An air compressor isn't
the first tool people notice when they come on site. If you're
like me, you try to put it out of the way so you don't have to
listen to it. I might not see my compressor all day long, yet
it's one of the most important pieces of equipment I own.
I work for a remodeling company and do everything from
demolition to painting. Most of the work takes place in
existing buildings so I only frame the occasional partition
wall or shear panel. However, my compressor still gets a lot of
use. It powers a finish gun, palm nailer, and framing gun. It
drives the air hammer I use to chip out tile, an HVLP sprayer,
and a gun and hopper for texturing drywall.
Some of these tasks will strain a small compressor, but it
would be overkill to haul around the kind of unit a framing
crew would use. A two to three horsepower four-gallon model is
a reasonably good compromise; it's small enough to fit in a
crowded truck bed and light enough to lift alone.
Compressors come in all shapes and sizes. Some have a single
"hotdog" or "pancake" shaped tank. Others have one big tank or
a pair of cylindrical tanks. It's impractical to review more
than a small fraction of the available models, so for this
article we tested ten twin stacked-tank compressors. We chose
this type because every company makes them and they're
traditionally the type of unit a small crew would use. I also
wanted to see if there was any difference between oil and
oil-less models, so I tried some of each.
Compressor technology has changed little over the years. An
electric motor drives a pump that pushes air into a storage
tank. An automatic sensor turns the motor on when the pressure
is low and off when it's high. The air leaves the tank, passes
through a pressure regulator, and is fed to the tools through
The tools were tested over a period of several months. I took
them on site and used them for whatever I was working on. I
also loaned them to the carpenters I work with and got their
opinions. Near the end, we gathered the compressors in one
place to measure sound output and recovery time.
All ten compressors ran my pneumatics effectively but some were
more pleasant to use than others. The biggest difference
between models had to do with portability, noise output, and
how the components were positioned.
Motor and Pump
All of these compressors use an electric motor to drive the
pump. The pump contains a cylinder and crank-driven piston. The
piston produces heat and friction, so pumps have traditionally
been lubricated with an oil bath. Most compressors still use
oil, but some models do not. An oil-less compressor contains
"self lubricating" piston rings. The rings are impregnated with
Teflon or a similar material, which reduces friction to the
point where oil is not needed.
Oil vs. Oil-less. There is a
lot of debate about which type of compressor is better. I
prefer to think of this in terms of what type of compressor is
better for the kind of work you do. Oil lubricated pumps are
very durable and can withstand eight to ten years of nearly
continuous use. However, they won't last nearly as long if they
aren't properly used and maintained.
Unless the manufacturer says otherwise, oil-lube compressors
should be operated on no more than a 10-degree slope. If the
angle is steeper the oil runs to the side of the crank housing
and will not splash onto the piston.
Under normal circumstances oil-less compressor pumps will not
last as long as the pumps on oil lubricated models. That said,
I own an oil-less compressor and it's going strong after five
years of regular use. It requires less maintenance because
there's no oil to check or change. I feel better using it
around finished surfaces because there's no oil to drip or
spill. It's not a concern where I work, but oil-less
compressors are easier to start in freezing weather because
there's no oil to thicken in the cold.
However, an oil-less unit is more vulnerable to contaminants
because the bottom end of the cylinder is open to the air. This
type of compressor is not the best choice if you expect to use
it out in the dirt or on a really dusty job site. At minimum,
place it on a clean solid surface, not on a pile of sand.
According to the manufacturer, the Renegade T-200ST is less
vulnerable to contaminants because it has a dirt deflector. We
removed the housings from the oil-less units and examined what
was inside. The deflector looks like an improvement, but it's
impossible to believe it's as protective as the fully enclosed
housing on an oil-lube machine.
Noise output. I often work in
the same room with the compressor, so it's aggravating to use
one that makes a lot of noise. To my ears Makita's MAC2400 and
Campbell Hausfeld's Maxus EX8001 were noticeably quieter than
We used a digital decibel meter to verify my observations. All
ten compressors were tested in the same location and metered
from 6 feet away. As you might expect, they were the loudest as
they strained to put in the last few pounds of pressure. The
results are in the spec table and are in line with how the
tools sounded to me. It's hard to detect a difference of two or
three decibels, but you can definitely hear a difference of
five to ten decibels.
