours might be making
$50 per hour. The guy who gets the same job done in one hour
makes $100 per hour. Which one do you want to be?
Dealers of homeowner pressure washers like to refer to CUs when
they show you a pressure washer. This number is the result of
multiplying the PSI by the GPM. If you have a pressure washer
with 3000 PSI and 4 GPM, you have 12000 CUs. For homeowner
pressure washers, this is a good comparison of the power you are
buying. For professionals, CUs have little meaning. GPM is most
important, and PSI is less important, and the CU formula makes
them both equal. The best solution is to talk to a dealer who
really understands what you are trying to pressure wash because
he will steer you to the right GPM and PSI for the job.
Belt Drive vs Direct vs Gear Driven: The gasoline engines used
for pressure washers all run at around 3450 RPM. In a Direct
Drive pressure washer that pump is bolted to the engine shaft,
so it spins at the same 3450 RPM. In a belt drive unit, the
engine is tied to the pump through pulleys and a belt and the
speed of the pump is reduced to either 1700 RPM or 1400 RPM. In
a gear-driven machine, the engine delivers power to a
transmission that in turn spins the pump at a reduced speed
(1700 RPM).
Direct drive pressure washers transfer the vibration of the
engine directly to the pump as well.
The faster pumps of direct-drive machines are spinning so fast
that they cannot draw water from a tank or a lake very well.
They tend to work fine when the water is forced into the machine
(like when you hook it up to a hose from the house).
The slower moving pumps (belt driven or gear driven) work less
and wear less, so they tend to last many years longer. They will
also pull water to the machine from a tank, so your pressure
washer shouldn't ever be starved for water (a problem that
results in destroying the pump).
Gear driven pumps still transmit the engine vibration to the
pump because everything is hard-bolted together. This kind of
pressure washer has not become popular since it was introduced
because there is obviously one more part to break in the system
- the transmission.
Portable vs Stationary: Stationary pressure washers are used in
car washes, factories, etc. They are installed in place and
never move. Portable pressure washers are used by contractors
who travel to the customer to do the work. There is a crossover
model called a skid unit - a stationary pressure washer designed
to be installed on a trailer so that it can be taken to the
customer's site for the work. The most common pressure washers
for contractors to use are cold water portable pressure washers
(for small residential work) and hot water skid units (for large
commercial work or high-volume residential work).
Wobble vs Axial vs Camshaft Pump: Since your pump is the heart
of your system, it is critical to understand what you are
buying. Every pump manufacturer makes several grades of pumps -
Good, Better, and Best.
The Wobble design requires a piston to push against the pressure
in the pump and the pressure of a spring. This is an inexpensive
design to build, but it is relatively inefficient, too. This is
the design found on most homeowner pressure washers. It is
designed to work for limited hours at a time and very limited
hours per year, which is OK for a homeowner but doubtful for a
contractor who wants to pressure wash every day. Wobble pumps
tend to last for around 300 hours before needing extensive
service or replacement.
The Axial design is similar to the wobble design with a couple
of important differences. Most axial pumps have larger oil
reservoirs and bearings, which allow them to be used for longer
periods of time and more hours per year. They still are
inefficient (like the wobble) but several lower-priced
contractor-grade machines work fine with the axial design. Axial
pumps tend to last for about 600 hours before needing service.
The Camshaft design delivers the most power and durability of
all these designs. It uses connecting rods on a cam with large
bearings like a car engine, so it runs cooler and lasts longer.
It is able to hold up to continuous use for hours and hours as
long as it is kept cool. Cam pumps tend to run for 1000 hours
before needing service, and tend to last 2000 hours before
needing extensive service or replacement.
Heavyweight vs Lightweight: If you are buying a portable
pressure washer, it makes sense to pay attention to the weight
of the unit. After all, you are the one who is going to lug it
all around and move it into and out of your truck. Aluminum
frames can be fragile, and steel frames can be heavy, so talk to
your dealer about how you are going to transport the pressure
washer. He may be able to steer you to a good solution for your
needs.
Home Model vs Contractor Model: The final choice for you to
think about is durability. We have already discussed the
difference in pumps, even from the same pump manufacturer. The
cheapest pressure washers usually have the cheapest pump, which
won't hold up well for most contractors. There are other
considerations that you need to think about, too.
The finish of the machine can be very important. Powder coating
holds up better and lasts longer than painted frames. Steel
frames rust. Aluminum or stainless doesn't. Aluminum can be
bent, steel is very rigid. This particular choice will vary
depending on the pressure washers preference.
For pressure washers that will be used at least 20 hours per
week and sometimes up to 8 hours in a day, the lower priced
machines just won't last very long. They come with inadequate
parts throughout, such as the unloaders, pumps, and even the
engines. Just because it says "Honda", for example, doesn't mean
that all Hondas are the same. This is where Grandpa's "you get
what you pay for" saying really is true.
If you buy a $900 pressure washer and you get six months use out
of it, that purchase cost you $150 per month. If you bought a
name brand commercial-grade machine of the same specifications
for $1600 and you got 5 years of use from it, that purchase cost
you $27 per month. Which one is less expensive?
Let me relate some of my own experiences. As a pressure washer
dealer, I see homeowners dragging in dead machines that are only
a few months old every week. These machines cost more to fix
than to replace, so my 'boneyard' is full of discarded homeowner
units.
I recently sold two old pressure washers that I used when I was
a contractor and didn't want any more. They were each 12 years
old and each ran like a top. One had needed only routine
maintenance over it's life. The other had to have the pump
completely rebuilt about three years ago. They were both
belt-driven units with AR pumps and Honda engines. I paid about
$1500 for each and sold them for about $300 each. When I added
up all of the maintenance costs and the purchase price and then
subtracted what I got for them when I sold them, those pressure
washers costs me about $16 per month to own. Is there a better
deal than that anywhere?
If the bottom line for you is how much cash you have to fork
over right now, consider an alternative. A reputable dealer can
get you into a quality pressure washer on a lease or finance
contract. In the long run, you are better off with the better
pressure washer. You will spend less of your cash today, and
less over the life of the pressure washer - even with the
interest added on.