HVAC Terminology

The most common Heating, Ventilation & Air Conditioning terms that home and business owners should be familiar with.

HVAC, like any other industry, is full of its own terminology, jargon, and abbreviations. It’s important to be at least somewhat familiar with the language to understand the ins and outs of your home heating and air conditioning system.

Knowing how to “talk the talk” will also help you communicate with your local HVAC repair provider and really understand what is going on with your system.

In this article, we want to talk about the most common terminology in the heating and air industry and what they mean.

HVAC Tools

Air Handler

Central heating and cooling systems have two main parts, the air handler, and the condenser. The air handler is located inside your home and contains all the components needed to heat, cool, and distribute air throughout the home. It looks like a big metal box.

BTU (British Thermal Unit) Heater


BTU stands for British Thermal Unit. This is a measurement that tells you how much heating capacity a piece of equipment has. One BTU is how much heat is necessary to make one pound of water one degree Fahrenheit hotter or colder.

The higher the BTU rating, the higher the heating or cooling capacity.

Capacitors are part of the electrical system


Capacitors are part of the electrical system of your HVAC. They are used to store the energy needed to start the compressor and motor and keep them running.

Condenser coil is located in the condenser unit


Your system has two coils, one in the indoor unit, and one in the outdoor unit. The one in your indoor unit is called the evaporator coil. The evaporator coil is responsible for cooling the hot air your system pulls from the rooms in your home. The metal coil holds the chilled refrigerant which absorbs the heat from the air as it passes over it.

The Condenser coil is located in the condenser unit outside the home and does the exact opposite of the evaporator coil. When the refrigerant in your evaporator coil absorbs the heat, it is sent to the outdoor condenser unit where it is released outdoors.

condensing unit sends liquid through HVAC units

Condensing Unit

The condensing unit is the part of the system located outside of the home. It is responsible for converting refrigerant from a gas to a liquid and sending it inside to be used to cool the air.

drain pan is to collect and drain water

Photo: Cool Change Heating & Air

Drain Pan

The drain pan is the plastic or metal pan located under your air handler. As a part of the heat transfer process, water is produced by your evaporator coils. The purpose of this pan is to collect and drain that water without damaging your home.

SEER stands for Seasonal Energy Efficiency Ratio

Photo: Vardell’s Air Conditioning

SEER Rating

SEER stands for Seasonal Energy Efficiency Ratio. It is the ratio of British Thermal Units (BTU) produced to the amount of energy consumed. Homeowners shopping for new systems should be familiar with SEER ratings to help them decide which system is best for their homes. HVAC equipment with a higher SEER is more efficient but costs more up front.

Final Thoughts

We hope you found these HVAC terms useful. The more familiar you are with HVAC terminology, the better prepared you are to make the right decision for your home.

When you have your system diagnosed by a technician, it’s essential to understand what is wrong with your unit and why before spending your money on parts and repairs.

Plus, a basic understanding of the most critical components and their role in operating the system will help you better maintain your unit and guide your future purchase decisions. Learn how to keep your bedroom cooler with these simple tips.

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Customer Reviews

best hvac company in Augusta
“I called 6 other companies when my AC stopped pushing air at 5PM. None of them seemed to want my business. When I got to Sig Cox, the guy who answered the phone was polite, knowledgeable, and was even trouble shooting with me before sending someone out. The agent got to my house in 30 minutes, troubleshoot, and fixed the problem in another 30. He even topped off the freon for free. The pricing was definitely agreeable. You’d get charged the same or more with any other company. Some of the best customer service I have seen. You should absolutely consider Sig Cox for you HVAC problems, I won’t be looking anywhere else.”
Nicholas Brennan
Nicholas BrennanGoogle Review
“These people are amazing. After hiring Sig Cox the first time to fix my HVAC unit about a year ago, I was more than happy, to say the least. Then about a week ago I had them install a new HVAC unit for me. This is by far the best a/c repair company in Augusta GA. They are professional, timely, and really take care of their customers. I highly recommend them and proudly give them an A+ rating! Thank you all so much!”
Chris Kirksey
Chris KirkseyGoogle Review
“This company did some work for my mother-in-law, of which she was quite pleased, so she recommended them to us. We had a downstairs unit that just wasn’t putting out any cool air. They came by post haste and assessed the unit, gratis. Of course it was a compressor failure so we had to make the hard decision to buy a new unit or fix what we had. The advice we got from our man on the scene was honest and sincere.
Since we had an older unit that used the phased out Freon and compressors are ugh, expensive, we went with a new unit. We decided on the Amana since it had a lifetime warranty on the compressor and rated well in Consumer Reports.
A month later the other unit failed and we replaced that as well. Six Cog worked with us on the price, we were never hassled on the payment, nor did they demand any payment on the spot and never did I feel pressured into anything. The install was smooth, fast and highly professional. Both units fired up, granted a month apart, and the house was cool almost immediately.
This company has a great reputation from what I can garner in the community, and I’m here to tell you that I recommend them highly as well. Please note that this is first recommendation I have ever put online.”
Donald Bradshaw
Donald BradshawGoogle Review
“Very good experience. The Service Technician, David, went above and beyond to assist us in our AC repair.”
Daniel Brown
Daniel BrownGoogle Review
“From the first time that Mr. Boarwright came out, I knew that your company was top of the line. None [of the other companies] laid it out on paper like Sig Cox.”
Steven Burris
Steven BurrisGoogle Review
“Thank you and your crew for your profession assistance in solving our unique heating and cooling situation that involved two seperate zones.”
PJ Rodgers
PJ RodgersGoogle Review
“It was a pleasure doing business with your staff. They were professional and provided the solution to our problem.
Margaret Brubaker
Margaret BrubakerGoogle Review
My air conditiong system went out, Sig Cox was recommended so I called them. Technician Andrew came out, was on time, and he properly diagnosed the problem. He had the part ordered. When the part came in, Nolan installed the part perfectly. Both technicians were very professional and knowledgeable. I even talked to the owner of the company who is involve day-to-day with his company. Very nice people to deal and they really go beyond what’s expected to help you get things fixed. I highly recommend Sig Cox!! Ask for Andrew or Nolan, they know what they’re doing!!
Dan Can
Dan CanGoogle Review
“We had a heating and air company we were satisfied with, but when we needed a new unit we went with Sig Cox because of the deal we couldn’t beat. We have been SO impressed with everyone we have worked with, from the customer service, to the salesman, to the technicians, they are all so friendly and professional! We will be loyal customers from now on!”
Ashley Marks
Ashley MarksGoogle Review