Some carpenters claim oil-less compressors are noisier than
oil-lube models. I don't think this is true, at least not when
the tools are new. We tested three oil-less models and the
specs were all over the place. The Ridgid was the loudest tool
of all but the Maxus was quieter than every oil-lube compressor
except Makita's. The Renegade was in the middle of the
The type of pump may have something to do with sound output,
but what really counts is how fast you run it. The motors on
most of these tools run at or above 3400 rpm. Three of the four
quietest models have motors that run at or below 1725
Air delivery is the volume of air that can be delivered at a
specific pressure. You can use this spec to calculate how many
tools a compressor can handle, but a good rule of thumb for
these models is that they'll run two finish guns or one framing
gun, provided you're not nailing vast areas of sheathing.
According to the manufacturers, a compressor is too small for
the job if it has to run more than 50% of the time. The motor
and pump will be damaged if you overheat them, which will
happen if you run them more than 30 minutes out of each
Air reserve. The tank
contains a reserve of compressed air that allows you to use air
tools when the pump is not running and, for a short time, to
consume more air than the pump produces. If you do it for long,
the tank pressure will fall to the point where air tools no
longer work. All you can do is stop and wait for the pump to
replenish the tank.
The bigger the tank and the higher the pressure, the greater
the reserve. The old standard for stacked tank units was 4
gallons at 125 psi. Many of these compressors hold a greater
volume at higher pressure. As a result, they don't have to
cycle quite as often.
You can boost the reserve by putting a portable air tank in
series between the compressor and tool. I do this when I use an
HVLP sprayer or a drywall texturing gun. It's not a perfect
solution, but it allows me to do more work before I have to
stop to let the compressor catch up.
Recovery time. The compressor
motor automatically comes on when the pressure falls below a
preset "cut in," typically between 90 and 100 psi. The motor
turns off when it reaches the "cut out," the maximum pressure
rating of the machine. The amount of time it takes to go from
cut in to cut out is referred to as "recovery time."
We used a stopwatch to measure the recovery time of each
compressor (See the spec table below). On average, the tools
took 14 seconds to recover. I expected there to be a
correlation between air delivery and recovery time, but it
didn't show up in the specs because there were too many other
things in play. The tools have different size tanks, different
maximum pressure settings, and different cut-in points.
Size in inches(w x l x h)
Campbell Hausfeld Maxus
T-200ST Renegade Pro Series
Compressor Specs (continued)
Tank size (gal.)
Recovery Time (sec.)
Number of air fittings
4.1 @ 90 psi
4.0 @ 90 psi
4.4 @ 90 psi
4.2 @ 90 psi
4.0 @ 90 psi
4.1 @ 100 psi
4.3 @ 100 psi
Campbell Hausfeld Maxus
4.3 @ 90 psi
6.2 @ 90 psi
T-200ST Renegade Pro Series
4.6 @ 100 psi
*Has space for two fittings. Air
fittings supplied by owner.
Ease of Use
Until recently, the major components were bolted to a frame and
the gauges, regulators, and hose fittings were installed like
so much extra plumbing. These days the components are likely to
be more integrated. Just over half of these tools had
roll-cage-style frames and integrated instrument panels. The
frame increases size and weight but it protects the components
from damage. The panel also serves a protective function and
makes it easier to access gauges, regulators, and
Hitachi's EC 119 and DeWalt's D55152 keep an especially low
profile. The integrated panels are tucked between the tanks and
angled upward so you don't have to bend as far to read the
gauges. About half of the compressors come with two air
fittings — it's much more convenient than using a
Mobility. A compressor is
easier to move if it's light and has a well-designed handle.
It's simpler to store and transport if it's small and compact.
If the compressor has a low center of gravity, it's less likely
to fall over when you hit the brakes in your vehicle.
There's a 17-pound weight difference between the lightest and
heaviest compressor; the average is about 66 pounds. Senco and
Rol-Air produce the lightest units, Bostitch and Makita the
heaviest. Thomas makes the most compact compressor. I had no
trouble hauling it on the passenger-side floor of my compact
truck. The Senco and Rol-Air are also quite small, while the
Bostitch and Ridgid are on the large side.
Handles have a lot to do with whether or not the tool is easy
to lift. I like straight handles better than canted ones. All
of the handles were easy to grasp except for Makita's, which in
spite of its fancy rubber grip felt uncomfortable. Lifting any
of these tools into my truck bed was a two-handed job.
