How does my air conditioner work

That is a good question. I think it is important every homeowner to understand how their system works. When the system is not working correctly you will have a better understanding of the diagnosis that your local service technician will give you when he is called. If you have an idea what he is talking about, you will have more confidence in him and his company that they know what they are doing. I do not know how many times I have heard stories about homeowners accusing technicians of trying to rip them off, only to find out that they were correct when a second company comes out and makes the same diagnosis. A majority of this can be avoided by understanding more about your system.

The basic refrigeration cycle:

Starting with the COMPRESSOR:

-The refrigerant (freon, R-22, etc.) enters the compressor as a low-pressure/low-temperature vapor. This is important since compressors are not very efficient at compressing liquids.

-The refrigerant is compressed causing the pressure and temperature of the refrigerant to raise significantly leaving the compressor as a high-pressure/high-temperature vapor.

-The compressor acts like a pump and moves the refrigerant through the system.


After leaving the compressor, the refrigerant enters the CONDENSER:

-The condenser is the set of coils outside that you can see with the fan usually blowing out of the top.

-The refrigerant enters the condenser as a high-pressure/high-temperature vapor.

-Once in the condensing coils, with the help of airflow from the fan, the refrigerant gives up some of its heat to the outside air causing the refrigerant to condense from a vapor to a liquid.

-The refrigerant is now a high-pressure/high-temperature liquid.


Whether you have a package unit or a split system, the refrigerant travels towards the TXV (Thermal Expansion Valve):

-Some systems might use either a small capillary tube or another metering device such as an orifice. Whatever the device, the process is still the same.

-The TXV or other metering device rapidly reduces the pressure of the refrigerant and by doing so, rapidly lowers its temperature as well.

-The refrigerant is now a low-pressure/low-temperature liquid.


After the metering device, the refrigerant enters the EVAPORATOR:

-Here the refrigerant absorbs heat from the air inside your house. (Heat always transfers from a high temperature substance to a low temperature substance).

-As the refrigerant temperature rises from the relatively hot air inside your house (moving by way of the fan), the refrigerant evaporates from a liquid back to a vapor.

-The refrigerant is again a low-pressure/low-temperature vapor and is ready to start the cycle over again as it travels back to the compressor.


This is the process in all vapor-compression refrigeration cycles, whether it is your freezer, refrigerator, or your air conditioner. If you still have any questions about the process feel free to send us an email and we will be glad to go into more details.