Air Conditioning Your Home: How it All Works

Compressor? Expansion valve? Evaporator coil? If you have no idea what these terms mean, you’re not alone. These are some of the important parts that make up your Phoenix heating and air conditioning system, which keeps you cool when it’s hot and warm when it’s not.

At Chas Roberts Air Conditioning & Plumbing, we don’t expect you to be well-versed in air conditioning terminology. That’s what we’re here for. If you’ve ever wondered how that very important home appliance works, we’re here to explain.

Here are some quick definitions:

  • Compressor: A very important part of the system, the compressor pumps refrigerant through all of the system’s components.
  • Expansion valve: As hot liquid refrigerant passes through this valve, it emerges as a cool low pressure mist that moves to the evaporator coil.
  • Evaporator coil: This cold coil cools off the air blowing across it and pushes it back into your home.

First, the Cool Side

When it comes to air conditioning, most Arizona homes have a central cooling system called a split system. This system has an outdoor condenser coil and compressor and an indoor evaporator coil. When the warm air inside your house blows across the indoor evaporator coil, the hot air transfers to the refrigerant that is pumped into the system by the compressor. It’s that transfer that cools the air inside your home. The heat that the refrigerant absorbs is pushed outside while cooled air is blown inside. It’s a cycle in which the refrigerant is pumped back to the compressor and the whole process starts over again.

Now, the Hot (or Warm) Side

Phoenix heating systems typically have a furnace, which consists of four main parts: burners that burn and deliver fuel, heat exchanger, a blower and a flue that acts as an exhaust.

Here’s how it all comes together. First, the burners generate combustion gases. Next, these gases are passed through the heat exchanger. Air inside the home blows across the heat exchanger to be warmed. Finally, the air is blown through a system of ducts that distribute it to the rooms in your house.

Here’s one final explanation, this time to a question we hear pretty often: Why is my Phoenix heating and air conditioning system all in one unit? The answer: The two are combined because they share the same ductwork for distributing air throughout your home. Have more questions? Or is your Phoenix heating and air conditioning system in need of repair? Set up an appointment today! Visit or call (602) 943-3426 in Phoenix or (520) 292-6858 in Tucson.