Drain valves. Air tanks
should be drained at the end of the day; otherwise condensation
will build up and rust them out. More than once I've had to use
pliers to open the conventional petcocks on old compressors.
The ball valve drains on the DeWalt, Hitachi, and Makita units
are a real step up. They operate smoothly and can be open or
closed with a quarter turn. The other models have conventional
valves, except for the Bostitch, which uses a strange
Air filter. The filter is
designed to keep contaminants from entering the compressor and
causing undue wear on the pump. Every one of these machines is
equipped with a filter, but in several cases it's hanging out
where it can get bashed.
It's much better if the filter is safely tucked away. In most
cases, the filter is placed where it would be hard to hit. The
filter on the Bostitch compressor, however, projects beyond the
roll cage — an accident waiting to happen. The filter on
Makita's compressor is outside, too, but is somewhat more
secure because it's held on with a wing nut. Thomas and Hitachi
removed the issue altogether by mounting their filters under
rigid screw-down covers. They're so well integrated you hardly
notice they're there.
When space is at a premium and easy mobility is a must, I'd go
for the Thomas Renegade Pro-Series T-200ST. This oil-less unit
is of average weight but is the most compact and delivers more
air than all but one of the compressors I tested.
In terms of features, I really liked the Hitachi EC 119. It has
a low, stable profile, space for two air fittings, ball valve
petcocks, a cord wrap, and a large comfortable handle. I also
liked DeWalt's DW55152. It has a ball valve petcock and a cord
wrap, and it is relatively compact with all the components
covered by a housing or tucked inside the protective roll
This is the largest,
heaviest compressor I tested. The filter hangs past
the frame where it could get bashed. It's equipped
with a pair of strange spring-loaded drain
fittings. The fittings are self closing so to drain
the tanks you have to stand there and hold them
open. The cables that hang from the fittings could
easily get hung up on things.Stanley Fastening Systems
The Maxus is the
second quietest compressor tested. It's of average
weight but the well-placed handle makes it easy to haul
around. The motor and oil-less pump ran very smoothly
and are protected by a rear roll bar. The gauges are
easy to see because they face straight up.
The ball valve
petcock on this compressor is tucked away where it
can't be damaged and is the best of the bunch. This
tool has dual air fittings and a cord wrap for on-board
cord storage. A low profile design means it's stable in
the back of the truck, while the frame offers many
convenient grab points.
DeWalt Industrial Tool
This all new
compressor was one of my favorites. It has a smooth
running motor, a low center of gravity, an onboard cord
wrap, and the best handle of any model. The ball valve
petcocks are easy to turn and very accessible on the
ends of the tanks. The exposed location of the valves
may subject them to damage but the integrated air
filter is well tucked away. The EC 119 accepts two air
fittings, but you have to supply them yourself.
Hitachi Power Tools
hit the mark in terms of noise and power consumption.
It's without question the quietest compressor I tested
and draws only 12.3 amps. A transparent drain plug
allows you to check the oil level without using the
dipstick. You can store a hose in the roomy open
interior. On the downside, this tool is somewhat bulky,
and the skid plate sometimes rattled when the pump was
One of two 150
psi models I tested, the CPLDC2540S is a large but
manageable compressor with a well placed handle. It has
dual air fittings and all the parts are tucked within a
metal roll cage and a recessed instrument panel. This
compressor draws only 12 amps.
This 150 psi
oil-less compressor has bigger tanks and higher air
delivery specs than any model tested. The OF45150 has
good grab points for carrying but is bulky and heavy.
It's also one of the louder units. The high center of
balance meant it was not very stable in the bed of my
Ridge Tool Company
The Bull is
light and small, so it's easy to carry one-handed. The
only unusual features on this tool are the stainless
steel petcocks. This is a basic inexpensive compressor,
though the manufacturer also produces a similar model
(D2000HSSV5) with a higher quality pump.
The PC2001 is
very compact, has a comfortably positioned handle, and
is the lightest compressor I tested. The gauges face
upwards so they're easy to read. It's about average in
terms of performance and features. It closely resembles
the Rol-Air model but is equipped with a higher quality
Senco Products Inc.
oil-less compressor is my personal favorite. Everything
about it looks and feels well made. The motor and pump
put out more air than all but one of the other tools,
and it has a quick 12-second recovery time. The filter
is built into the head, so it's totally
Thomas Industries Inc.
Victor Rasillais a lead carpenter for Sattler's
Construction in Walnut Creek, Calif.