When you set out to buy an air compressor, you are faced with one important choice, to buy an oiled or oil less air compressor.
Is there any difference? If so, then what is it?
This “oil vs oil-free” debate isn’t going to resolve any time soon, while technology has kept evolving continuously.
In this article, we shall discuss the differences between oil and oil less air compressors, their facts and uniqueness, lastly their advantages over each other.
So without further ado.
- 1 How Do Air Compressors Work?
- 2 Oil-Less Air Compressors.
- 3 Oil Based Air Compressor.
- 4 Life Expectancy Comparison.
- 5 Let’s Compare The Noise Level.
- 6 Usage.
- 7 Weather Advantages And Disadvantages.
- 8 The Purity Of Air.
- 9 Any Potential Problem With Airlines?
- 10 How To Maintain An Air Compressor?
- 11 The Secret For A Longer Lifespan.
- 12 Last But Not Least, How To Choose One?
How Do Air Compressors Work?
An air compressor works by drawing air in due to the downstroke of the piston, while the upstroke compresses the air into the storage.
Don’t confuse the working of this piston with that of a car. Nevertheless, both piston does require little lubrication to prevent any friction/seizing between the wall of a cylinder with the metal-on-metal movement of the piston.
Oil-Less Air Compressors.
The piston chamber of such air compressors is pre-lubricated and equipped with a permanent lubrication coating.
Teflon is the usual choice for such coating. By creating a smooth frictionless surface, it acts as a shield for the piston parts while working.
This coating tends to degrade slowly over time (essentially a self-lubricating design that will last for thousands of hours).
Speaking of pre-lubricated parts, there’s a sealed gearbox whose coating protects the moving parts of the compressor.
Note: Occasionally such oil less compressors tend to work at a bit decreased RPM, just so they could lower the possibility of overheating.
Oil Based Air Compressor.
I am sure you possess a rough idea as to what it means, well here oiling is required regularly.
As for the types of lubrication, there are a few which are employed quite often.
Commonly used in industrial compressors as well as in rotary ones, due to the high-pressure oil is forced through the chambers, courtesy of the oil pump.
This moving stream of oil (similar to how your car lubrication works) is more efficient in preventing the piston head from getting hot while working.
This system is the most common one. It makes use of an Oil Dipper which is present on the piston’s connecting rod.
From there it reaches inside the oil pump and sprinkles oil across the bearings including the piston chamber upon each revolution.
Life Expectancy Comparison.
First, let’s talk about oil free compressors.
In the real world, there’s always a catch. So, despite being so convenient with lubrication, these compressors are short-lived compared with the lubricated ones.
Oil less compressor is as good as the Teflon coating. Once it’s gone the compressor loses its efficiency so most people just get rid of it and buy a new one.
Typically, these compressors run smoothly for at least 18 months (that’s about 2000 hours).
Based on a common census, the most prevalent reason behind the failure of oil free compressors is-
“The formation of indents and leaks in the cylinder wall alongside piston, which decreases the air buildup”.
So, basically the compressor would have done twice the work to compress the same quantity of air.
This extended period of operation directly increases heat production which in turn accelerates the degradation process of pre-lubrication coating.
At this point, one or two things happen, either it loses its ability to turn off or gets seized in an overheated state.
Now you might be wondering, why do people buy these compressors at all?
Here’s the thing, shorter lifespan means you can have a relatively cheap air compressor. Which makes it easy for small scale manufacturers to mass-produce them.
After all the demand for a lightweight, cheap and a sturdy air compressor is always there.
Last but not the least, oil free compressors are equipped with universal motor rather than induction motors. The former is lightweight but is short-lived compared with the latter.
Don’t consider this aspect as a drawback because a universal motor certainly outlasts the piston.
Now let’s look at oil compressors.
An oiled air compressor has a much higher life expectancy. They can work effortlessly for at least a decade (more than 15’000 hours). Which is almost 7 times more than its counterpart.
One of the underrated advantages of an oil compressor is the use of cast iron as a piston head.
These piston heads are far more durable. As a result, show higher resistance towards internal scratches making it the prime reason behind the longevity and robustness of oiled compressors.
Having said that, a portable model of these compressors tends to be slightly heavier, which is a disadvantage.
Taking regular breaks and avoiding extended run-time are the best ways to maintain and safeguard the warranty of your compressor.
Let’s Compare The Noise Level.
Noise difference is the most significant difference of all.
Oil less compressors are extremely loud.
So loud that many people who use these compressors tend to use a long hose. So that they can keep the compressors away from their place of work.
In contrast, oiled ones run very smoothly, courtesy of the added lubrication.
In other words, you can actually have a chat with your pal while standing next to an oiled compressor.
In case you are compelled to have oil less compressor, then it is recommended that you buy a compressor intake muffler.
It’s a post-market unique filter that is crafted specifically to minimize the noise of your compressor.
The core function of both compressors is same, that is to create compressed air.
But, the consequential difference between them boils down to the quantity of air which they can compress. Most importantly what kinds of equipment will you be using with them.
