How Does Car Air Conditioning Work?

hand checking car air conditioning

Chances are that if you live in Texas, you are very familiar with air conditioning… but have you ever stopped to wonder, “How does car air conditioning work?” The fact is that a car’s air conditioning system doesn’t operate in a way that many people would find intuitive. For starters, your car isn’t exactly “making” cold air— it’s removing hot air!

Sound confusing? Don’t worry, we’ve got your back. Here, you can learn how to answer the question, “How does car air conditioning work?” While knowing this information might not make you a star at cocktail parties (unless it’s a cocktail party for mechanics…) it can help you troubleshoot A/C issues and make informed decisions about your car’s maintenance.  

So, how does car air conditioning work?

To describe how car air conditioning works in the most basic of terms, you would say that the car A/C system uses the condensing and evaporating of refrigerant to absorb heat from the air inside your car, reducing the temperature.  Now, let’s break that down a little.  

Compressor:  Compresses the gaseous refrigerant

The A/C system has a high-pressure side and a low-pressure side. On the high-pressure side, a compressor uses pistons to compress the refrigerant gas (frequently called Freon).  The compressor is driven by the engine with a belt. The act of compression makes the high-pressure side of the loop very hot.

Condenser: Refrigerant cools and becomes a liquid

Next, the compressed, hot, refrigerant then travels to the condenser. The condenser is a set of coils that looks a bit like a radiator. As air passes over these coils, it takes away the heat of the refrigerant, which allows it to condense into a liquid. 

Receiver-Dryer: Uses desiccants to remove water

The liquid refrigerant now moves through the receiver dryer. The receiver-dryer contains desiccant—those same little granules that you find in white bags in bags of beef jerky or shoeboxes—which attract moisture. Why? Because it’s important that there is no H2O permitted to move on to the next step; if water gets through the receiver-dryer, then it can form ice crystals, which will reduce the efficiency of your A/C system.

Expansion valve or orifice tube: Allows the high-pressure freon to convert back to a gas

After passing through the condenser, the refrigerant then moves through an expansion valve or an orifice tube (depending on your vehicle). Both the valve and tube essentially serve the same function: The rapid expansion of the liquid freon converts the freon back to a gas. In this process, the gas becomes extremely cold.

Evaporator:  Warm air from inside the vehicle passes over the refrigerant

Here is where everything culminates. The refrigerant in the Evaporator is very cold and when a fan blows air over it (and into the car cabin) you feel nice, cool air coming out of the vents. Meanwhile, the refrigerant has absorbed heat from the air inside the vehicle. The gas then carries this heat back to the compressor, where the cycle begins again.

Why is my car air conditioner not blowing cold air?

Let’s say that one day you hop in the car and crank the A/C only to be blasted by hot air for your entire drive. It’s time to do a little car air conditioning system troubleshooting. Typically, when your A/C stops blowing cold air, it means that either you need to top off the refrigerant or an electrical or mechanical part of the A/C system has failed. 

No matter the cause, you’ll likely want to visit a trusted mechanic to have the problem diagnosed and serviced. If you’re currently dealing with A/C problems, check out the following helpful articles for some more A/C troubleshooting:

Is your car air conditioner ready for summer in Texas?

There you have it!   Now you know the answer to the question, “How does car air conditioning work?” If your follow-up question is “Why isn’t my A/C working?” However, that is another matter.

At Colony One Auto Center, we are happy to answer all your automotive maintenance questions and get you and your car safely back on the road as soon as possible. We know that summers in Texas are no joke and that a functioning A/C can mean the difference between showing up to work in a crisp, clean shirt or a soggy puddle of sweat. 

It’s time you beat the heat. Let us help you come up with an effective plan to get your A/C up and running (and running and running). Contact us online or call us at 281-800-9209.

Psst… ask us about our car repair warranty and what’s included in a tune-up!


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