Types of Air Compressors
Air compressors come in all shapes and sizes, with a variety of different features. Here is a breakdown of the three most common types of air compressors and their key benefits.
The piston compressor is the oldest and most popular type of air compressor. It has been used for centuries to power tools and machinery. A piston compressor uses a reciprocating piston to pressurize air and send it into a storage tank. The biggest benefit of this type of compressor is its low cost.
The rotary screw compressor is a newer design that has become increasingly popular in recent years. It uses two helical screws to compress air, which results in less noise and vibration than piston compressors. This type of compressor also tends to be more efficient than piston compressors, and can achieve higher pressures.
How Loud Are Air Compressors?
Air compressors come in a variety of sizes, and each one has a different noise level. When shopping for an air compressor, it is important to know how loud the machine is so that you can choose the right one for your needs.
Sound levels above 85 dB can cause hearing loss over time. Therefore, it is important to consider the noise level when selecting an air compressor. Some manufacturers offer models with lower noise levels or sound enclosures to reduce the noise level emitted by the compressor.
Most air compressor manufacturers rate their machines on a decibel (dB) rating system from 0 to 140. This is measured in increments of ten. The higher the number, the louder the machine will be. The average noise level of an air compressor is around 85 dB, which is about the level where hearing protection is necessary. However, some compressors can produce noise levels as high as 110 dB.
A small portable compressor with 1 HP or fewer have noise levels of 80 to 90 decibels or more, while equivalent quieter compressor types have noise levels of 40 to 79 decibels.
However, it is important to note than decibel rating rise exponentially. So, an 80-dB compressor is twice as loud as a 70-dB model and four times louder than a 60-dB compressor, to give you a sense of the difference in levels.
Factors That Affect Noise Levels with Air Compressors
In order to best understand how to best mitigate the effects of this noise, it is important to first understand what factors affect air compressor noise levels. Some of these factors include the type of compressor, the size of the compressor, and the speed at which the compressor is running.
How does the type of compressor affect the level of noise it produces?
The two most common types of air compressors are the rotary screw compressor and the reciprocating compressor. The reciprocating type are more likely to be thought of as a loud air compressor, whereas rotary screw compressors are quieter – but why?
One reason for the noise difference is that reciprocating air compressors have more moving parts than rotary screw air compressors. This means there is more opportunity for things to go wrong and create noise. The moving parts of a reciprocating compressor are more exposed to the environment and generate more noise, and in addition, the pistons in reciprocating air compressors move up and down faster than the screws in rotary screw compressors, which creates more turbulence and noise. Finally, reciprocating air compressors tend to be less efficient than rotary screw compressors, and this also contributes to their noisier operation.
A rotary screw compressor has two helical screws that move air in opposite directions. This design keeps the moving parts enclosed and therefore generates less noise.
For more information on this, please see our 7000 word guide on air compressors and their types.
Oiled vs Oilfree
Many people are put off oil-free compressors due to their reputation for being noisier than oiled.
However, despite the fact that this is true for entry-level reciprocating air compressors at the very least, contrary to common assumption, there exist air compressors that are both very silent and oil-free. More and more manufacturers are creating new technologies for the medical, dentistry, and food sectors, which need the use of air compressors that are clean, silent, and free of oil.
Compressors with a dual-piston architecture include rotary screw, scroll, and reciprocating pumps, to name a few examples of these devices.
For more information on this, please see our guide Oiled vs oil-free air compressors.
How does the size of air compressor affect the level of noise it produces?
The level of noise a compressor produces is largely determined by its size. Larger compressors tend to be louder than smaller ones. This is because the larger the compressor, the more air it can move, and the faster that air moves, the more noise it creates.
Ultimately, how much noise a compressor makes depends on its size and how it’s configured. However, with careful design and installation, it’s possible to keep the noise level down even with a large compressor.
For more info on air compressor sizes, see our guide What size air compressor do I need?
How does the speed an compressor is running at affect the level of noise it makes?
The level of noise an air compressor makes is affected by the speed at which it is running. The faster the compressor runs, the noisier it will be. This is because the faster the compressor runs, the more air it moves, and the more air that moves, the louder it will be.
There are however plenty of ways to make an air compressor quiet.
How can vibration affect the level of noise it makes?
The vibration of the whole machine is the first and most fundamental reason for the increased noise from an air compressor. Even if it isn’t the most important aspect, generating noise is still a significant one. An air compressor‘s vibration is mostly determined by the fitting and type of compressor. There’s a strong probability that if you put the air compressor together incorrectly, it’ll start vibrating a lot. Additionally, parts can become loose over time, so it is good to check and tighten all bolts, screws and connections every so often.
Even though you constructed and installed the air compressor correctly, it might still generate a lot of noise due to specific sections of the machine. The vibration level rises if any portion of the machine is not correctly connected to the compressor.
How can where it is placed affect the level of noise it makes?