Oil free compressors are notably lighter than the oil lubricated ones.
Thus making them ideal for domestic and small scale use. Where portability of compressor is needed, and the requirement of compressed air is less.
For instance, medical air supplies, tire inflation, jackhammering, etc.
On the other hand, an oiled air compressor is apt for fast-paced heavy industrial and construction work. As it can run for an extended period compressing as much air as needed.
The bottom line is, if you are looking for a compressor for a long haul then oiled one is the right choice. If not then oil free it is.
Weather Advantages And Disadvantages.
Despite so many drawbacks and weaknesses of oil free compressors, there is one crucial advantage that it has over its oiled counterpart. That advantage being their resistance towards cold weather.
Things become dire when you have to work outside in freezing temperature. As the oiled one makes use of high viscosity oil which makes it difficult to start the compressor and build the required pressure.
There are options of using light viscose oil like the 30S (most sought out one), or the 20S (our recommendation).
Meanwhile, you won’t have to worry about any of these if you make use of oil free compressors. They work effortlessly, regardless of climatic conditions.
The Purity Of Air.
The air filter is restrictive on the intake in most of the job site models and the likes of it. As such compressor is prone to suck in dust particles and debris thus accelerating the demise of the unit.
If you wish to steer clear from any issues, then it is advised that you keep the compressor away from flying dust and debris. Please don’t forget to clean the filter as regularly as you can.
A filter similar to the one you find in the car is present in the oiled compressor. This large air intake filter can be removed and replaced with ease.
Any Potential Problem With Airlines?
If you think its oil then you are wrong, because the more glaring issue arises due to water, not because of oil.
Draining the compressor alone won’t be enough. You need to incorporate some other applications like sandblasting or painting as an external dryer source to eliminate extra water.
After all, the more the merrier.
As far as oil is concerned, even if it escapes it will be of a negligible quantity which is hardly recognizable.
Moreover, the oil that escapes gets accumulated in the tank which gets released with an excess of water at the end of the day.
How To Maintain An Air Compressor?
Besides draining the compressor every night after use, there isn’t any maintenance hassle with the oil less compressor. No doubt It is one of the attractive aspects of this design.
You won’t have to worry about any oil spill in case your compressor gets involved in any unfavorable incident.
Can’t say the same with regards to oil filled compressors, as they require a little more pampering.
Usually, the change of oil happens after 500 hours of work. At this point oil is drained and replaced with the new one.
Furthermore, you need to check the oil levels every day before beginning your work. It’s better to make this your habit, for your compressor’s sake.
For this precise reason, many workers/contractors opt for the oil less one as they are portable smaller units. Also they can’t afford to spare additional time for maintenance.
Having an oiled model doesn’t make much sense, unless it’s a huge 60-gallon heavy-duty industrial model.
The Secret For A Longer Lifespan.
Do Not Overheat The Compressor.
This shouldn’t come as a surprise, as every air compressor has its threshold known as duty cycles.
Almost every oil free design is restricted to a 25-50% duty cycle, which means it needs to take a break of 50-75 % of the time.
In layman terms that would mean that if the compressor ran for 2 minutes, it would require at least 6 minutes to cool down before it can get back to business.
Using them at a continued and a faster pace will bring their demise sooner rather than later.
With oiled units, you can expect more flexibility as they are built to withstand longer duty cycles of 50-100% without suffering any considerable damage.
Clean The Filters Or Change Them.
Those tiny seemingly harmless dust particles can cause considerable damage by scoring the walls of piston if they reach the piston chamber through the filter.
This leads to reduced power production, so change the air filter at least once in 6 months.
Drain The Compressors
You know how rust can wreak havoc. So the tank is in considerable danger of getting destroyed by rust. Therefore, it is of utmost importance that you drain the tank at the end of the day.
So that any water accumulated inside the tank doesn’t compromise the integrity of it.
It directly depends upon your usage, the more you use, the more frequently you have to change the oil.
Then again if you are using 500-hour oil, you only have to change the oil twice or thrice per year.
In any case, follow the user manual.
Last But Not Least, How To Choose One?
When it comes to an air compressor the process of selecting is rather simple. All you need for consideration is the type of work you will be doing with it.
Like for instance a homeowner, who occasionally uses the compressor to remodel the house, or a family who’s garage needs one.
Needless to say, the requirement is minimal, so here oil less compressor is best suited as it has a lower output ranging between 2-5 CFM (Cubic Feet per Minute).
On the other hand, a fast-paced construction team, a mechanic or an auto body painting technician has a requirement far greater than a homeowner.
Hence they need an oiled compressor. As it has a higher output of more than 5 CFM.
Top of that it also has that much needed heavy-duty resistance, another defining feature of an oiled compressor.
Some people would rather buy an oil less compressor and replace it every year than have an oiled one. Due to the latter’s demand for regular maintenance.
In any case, the choice is yours, keep in mind that brand is important for better customer service and spare parts.