
Air Compressor Basics
Air compressors are used for many applications including inflating tires, power tools, airbrushing, and more. An air compressor is a device that compresses air and stores it in a tank for future use.
When selecting an air compressor, it is important to consider how long it will take for the compressor to fill the tank.
Air compressors are available in a variety of styles and configurations, making it easy to find one that meets your needs. Generally speaking, there are two main types of air compressors: reciprocating and rotary screws.
Most portable reciprocating models typically fill in less than 5 minutes, while larger stationary models will take longer than 10 minutes to fill the tank of compressed air. Rotary screw models tend to take longer to fill but have higher cfm ratings which can make them ideal for larger jobs.
Factors that affect the filling time
When it comes to air compressors, knowing the factors that affect filling time is key in finding the machine that’s best for your needs. Filling time is greatly influenced by a few key factors: tank size, cubic feet per minute (CFM), and pressure.
Tank size often referred to as capacity, is measured in gallons. Generally speaking, larger tanks are going to take longer to fill than smaller tanks because they need more air. Tank sizes can vary from 1 gallon up to 80 gallons and even higher.
CFM, or cubic feet per minute, is a measure of how much air the compressor can flow into a tank within an hour. The higher the CFM rating, the faster your compressor will fill a given tank size. This is particularly important when trying to fill large tanks quickly and when running multiple tools with compressed air at once.
Pressure, measured in pounds per square inch or PSI refers to how much pressure is being put on the compressed air as it enters into and exits a tank through an output port. Low pressure means less force; higher pressure means more force but also slower filling times due to its resistance against airflow into the tank.
Air Compressor Filling Time

The time it takes for an air compressor to fill will greatly depend on the size of the tank and the type of compressor used. Different compressors will have different methodologies of filling, ranging from a basic one-stage compressor to a multi-stage system. This can drastically reduce or increase the amount of time it takes for your compressor to fill. Let’s take a look at the factors that determine how long a compressor takes to fill.
Single-stage compressors
These single-stage air compressors provide the following advantages:
- Oil-lubricated units use splash lubrication where oil bathes most of its internal parts, providing better durability and longer life
- A simpler design makes for easier maintenance
- The compact size makes installation easier
- Consumes up to 15 percent less energy when compared to two-stage models
Two-stage compressors
Two-stage compressors can fill a tank faster than single-stage units, and they’re ideal for applications that require high pressures. In most cases, two-stage compressors will fill a tank to about 175 psi in about 1/3 of the time it takes for a single-stage compressor to reach its final pressure.
A typical two-stage system uses an oil-lubricated crankcase and two separate circular pistons — one large diameter, low compression cylinder that feeds a small high compression cylinder, both of which may be operated simultaneously.
Under full load conditions, cylindrical tanks on two-stage units are typically filled in 70 percent or less of the time it takes to fill comparable “single shot” or single-stage models; making them great for machines and other automated systems that will run continuously for extended periods of time.
Multi-stage compressors
Multi-stage compressors are more complex than single-stage compressors but offer several advantages to users. They are equipped with multiple cylinders that can be used in sequence to provide higher levels of pressure and flow rate. The cylinders are activated one at a time until the desired pressure is reached, making for a more efficient process and faster filling time.
Since multi-stage compressors don’t need to be run continuously in order to reach a high-pressure level (or large air volume), they are often preferred by customers in need of lighter, portable solutions that require less energy consumption and maintenance.
When it comes to filling your compressed air system with one of these types of compressors, then it really depends on the size of the cylinder as well as the ambient pour temperature.
Calculating Filling Time

Calculating how long it takes for an air compressor to fill can be critical to understanding the performance of the machine. It can help you determine the capacity of the compressor, how fast it is filling it, or if there is a mechanical problem. By understanding how the system works, you can improve the efficiency of the compressor and save yourself time and money. Let’s take a look at how this calculation works.
Tank capacity
The capacity of the tank, or the volume of air it can hold, is one of the most important aspects when determining the filling time for an air compressor. Smaller units with a tank capacity in the range of 5-15 gallons may only require under a minute to fill, while larger tanks closer to 30 gallons may take several minutes or more.
It’s important to note that the amount of air available might not be sufficient for continuous use – provide some resting time before using it again. This is due to factors such as cooling systems being unable to keep up with demand, motors running hot and needing time to cool down, and energy-saving features.
Finally, other elements affecting your overall compressor filling time include operating temperature, motor size, and AC voltage rating used in production. Taking these into consideration along with your measurements will give you a better idea of how long it will take for your compressor system to fill its tank completely.
Compressor power
When calculating how long it will take for an air compressor to fill a particular tank, the power of the unit being used must be taken into consideration. The power of a compressor is measured and defined in horsepower (hp). The more powerful the unit, the faster it can fill a tank with air.
In general, 1 hp is required to move 4.2 cfm of air at normal atmospheric pressure, while 1 hp will move 5 cfm at atmospheric pressure above normal.
you should consider these variables:
- The size of the tank being filled the amount of time needed to produce an adequate amount of compressed air
- The power output achieved by the motor/compressor
- Atmospheric conditions present in your region
To accurately calculate the filling time for your compressor, you should review its power rating and then use this figure to estimate how long it will take for the device to compress enough air for filling purposes.
Ambient temperature
Ambient temperature has a significant influence on the performance of air delivery systems. Increasing the temperature increases the pressure and decreasing the temperature reduces the pressure.
This means that a fixed-capacity of air delivery system is able to deliver more compressed air when the ambient temperature is higher and vice versa. As a result, a reasonable estimation of filling time can be made given knowledge of ambient temperature and tank capacities.
Troubleshooting

