What Size Air Compressor for Painting? Pro Painters Guide

An air compressor can be used to run different pneumatic tools – a paint sprayer is one of them. Using a paint sprayer with an air compressor is more efficient and faster than other methods. 

However, to successfully run the tool, you need an air compressor that matches the needs of the sprayer. If you’re not an expert, this can be difficult to figure out. 

So, today, we will look at how to determine what size air compressor for painting you need based on a number of factors.

What is An Air Compressor?

An air compressor is a machine that “compresses” atmospheric air through the use of an electric motor or engine. And stores the compressed air in a cylinder or tank. 

The compressed air is then used for various purposes, such as painting a house, inflating a tire, or powering different pneumatic tools.

When it comes to spray painting, the air compressor is connected to a spray gun and nozzle, which uses the air supplied by the compressor to expel paint to the target surface. 

How Do Air Compressors Work?

An air compressor works by forcing air into a cylinder or tank and pressurizing it. 

To make this possible, the machine is equipped with a motor, which powers a piston to compress air and send it into a tank for storage. This causes pressure to build up in the tank to a certain point where the machine turns off. 

The stored compressed air can then be released through a valve and used as energy to power various tools, ranging from sprayers and nailers to sanders and impact wrenches. 

Painting with an air compressor is much more efficient and faster than other painting methods. But like other machines, it requires regular maintenance to keep it running smoothly.

What Size Air Compressor for Paint Sprayer?

Here are the factors to look at to determine the right compressor size for your project.

1. CFM

CFM (or cubic feet per minute) is the amount of air generated by a compressor at a specific pressure. It is the most important factor to consider when determining your air compressor size and efficiency. 

In general, CFM has a direct impact on size. Larger compressors have a higher CFM, while smaller compressors have a lesser CFM. 

To get the best results, you want to choose an air compressor that has a higher CFM than your sprayer. A higher CFM makes the painting process possible and ensures you get a uniform finish.

Most spray guns have a rating of 10 CFM or less. So you need a compressor that is capable of at least 12 CFM. Again, the idea is to choose a compressor that has a higher CFM than your spray gun. Otherwise, the gun won’t operate efficiently. 

2. Tank Size

The compressor tank is where the air is stored. The size of the tank also determines how big the unit is. More importantly, it can make a difference in the overall efficiency of the unit. 

A larger tank can hold more air. This means it can continuously supply air for longer periods before it needs to be refilled. This is particularly important when you’re working on an extensive project. 

On the other hand, if you’re using a smaller tank, there may be a need to stop it a few times in between your project.

Small air compressor tanks also cause variations in pressure and material flow, which can lead to uneven coats. 

Generally, it’s better to choose a compressor with a higher tank capacity to ensure consistent airflow and minimize disruptions in your work. It can be 10 gallons or even 60 depending on the size of your project. 

3. Horsepower

Horsepower (H.P.) is a measure of the power or amount of work a compressor can do. Higher horsepower means the compressor can deliver a higher volume of air and pressure.

For small paint jobs and DIY projects, a 1-3 H.P. will typically suffice. However, for more extensive projects such as painting cars or houses, you may need a compressor with up to 10 H.P.

While a higher H.P. compressor might be more versatile and operate more efficiently, it doesn’t necessarily mean it’s better for every tool. 

4. Air pressure

Another thing you want to look at when sizing a compressor is the PSI (pounds per square inch). PSI is a measure of the air pressure delivered by the compressor. 

A higher PSI translates to a higher volume of air in the tank, which means the compressor will be considerably larger.

In general, PSI is less important than CFM when sizing an air compressor. This is mainly because it has less impact on how well the paint medium is atomized, especially when you’re using an HVLP spray gun. 

It is a high CFM that ensures the gun pumps out very fine mist particles, which results in a smooth finish.

Generally, it’s recommended to choose a compressor with at least 15 PSI for minor touch-ups and other small jobs. Higher PSI is usually desired when painting a thicker liquid.

5. Style

Air compressors come in various styles. The more common ones for air sprayers are pontoon, pancake, and hot dog compressors. 

Pontoon compressors have a higher CFM than other types and deliver a longer run time. They are typically robust and less portable. 