The noise produced by an air compressor is highly dependent on the location in which it is installed. If you leave the machine on a hard surface, for example, it will most likely create more noise throughout the run time.
In addition, if the surface is uneven, the air compressor will vibrate back and forth on the various levels it is sat on, so ensure that the compressor is placed on a level surface.
Reducing Noise from Air Compressors
If you feel like you have a noisy air compressor, the first thing to do is to make sure that the compressor is running correctly. If the compressor isn’t running at all, or if it is running but blowing air out of the hose and not into it, you may have a bad compressor. If the compressor is blowing air into the hose, but not out of it, you may have a bad hose. If the compressor is running and blowing air out of the hose and into it, you probably have a bad pressure switch.
But there are a number of ways to reduce the noise a compressor makes. One is to use an enclosure around the compressor to help deflect the sound. Another is to use mufflers on the exhaust pipe to dampen the noise. This will help to muffle the sound and reduce the amount of noise that is emitted into the surrounding environment.
Many of the tips below are low cost, whereas some will set you back a whole lot of dollars. However, I found a great video detailing some of the free ways to make an air compressor quieter. Credit to Bill Kennedy of The AIR Space:
Modify the air compressor itself
Add an intake silencer or muffler
The purchasing of an air compressor intake silencer is a less complicated solution for reducing the noise produced by your air compressor. Sometimes referred to as an air intake muffler, these little components are very effective in reducing air intake noise.
The silencers and filters that are available are designed to be installed directly into your vehicle’s air intake system. They function by drawing air through noise-dampening materials, which help to reduce part of the noise generated when the air is drawn into the compressor and into the machine.
Make sure that your air compressor muffler is compatible with your compressor before making a decision on which one to choose. Filter models and screw thread sizes are also included in this section. Whatever you do, avoid using a filter that is smaller than the one advised for your compressors, since this might cause harm to the compressor.
Extend the air intake
The air intake is an extremely important component of the air compressor. This is the point at which the air enters the unit. If you choose, you may relocate the intake to a location where the noise will not be as distracting to your surroundings.
Some air compressor owners have experimented with storing their machines in garden sheds, basements, or garages. However, the difficulty with the basement or garage is that these spaces are still physically connected to your home. However, even though the air compressor will be quieter than if it were located in close proximity to you, you would undoubtedly be able to hear it in the basement or in the garage.
The reason some individuals have chosen to transfer the input outside is because of the weather. When you have a large open space like a backyard or a side yard, the compressor generates less noise. It would also be farther away from your home, which would mean you would hear even less noise from your air compressor as well.
You can do this task yourself if you have a bracket and a rubber hose. In order to begin, take your rubber garden hose and insert it into the air intake opening. Don’t try to shove it into the intake since you can shatter it. Using a bracket that is set freely but securely, the hose will remain in place while the air compressor travels and functions.
If at all feasible, the other end of your hose should be buried a few inches beyond the surface of the earth. Use grommets or brackets to secure the hose’s other end precisely where you want it. The tighter the hose is secured, the less noise the whole arrangement should generate, in theory.
Use a rubber mat to absorb vibration
Vibrations are another significant contribution to the noise produced by air compressors. It is possible for the vibrations created by movement of the pistons or rotors to transmit through the floor to other portions of the facility, which implies that the noise may also transfer. It is recommended to lay a rubber mat beneath the compressor in order to absorb vibrations and prevent them from being transmitted through the floor. Additionally, cork or plastic have excellent shock-absorbing characteristics.
Use rubber grommets on the motor
As an alternative to using a complete rubber mat on the air compressor installation, you may utilise rubber grommets on the air compressor mount instead. Similar to the mat, the rubber grommet or foot acts in a similar manner, collecting noise-producing vibrations and preventing them from propagating through the floor. For this project, it’s better to have grommets made of rubber. These should be fitted so they can go over your air compressor’s motor.
Rubber grommets are a basic tool and are thus inexpensive. You can find a set of 200 pieces for less than $12 on Amazon or ebay.
Maintain your compressor properly
Tighten up loose components
Though unusual, loose parts and components of an air compressor may be a substantial source of noise in certain situations, especially when the compressor is subjected to vibrations.
There are several screws and nuts strewn throughout the compressor, and as a consequence of the constant use, they are getting more loose.
You must thus do regular maintenance on your compressor in order to ensure that it is not the source of the noise. If they are, though, you will need to either tighten them yourself or get a professional to do it on your behalf.
Lubricate the joints & bearings
The air compressor, like any other piece of equipment, is composed of metal elements that are always in motion. If the equipment does not get frequent and enough lubrication at the joints, these motions might cause wear and tear. Check the oil level in oil-flooded compressors (which may be rotary screw, rotary vane, or piston-style) several times a week to ensure that it is not running low, and replace the oil at least once a year or more frequently, depending on your working periods and circumstances, to ensure that it is not running low.
