Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. How Does a Car's Air Conditioning Work?

How Does a Car's Air Conditioning Work?

ac how it works

All across North America, a climate change occurs every year. The cooler spring temperatures give way to warmer weather. In some areas this lasts for two months, and in others it lasts six months or longer. It’s called summer.

With summer comes heat. Heat can make your car unbearable to drive, which is why air conditioning was introduced by Packard in 1939. Beginning in luxury cars and now expanding into almost every vehicle produced, air conditioning has been cooling drivers and passengers for decades.

What Does Air Conditioning Do?

Air conditioning has two main purposes. It cools the air entering the passenger compartment. It also removes the moisture from the air so it feels more comfortable inside the vehicle.

In many makes, air conditioning cycles automatically when the defrost setting is chosen. It pulls the humidity from the windshield to improve your visibility. Often cold air is not required when the defrost setting is selected, which is why it is important to know that air conditioning functions even when the heat is selected on the heater control.

How Does It Work?

Air conditioning systems operate in much the same manner from manufacturer to manufacturer. All makes have some common components:

  • compressor
  • condenser
  • expansion valve or orifice tube
  • receiver/drier or accumulator
  • evaporator

The air conditioning system is pressurized by a gas known as refrigerant. Each vehicle specifies how much refrigerant is used to fill the system, and is usually three or four pounds at most in passenger vehicles.

The compressor does what it's name suggests, it compresses the refrigerant from a gaseous state into a fluid. the fluid is cycled through a refrigerant line. Because it is under high pressure, this is called the high side.

The next procedure occurs in the condenser. The refrigerant flows through a grid similar to a radiator. Air passes through the condenser and removes the heat from the refrigerant.

The refrigerant then moves on next to the expansion valve, or orifice tube. A valve or restriction in the tube reduces the pressure in the line and the refrigerant returns to a gaseous state.

Next, the refrigerant enters the receiver drier, or accumulator. Here, a desiccant in the receiver drier removes moisture that is carried in with the refrigerant in gas form.

After the receiver drier, the cooler, drier refrigerant passes into the evaporator, still in its gaseous form. The evaporator is the only part of the air conditioning system that is actually in the passenger compartment. Air is blown through the evaporator core, and the heat is removed from the air and transferred into the refrigerant, leaving cooler air exiting past the evaporator.

The refrigerant cycles through to the compressor again. The process continues repeatedly.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...


Related questions

Q: Air won't blow

This is a very common problem for your type of vehicle. Most likely what has happened is that the blower motor is going bad. As a result of that, it is drawing too much current. What is likely to be...

Q: My air is blowing cold-hot-cold-hot-cold-hot...

It is possible that you have a leak in the AC system. There are pressure switches that will turn off the compressor if the pressure is too high or too low. The low refrigerant level could cause the AC compressor...

Q: Air con isnt getting cold

Hello. You likely need to [pressurize the refrigerant]https://www.yourmechanic.com/services/heating-ac-inspection) in the system properly. Unfortunately there is no way to test the system without hooking up gauges and physically testing it. If you have recently filled the system, there may be a...