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Air Conditioning: A Crash Course

Air Conditioning: A Crash Course

Posted by
Ed Miller on Fri, May 20, 2016

inside an A/C unit

Sure, it was possible to live in Northeast Florida before the invention of home air conditioning units, but it was very uncomfortable. An A/C unit in Florida is like a furnace in colder areas: you don’t really want to live without them. If you own a home in the Jacksonville area, then you will want to understand the basics of how air conditioning works. This way you are educated if you ever have to purchase a new a/c unit or repair an existing one. So let’s look at what goes on inside that big magic box in the backyard.

The Basics

The basic principle is that when liquids evaporate and turn into gases, they absorb heat. Your A/C unit is basically a closed set of coiled pipes with special chemical refrigerants running through them. These refrigerants evaporate at room temperatures.

Cooling By Evaporation

The coils in the part of the unit inside your home are called evaporation coils. Ducts and fans force air inside your home over these coils. The refrigerants evaporate in the coils, cooling the air. This cooler air is blown back into your house creating a comfortable living environment for you and your family.

So inside your home, the refrigerant go from liquid to gas in the coils. The gaseous refrigerants flow through the coils to the box outside your home where they are converted back to a liquid in a process called condensation. This second set of coils outside your home is called condensation coils.

Closing the Loop with Condensation

The refrigerant chemicals in the coils evaporate naturally at room temperatures, but they need to be forced to condense back into a liquid. This is done by increasing the pressure of the gas in the coils. The machine that does this is called a compressor. Gasses at high pressures will condense back into liquids.

The compressed gas releases energy to the outside environment, cooling the refrigerant. This cool liquid refrigerant flows through the coils back inside your house into the evaporation part of the system. There is an expansion value at this point in the system to regulate the flow of liquid refrigerant into the evaporator coils.

Types of Units

Window air conditioners and units installed directly into the wall house both the evaporator and condensation coils in the same unit. In split A/C systems, the condenser coils and compressor are housed in a unit outside of the home. This reduces noise inside the home and increases the capacity of the entire system.

System Size and Efficiency

A/C units have a BTU rating for their capacity. BTU stands for a “British Thermal Unit” and represents the amount of heat necessary to increase the temperature of one pound of water by one degree Fahrenheit. A house that is 2,000 square feet might require a 60,000 BTU system. The EER of the system is the energy efficiency rating. This tells you how much energy in Watts the system will require. Systems with higher efficiency ratings often cost more, but the increased efficiency will result in reduced operating costs. So eventually the more expensive and efficient systems will pay for themselves.

Now that you know how an A/C unit works, you will understand what your HVAC contractor is doing when you install or repair your own unit. At Snyder, our expert professionals have served the Jacksonville area since 1970. We can help you put in a new A/C system, upgrade to a bigger or more efficient system or make repairs to an existing unit. Contact us for more information.


Air Conditioning Unit,

air conditioner,


cooling system,

AC Unit

where you’ll find snyder

Snyder Air Conditioning, Plumbing and Electric serves families across Florida. You'll find our technicians are just a short phone call away in neighborhoods throughout these counties:


  • Alachua
  • Baker
  • Clay
  • Duval
  • Flagler
  • Nassau
  • St. Johns


  • Broward
  • Martin
  • Miami-Dade
  • Palm Beach
  • St. Lucie

Customer Reviews

This was an exceptional experience! We woke up to our A/C on but not cooling (it was 6am and already 81 in the house). The person who set up our appointment was very nice, able to get us seen same-day, and let us know of some options to help save us money.

-Christy Cormier

The service from Sam and Chris was excellent! They were very knowledgeable and professional. They were able to answer all of my questions and completed all of my electrical issues. I will definitely use them again for future jobs. Thank you!

-Adrienne Beal

From the get go I could tell that the Snyder employees were truly professionals and didn’t push to make sales like other companies I’ve talked to my whole life. They took the time to explain so that I could make a decision. The installers and later the duct cleaners were very respectful during their work here. Thank you.

-Mike Daniels

Snyder Heating and AC is dependable, always on time and techs have always been courteous and knowledgeable. Emanuel was a great addition to the company. He was friendly and knew what he was doing. Thank you for great service.

-Linda Ackley

Snyder came in and did a total overhaul of our duct system. They had a great knowledge of what to do to make our home so comfortable! The technicians were all so professional and took great care of us! We’re so thankful for their expertise. Great and easy communication with the call center. We will definitely use them again!

-Crystal Hill

Snyder provided an amazing experience from start to finish. Most of us dread getting estimates with pressuring salespeople. Erik was a great guy, explained all my options and didn’t try to pressure me to act quickly! Justin followed up with my husband and I to offer further assistance in our decision. Again, no pressure, just helped with our follow up questions.

-Michele Bauer

Very prompt, professional, courteous, and cleaned up after repair. Had water line break in my front yard and no pressure. Very pleased and would highly recommend Snyder for all your plumbing, and AC needs. Thank you for making a rough morning get better with ease and professionalism.

-Chuck Jr.

Snyder was easy to get in contact with and had availability the next day. Clint came out and needed some parts so had to reschedule us for the next day for installation. He did a great job converting our old 3 knob shower to one. Looks great! Professional and courteous. 100% recommend this company, especially Clint.

-Nicole Hansen

Very thorough and professional Job

-John Ridenour

Excellent work. Hard worker. Highly recommend.

-Andre A

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