It is also necessary to oil the bearings in your air compressor motor, which is something you should do. A properly lubricated compressor will operate for a longer period of time and provide better sound quality.
The metal pieces will rust and deteriorate, and an irritating sound will be produced as a result. If the compressor is not properly examined, it will have to work twice as hard to keep up with demand, which will result in the compressor being damaged. You must have the proper lubricant on hand to apply to the joints on a frequent basis in order to avoid needless noise and damage.
When lubricating a smaller air compressor, proceed with care. Excessive lubricant applied to the bearing parts of a very small air compressor can actually raise the working temperature of the compressor. It’s critical to figure out how much oil your machine requires, or else you risk causing a churning effect that stops air compressors from performing at their peak.
Clean all the filters
The filters in your compressor could be the source of the noise. As air is taken into the compressor, the air filters work is to sift through to remove any dirt present that may damage the compressor.
Nonetheless, if you do not check the filters regularly, dirt can accumulate and clog the filters resulting in unbearable noise. When the air compressor filters are clogged, the machine will struggle to operate. Air will not quickly get through the filters, and the dirt particles inside the compressor will be all over.
Change intake filters when they appear visibly dirty or worn. Inline filters should be changed at least once a year or after 8,000 hours of operations. You can monitor pressure drop (the difference in pressure before and after the filter) to determine when filters are loaded.
Get a pro to go through your compressor
You may be able to extend the life of your air compressor by many years if you perform routine maintenance. While some of the more straightforward maintenance activities, like as lubricating and filtering, may be completed by the ordinary homeowner, there are other jobs that are better left to the hands of a qualified service technician. Contact a local service shop once or twice a year to have the components inspected and the vehicle’s performance evaluated. Every now and then, compressor components such as belts, gaskets, and valve plates must be changed, so check to see whether it is time to replace them. Indications that a compressor is in need of repair include increased noise levels compared to normal operation.
Use sound deadening
Build a soundproofed box around it
It goes without saying that boxing up your air compressor will make it seem quieter to you. Your air compressor could be housed in a soundproof enclosure, which you would construct. By using soundproofing materials on the walls, such as acoustic foam, you may almost eliminate the possibility of hearing the air compressor.
It will be expensive to go down this road since you will be constructing a modest structure from the ground up. You’d also need to make sure that the area is large enough to accommodate the compressor and that it has sufficient ventilation. A failure to do so will result in the air compressor overheating, causing a fire or even an explosion as it heats up.
Soundproof the walls of the room it is in
Prior to this, I advised that rubber mats be placed between the compressor and the hard surface its standing on. You may do the same thing with the walls that surround the compressor as well. You will hear more noise if you set the compressor near a wall since the sound will be echoed and reverberated. In addition, if you place the compressor in a tight space, this will also cause more noise.
It is not necessary to cover every inch of the wall in the room though – you only need to place the padding to the adjacent wall of the compressor in order to prevent sound from reverberating.
Cover the compressor with a sound blanket
It is possible to cover the compressor if you are unable to connect the sound-absorbing material to the wall or build a soundproof enclosure for the compressor. You will need to utilise a sound blanket for this purpose. The sound blanket should be used to completely around the compressor. This will act as a soundproof box, keeping the sounds contained.
Work in a separate room
This is a pretty basic but effective one! But when you are close to the air compressor, the noise is obviously louder. So a completely cost free improvement is simply to try and work in a separate room to the compressor itself – use longer pipes for your tools, to enable you to work further away from the machine creating the racket!
Wear earplugs or defenders
Earplugs should always be used if you are running an air compressor or any other loud equipment — such as chain saws, grinders, drills and so on. This will safeguard your hearing. Even if you believe that your ears are strong enough to withstand the loudness, ears are similar to eyes in that they are susceptible to damage. Hearing deteriorates in much the same manner as vision does throughout the course of a person’s life. Just like with vision, repeated exposure to harmful noise may cause the ear drum to become weaker faster. For this reason, just as you should not read from a computer screen in a dark room or strain to see tiny print from a distance, you should avoid exposing your ears to the magnified sounds produced by noisy equipment as much as possible.
Earplugs may be purchased at a local hardware shop or from Amazon super-cheaply. Keep them in your pocket at all times when you enter your work area, and place them in your ears shortly before turning on the air compressor to prevent hearing loss. I myself have lost some of my hearing and suffer from mild tinnitus due to not wearing ear protection in my youth, and I can tell you it’s not fun. So protect your ears people!
Buy a quieter air compressor!
Another duh, of course kind of point, bit this tip is for those who are looking for a compressor but are worried about the noise it will generate. The good news is there are quieter compression options out there. No compressor is completely silent, though – you should remember that you’ll always have to deal with some level of noise when using a compressor. However, most air compressor manufacturers give the Db reading for their products, so look for one under 85Db and you should not require earplugs – that’s pretty much my definition of a quiet compressor!