How Does AC Cool A Room?

Physicists will tell you that cold is merely the absence of heat. If you stand behind a refrigerator, you can feel the warm air coming out because the machine’s job is to remove heat, rather than add cold. Air conditioners work in a similar way.

When heat builds up in your Southern California home, an air conditioner takes that heat and sends it outside. While there are various types of air conditioning units, they all share similarities in the ways that they manage to take the warm air out and leave the inside delightfully cool and comfortable, even on a hot summer day.

Air Conditioner Components

All air conditioners use compressors, condensers, evaporators, and expansion valves to move warm air outside. In order to accomplish its task, the unit must have some access to the exterior of the home. Otherwise, the system would take all of the hot air from inside and circulate it back into your home.

A simple explanation is that the system uses a refrigerant to make part of the system cold. The refrigerant absorbs the heat in your house, which causes that refrigerant to become hot. Next, the system takes that heat and transfers it to the exterior of the home. The air conditioner then cycles around again, repeating the process to remove the warmth from a house continuously.

What is Refrigerant?

Refrigerants are chemicals. Freezers, refrigerators, and air conditioners all use these substances to remove heat from the air. Some chemicals that are used for this purpose include:


Modern systems do not use this chemical because of its environmental impact, although it was commonly used in the past.


This chemical can also be damaging to the environment but is less harmful to the ozone than chlorofluorocarbon. The United States is moving away from this chemical, as well.


Hydrofluorocarbons do not contain chlorine and are less harmful to the environment than the other options. Systems that use this type of refrigerant are more efficient and perform better than older air conditioning models.

Refrigerants in air conditioners run through copper coils. When the coils run through the warm inside air, they absorb the heat and the low-pressure gas condenses into a liquid. The system sends that liquid through outside coils, where the unit blows hot air to the home’s exterior. As the system dispels the heat outside, the chemical returns to its gaseous form and renters the home to absorb more heat.

A fan in the home pushes cooled air through rooms or through the ducts to circulate the air and lower the temperature. The process will repeat in a cycle until the home reaches the temperature that you set on your thermostat.

Air Conditioners Remove Humidity

Air conditioners also remove moisture from the warm air. The process that absorbs the warm air also leads to condensation. The system must then expel that moisture, as well. You may see a window air conditioning unit that drips outside. The water coming from these air conditioners is made from the humidity in the air inside the building.

Air Conditioner Care and Upkeep

Newer air conditioners use different refrigerants. Newer systems are also more efficient and can reduce energy costs. If your system is old, it may need maintenance, but it may also be time to replace that unit with something that will work better and cause less damage to the environment.

The technicians at Rowland Air can check your air conditioning system to ensure that it is running correctly, make repairs, or install a newer air conditioner model that will better serve your home. Give us a call today!