If you are having trouble with your air compressor taking too long to fill, there are several possible causes. The most common causes are if the air compressor is set at too low of a pressure, if the air compressor is too small for the size of the tank it is filling, or if there is an obstruction in the airline. Troubleshooting these issues can be relatively straightforward and can often be accomplished with just a few steps.
Check the air filter
Checking the air filter on your air compressor is an important part of routine maintenance and can prevent a lot of common problems. The filter is there to protect the internal components from dangerous levels of dust and dirt that can interfere with normal operation. Make sure that the filter is free from debris, and it should be replaced every few months or after any cleaning to ensure peak performance.
If the air filter has been neglected for too long, it could be blocked by dust or debris, causing your air compressor to struggle while trying to fill up its tanks. To troubleshoot this issue, change out the existing filter with a new one. If this does not solve the problem, inspect the airflow throughout all parts of your compressor and look for other sources of blockage like valves or lines that may need to be cleared. If necessary, contact a professional technician.
Check the air pressure switch
The air pressure switch senses the pressure of the air supply to the unit when the motor is running. It also signals the motor to turn off if there is an inadequate or excessive supply of air. If you suspect that your machine is not functioning properly, it’s important to check the pressure switch first.
There are several reasons why your unit may be having difficulty with its air supply:
- The fan or blower might be clogged with dust or debris, which causes backpressure in the system and prevents proper airflow.
- The pressure switch may need to be adjusted more accurately for your particular application.
- The belt used on some machines can stretch over time, causing reduced efficiency and resulting in decreased airflow as well.
- issues such as incorrect wiring, damaged components, worn out components, and blocked filters can cause improper operation of the system as well.
It is important to remember that different parts of a system must work together in order for it to achieve peak performance.
Check the pressure regulator
The pressure regulator is the device that controls the amount of air pressure in the tank. It’s important to check it regularly as part of your routine maintenance and troubleshooting process. It should be set at a level below the maximum available pressure for your compressor and should be checked when starting up or carrying out any repairs to ensure that it’s working correctly.
If the pressure regulator is not set correctly, or if it has been tampered with or damaged, this can cause an incorrect flow of air, which can lead to long filling times. To check your pressure regulator, you’ll need an accurate gauge designed for this purpose. Check the rating of your compressor and confirm that the gauge you are using is compatible with its output rating.
Once you have a suitable gauge connected to your compressor, use it to measure the air pressure output at different stages in operation: when cold (before turning on), at idle/resting state, and while running under load. Compare these readings against both manufacturer’s recommendations and any applicable local regulations.
If you find significant discrepancies that cannot be attributed to environmental factors such as altitude or temperature, then further investigation will be required — which might include dismantling and checking for external blockages or replacing components such as faulty valves and gaskets.
Maintenance

Maintenance of an air compressor is a key factor in its performance and longevity. Air compressors require regular servicing in order to stay functioning optimally. This includes regular oil changes, checking belts and hoses, and checking the pressure gauge. Understanding how to properly maintain an air compressor can also help in determining how long it takes to fill.
Regularly inspect the air filter
Regularly inspecting and cleaning the air filter of your air compressor can be important for a few reasons. First, not changing the filter as needed can reduce the power of your air compressor because it will take longer for it to fill. This is due to the fact that when the filter gets clogged.
It reduces the airflow and limits how fast the tank can fill with compressed air. Second, there’s also a risk of damaging components in your air compressor if dirt and debris enter it. Finally, a dirty or clogged filter can reduce efficiency by putting more strain on your motor meaning you’ll need to run your compressor longer to fill completely.
To clean and inspect your air filter regularly:
- Unscrew it from its housing
- Gently remove any debris from inside or out
- Check for any signs of wear or damage
- Clean with warm soapy water if necessary
- Dry thoroughly before replacing
- Pat yourself on the back! Check the oil levels
Checking the oil levels in an air compressor should always be part of a regular maintenance routine. Oil helps to lubricate the internal parts of the compressor and keeps it running smoothly.
Before checking the oil level, ensure that all necessary safety precautions have been taken, such as turning off the power and ensuring that all pressure gauges have been released. After ensuring that it is safe to proceed, open up any inspection panels located on your air compressor and take a look at your dipstick or sight glass.
The oil level should be between two marks or halves indicated on your dipstick/sight glass. If it’s below these marks, you will need to add more oil in accordance with what is recommended by your manufacturer’s instructions. Once completed, start up your system again to check for any minor problems due to excessive wear and tear from lack of lubrication or air leaks from aged components such as seals, gaskets, valves, etc.
Change the oil regularly
Regular maintenance is an important factor when it comes to air compressor longevity, and it’s vital to ensure the health of your machine for a long time! Changing the oil in your air compressor should be done every three months or 600 hours.
Many machines have an onboard oil reservoir that should be emptied and the appropriate type of oil refilled. If the mechanism doesn’t include an easily accessible reservoir make sure you follow directions on how to properly empty, clean, and refill your compressor. Regular oil changes are essential in helping prevent damage to internal parts, as well as keeping running costs low.