How to Pick a Compressor for Vehicle Washing

Cleaning your vehicles after a rough day out is necessary to not only make them look good but also to maintain their optimal running condition. But simply washing your vehicles with a pail of water and basic brush may not be enough to remove dirt.

In this article, we help you choose the right compressor to aid you in washing your vehicles, so no extra costs will come to haunt you when you least expect it.

1.  Air Compressor Usage

Ask yourself what you’ll be using the air compressors for. If you need them to basically fill up your tires with adequate air, which isn’t always necessary, you only need one that’s portable. If you have an auto detailing business and require pressure washing, you need big air compressors that can boost water pressure to effectively remove stubborn dirt.

If you’re going to do things occasionally or daily, your air compressors are going to use a lot of air and electricity. The truth is most residential garages are only meant to sustain 120-volt outlets but there are instances when you may have to use 240-volt outlets for running washers.

Because of this, you should ask the help of your trusted electrician to make important wire adjustments on your outlets that are suitable for particular tasks. It all boils down to the more power, necessity and efficiency, the bigger air compressors you need to achieve desired results.

2.  Air Compressor Noise Level

Oiled air compressors tend to have very minimal noise but you can’t expect the same thing on their counterpart. Generally, air compressors that don’t require oil can be very disturbing because they can normally reach to 100 decibels which is characterized by a passing vehicle.

If you own a car wash that operates in the morning within your area surrounded by similar businesses, this may be a usual scenario but if you’re only planning on doing midnight clean-ups because it’s weekend, there’s a chance you’ll give your neighbors a difficult time sleeping. To give you an idea which sounds are acceptable and which aren’t, check out our sound table here.

Make sure you put your air compressors in a certain area of your garage where their sound will be reduced but is large enough to provide them with proper ventilation.

3.  Air Compressor Design

Air compressors come in different forms. There are those you can conveniently carry around while others are slightly bulky. Wheeled or trolley type air compressors are bigger than the typical pancake and hot dog compressors but are still considered portable because you can easily move them from one place to the next, as their wheels suggest.

On the other hand, there are air compressors that are really big in such a way they can’t be taken outside because they’re meant to stay in one place like in your garage or workshop. Examples of these are the single-stage and scroll compressors that can be used for pressure washing and sandblasting because they consume a huge amount of air.

Why shouldn’t they? Such air compressors have average air tanks of 60 gallons which means they’re made to withstand long and repetitive hours of usage. Basically, you can say these things are heavy-duty.

4.  Air Compressor Operation

Suppose you’ll want to use a random orbit pump sander for sandblasting. Its size is 15 CFM and you’ll be using it to smoothen the rough exterior parts of your 4WD. You can’t expect it to continuously run for a long period and will eventually stop. Therefore, you need large air compressors to fill it up so your work won’t be interrupted.

The same thing goes when you’re usually pressure washing your vehicles. If you’ll be using a spray gun that’s only 25 CFM, you have to wait for the ample time when large air compressors power it up.

Air compressors’ PSI should also be taken into consideration because it affects air pressure. Even if your air compressors are capable of giving off air at more than 1,000 PSI but your spray guns or nozzles are limited to only 70 PSI, air pressure will obviously be reduced; hence, there’s little thing that can be said about the spray guns’ usefulness.

5.  Air Compressor Fitting Sizes

Another thing to prevent from getting away the eye of scrutiny is the fitting size. Imagine you’ll be using a hose in washing your vehicles and you’ll be inserting a fitting or coupler into it.

It’s possible to have a thread size with a wide diameter of 20” but its mouthpiece is just 10.” Since the fitting or coupler’s mouthpiece is half the size of its thread size, expect that the amount of air delivered into your washing tool will be reduced.

Another thing to note is the longer the hose and the smaller the coupler, the less air you can feed into your washing tool. For example, your air compressors can produce 85 PSI of air. However, you’re using a 3/8’ hose and a very small fitting, there’s a chance your washing tool can only acquire and give off air that’s 65 PSI.

Since air compressor fitting sizes differ from manufacturers and designs, you only need to look at three important factors.

Coupler Style – There are 10 primary coupler styles to choose from but the common ones you’ll see are the 4 styles: A, P, L, M. Such styles have varying air flow capacities that are suitable for respective air tools. Too much air flow can damage the air tools but a very low one can cause them to malfunction.

Coupler Flow Size – Just to clarify, the flow size has nothing to do with the thread size. The thread size is the part that you attach to the hose but no matter how large it is, the coupler’s entire design determines how much air should come out of it. Supposed you have two M style couplers. Even if one’s thread size is 10” and the other is 15,” they’re still expected to produce air at 45 SCFM as long as their bodies are both 3/8.”

Connector Type – The female and male pipe connections are those you twist to put them on a hose. Hose barb connections are what you simply push into the hose.

More on this matter when you go to The Ultimate Guide to Fittings and Couplers for Air Tools.

6.  Air Compressor Specification

Air compressors have different specs based on their tank size and overall design. These specs give you an idea of how air compressors work under certain circumstances, up to what extent they function and what makes such function limited.

Pounds per Square Inch (PSI) indicates the strength or force exerted by the air compressors on a particular object.

Cubic Feet per Minute (CFM) tells the amount of air that air compressors can give.

Standard Cubic Feet per Minute (SCFM) is the amount of air that spray guns can consume depending on the existing atmospheric condition. Because of this, SCFM is always greater than CFM.

Other Tips for Buying an Air Compressor

Determining the main factors in choosing the right air compressors for your pressure washer is a vital step towards effectively using them. However, there are also other things you need to consider as they affect air compressor functionalities even in an indirect way.

Examine your spray tools – Your spray tools should be suitable for the different air compressor ratings (e.g. PSI, CFM and SCFM). This gives you an idea of the kind of air compressors you need to pair with them. For example, if your foam gun is rated at 35 CFM but you decided to get air compressors that are only capable of 15 CFM, the latter won’t make it because their pumps will be working overtime and will be damaged eventually.

Identify the air compressor tank size – As what it obviously suggests, tank size translates to air compressors’ storage capacity to accommodate a sufficient amount of air. For heavy-duty variants, tank sizes can range from 20 gallons to about 500 gallons. The larger the air compressors’ tanks are, the longer period it can sustain your foam gun until the air compressors require an air refill.

Search for air compressors with good average SCFM numbers – There are air compressors that are about 4.6 CFM at 335 PSI but there are those rated at 5.2 CFM for 90 PSI. Generally, the greater the air pressure, the lower the air flow generated and vise versa.

Check out Tips on Buying Your First Air Compressor for further details.


Picking an air compressor for washing your vehicle based on the following pointers helps you assess the exact air compressor style that you need. And by the time you have one, you’ll know how to use it without so many questions still popping up your head. Ever had a hard time figuring out the perfect air compressor? Share us your experience and what you did to fix it.