In contrast, pancake compressors are lightweight and easier to move about but are not as powerful as pontoon compressors. 

The best compressor style for you depends on the specific needs of your project, whether it’s a small, large, or medium-sized project. 

What Size of Air Compressor for Painting Furniture?

To paint a small piece of furniture, such as a table or chair, you will need an air compressor with a tank size of at least 10 gallons. This is because you only need about 20 PSI for such projects, which is more than what you can get with a 10-gallon compressor. 

If you want something more powerful, you can opt for a compressor with 20-30 gallon capacity. 

But for most DIY painting projects that involve furniture, a 10-gallon compressor would usually be enough to run your air spray gun. Especially if you don’t have the money to afford a larger compressor.

What Size of Air Compressor for Painting Houses?

For a large project such as painting a house, a 10-gallon unit would not suffice. You will need a more powerful air compressor, something larger that can provide more pressure and runtime.

For such projects, we highly recommend a 60- or 80-gallon compressor. With this, you can paint a small/medium house with 3-5 rooms. 

For such compressors, a higher CFM is desirable, so aim for something with around 20 CFM and at least 40-50 PSI.

Depending on the size of the house or how many rooms are there, you may need to refill the tank a couple of times. Ideally, you would want to paint room-by-room, which makes it practically impossible to cover the entire house in one shot.

Of course, you want to properly prep the walls beforehand to obtain smooth and professional-looking results. 

What Size Air Compressor for Painting Cabinets

Cabinets and cars can be considered medium-sized projects. In this case, we would recommend a compressor with a 20 to 40-gallon tank, depending on your budget. 

For instance, if you have less than $1000, you will be able to purchase a good 20-30 gallon compressor. Usually, with a larger compressor, there’s lesser portability. But you will get more runtime.

Make sure any unit you choose has at least 12 CFM. Expectedly, this should exceed the CFM of your spray gun.

What Size Air Compressor for Painting a Truck?

When choosing an air compressor for your truck, ideally, you want something that will be running for as long as you need to paint the truck. 

In this case, a 60-gallon compressor will suffice. This should allow you to paint the entire truck with a single coat. You may need to refill the tank if you wish to apply several coats. 

If your budget allows it, you can also get an 80-gallon compressor to get more runtime. 

Advantages of Using a Paint Sprayer Air Compressor

Here are some of the benefits of using a paint sprayer with an air compressor:

• Easy to adjust: Most air compressors can be tailored to different spray guns. You can tweak the air pressure and CFM to suit the spray and painting medium.
• Less Westage: Compared to airless sprayers, spray guns that use compressors are generally more efficient. They use a smaller amount of paint and produce less overspray.
• Safe to use: Most air compressor sprayers are HVLP spray guns, which operate at lower pressure (e.g., 10PSI). Airless sprayers operate at a much higher pressure, sometimes up to 3000PSI or more, which ,makes them more difficult to control and not safe for beginners.
• Low noise: Air compressors are generally quieter than haydraulic units. They can be louder than turbines but not enough to cause much concern.

• Versatile: Once you have an air compressor, you can use it to run many pneumatic tools, not just a paint sprayer. 

Other Factors to Consider When Choosing an Air Compressor for Painting

1. Lubrication

Until now, air compressors used to be equipped with regular oil pumps and, as such, required regular lubrication. 

Nowadays, there are many oil-free models that are pre-lubricated. This means you don’t have to oil them regularly. 

In deciding which option to go for, you have to consider the price, power, and level of maintenance. 

Oil compressors tend to cost more but are harder to maintain as you have to oil them regularly. However, they are generally more powerful than their oil-free counterparts and tend to last longer. 

In contrast, oil-free pump compressors cost less and don’t require much maintenance. 

2. Noise

The noise produced by an air compressor is a big deal, especially if you’re working in a confined area. It’s best to use a compressor with a low noise level so it doesn’t disturb the people around you. 

Unfortunately, most soundless compressors are usually very pricey. But that does not mean you can’t find a modest unit that is less noisy. You just need to look around. 

The noise level is usually indicated in decibels. A lower number (of decibels) means the compressor is less noisy, while a higher number denotes more noise. 

Even with noisy compressors, it is still possible to reduce the noise by installing a few accessories. A good example is a sound damper-like fiberglass insulation. This helps to block the noise so it doesn’t spread out. An intake silencer filter can also reduce noise at the inlet holes of the compressor.  

3. Fuel

Another thing you need to consider when choosing an air compressor for your sprayer is the fuel. There are two main options you can choose from – gas and electricity. 

A small electric motor powers electric air compressors and are simpler to operate. They are less expensive, which makes them more suitable for DIY projects. 

Gas-powered units, on the other hand, are more suited for heavy-duty projects. They are more reliable and versatile but tend to be much louder than electric models. However, because of their exhaust systems, they should only be used outside to avoid polluting the room. 

4. Portability

You will agree that carrying a 10-gallon compressor is not the same as carrying one with an 80-gallon capacity. There’s a huge difference in the weight of both machines.

While an 80-gallon capacity unit will run your spray gun for longer periods, it’s quite heavy. This means it will have to remain in one location while in use. This limits your mobility since the compressor is stationed in one place.

If you want something you can frequently move around, then you would want a portable air compressor, something with a lower capacity. A 10-20 gallon tank compressor with wheels would be more convenient. 

Can I Spray Paint Without a Compressor?

Yes, you can, but you will need a sprayer that doesn’t run on a compressor. Paint sprayers are of two types – air sprayers and airless sprayers. 

Airless spray guns typically use electricity or high-pressure gas to expel paint onto the substrate. 

Air sprayers, on the other hand, require a compressor to effectively pump the material out. The compressor unit supplies compressed air, which is used to atomize the paint.

FAQs – What Size Air Compressor for Painting

Can I Spray Paint With a 3 Gallon Air Compressor?

No, we don’t recommend this. A 3-gallon compressor is a very small air volume and won’t be able to do any meaningful work. You may attempt using it for small painting jobs such as touch-ups or minor patch repairs, but that usually means refilling the tank very often. If you want to do any serious work, opt for something with at least 15 gallons.

Will a 6-gallon Air Compressor Run a Paint Gun?

A 6-gallon air compressor will probably run a paint gun, but you will have to refill it very frequently. So, we don’t recommend using it. Rather you should opt for a unit with higher air delivery. 

Is a 26 Gallon Air Compressor Good for Painting?

Yes, a 26-gallon air compressor can be very useful for painting a small car or room. Depending on the size of the room, you may need to refill it one or two times to paint all four walls. Besides the tank size, you should also look at the CFM and PSI rating to ensure it meets your gun requirements.

How Much CFM Do I Need for Spray Painting?

Your CFM requirement depends on the particular sprayer you’re using. Some sprayers require a CFM of 12 or lower to function optimally, while some may require up to 20 CFM or even higher. In general, smaller guns typically have a lower CFM rating than bigger ones. You want to choose a compressor that exceeds the CFM of your spray gun.  

How Much PSI Does a Paint Sprayer Need?

In order to get a paint gun working properly, a compressor unit needs to output at least 25-30 PSI for a small surface. However, for larger surfaces, such as a horse, you will need something that gets at least 35-40 PSI. Using a low PSI means the gun will not work correctly, and that can ruin the paint job.

What is the Best air Pressure for Spray Painting?

This depends on the specific spray gun you’re using and your project requirements. Some sprayers come with a pressure chart that includes what the manufacturer recommends for different projects. In general, for most DIY jobs, you will need around 25 to 30 PSI. This can increase to 40 PSI or even more whenever there’s a need for higher atomization. 

Content Summary – What Size Air Compressor for Painting

To conclude, choosing a suitable air compressor size will ensure you enjoy a longer run time and achieve a professional finish. 

Consider things like the CFM, duty cycle, air pressure, and tank size of the compressor unit. Ideally, you want to choose something that matches the requirements of your paint spray gun. 

In general, the best-sized compressor is one that exceeds the pressure and air delivery requirements of your sprayer. For instance, if you have a spray gun that requires 5 CFM at 10 PSI pressure, then your chosen compressor should output at least 10 CFM and 20 PSI. 

Let us know if you have any more questions. Until then, happy spraying!