How Many HVAC Acronyms Do You Know? Air Therm Helps You Out! LOL!

How Many HVAC Acronyms Do You Know? Air Therm Helps You Out! LOL!

Date - 02/24/2023

Chalkboard with diagram of TMAA: Tell Me About Acronyms

LOL, just for starters

We bet you know what LOL means, or that you’ve at least seen it sprinkled in text messages or email missives. (If you don’t know, LOL is an internet slang term that translates into “laughing out loud.”)

You might know that PS means “Postscript,” something you add on after you’ve written everything else.

DUI is Driving Under the Influence.

AWOL is Absent Without Leave.

BOGO is Buy One, Get One.

Americans love brevity and shortening words into letters is just what we do, making everything into an acronym.

The heating and air conditioning business is no different than the rest of the world. We shorten lots of phrases into acronyms. But sometimes, that makes a mush of meaning, an alphabet soup of letters where every spoonful is gibberish to people outside of the industry.

How many HVAC acronyms do you know? Let Air Therm help you out!

Here are six HVAC terms you need to know to understand your air conditioning and heating system.


This acronym sounds like something to do with eyesight, but in fact, it means nothing of the sort.

SEER means Season Energy Efficiency Ratio. Think of a SEER rating for your air conditioner as you would an MPG, Miles Per Gallon rating for your car.

Basically, a SEER rating tells you how much energy it will take for your system to bring your air to the requested temperature over an entire season.

In the early days of air conditioner manufacture, there was no SEER minimum rating, but in 1992 the government enforced a minimum of 10 SEER rating. Now, thirty years later, we have a clearer understanding of energy efficiency, and in 2023, the minimum SEER rating for air conditioners was raised to 15 for Southern states.

The higher the SEER rating on your equipment, the more energy efficient it will be, saving you money every month on your utility bills.


BTU is a measurement used throughout the world to gauge energy transfer in all kinds of appliances, furnaces, and air conditioners. It stands for British Thermal Unit.

Think of it as a way of measuring how much energy it takes for your air conditioner to pull heat out of the air. The BTU originally measured how much heat was needed to raise or lower one pound of water by one degree Fahrenheit, but the measurement was effective for determining energy transfer in all kinds of situations.

You need to match the BTUs of an air conditioning unit to the size of your home, so that you don’t spend more energy than you need to extracting the heat from the air around you.


Not a swerve or a curve or a nerve. Not good old Merv Griffin. Just MERV.

You know how we’re always talking about the importance of air filters and changing them frequently?

MERV is a rating for air filters. It stands for Minimum Efficiency Rating Value. You’ll keep your system in even better working order if when you change air filters, you use one with a high MERV rating.

In general, choose a filter with a MERV rating of 8 or more. A pleated filter has a MERV rating of 8, and anything above that is high efficiency and good quality for residences.

Surgery rooms, computer server spaces, and museums that are preserving artifacts choose filters with MERVs rating of 17-20.


While we’re talking about filters, we need to tell you about the impact of HEPA filters.

HEPA stands for High-Efficiency Particulate Air. Filters with a HEPA designation can trap even the tiniest particles of dust, dander, allergens, and smoke before they get into the air.

HEPA filters capture 99.97% of particles that are 0.3 microns.

How big is 0.3 microns?

A particle of 0.3 microns is

  • 1/25000 of an inch.
  • 1 millionth of a meter.
  • 1000 times smaller than the human eye can see.

HEPA filters improve the wellbeing of people with allergies, asthma, or respiratory ailments.


You may see the term CDD when you’re reading about air conditioners.

CDD is different than OCD (obsessive compulsive disorder) and CBD, the chemical found in marijuana.

CDD stands for Cooling Degree Days and is used in association with the weather. Cooling Degree Days calculate the number of days where the temperature reaches over 65 degrees Fahrenheit. The calculations incorporate the high and low temperatures of a 24-hour period. Combining these factors results in the number of Cooling Degree Days that occur in your area. A Cooling Degree Day implies that you’ll have to use air conditioning to stay comfortable.

Obviously, cool, Northern climates have many fewer Cooling Degree Days than the hotter Southern regions.

The more Cooling Degree Days you have, the higher your costs will be because you’re running the air conditioner more.

Studies show that over time, the number of Cooling Degree Days is increasing due to global warming. In 1970, the average summer temperature in Savannah was 80 degrees. In 2022, the average summer temperature in Savannah was 85 degrees with the thermometer on June 23 rising to 102. (Another good reason to join Air Therm’s Comfort Club to keep your air conditioner it tip-top shape with twice yearly tune-ups for every unit in your home. Just $99!)


Remember the old song lyrics, “All I need is the air that I breathe….”?

Nowadays, the air we breathe is not enough because it must be CLEAN air, free from contaminants that will hurt our lungs. Air pollution, smoke inhalation, and breathing in germs can make us sick.

IAQ stands for Indoor Air Quality, and it’s never been more important than it is now in our chemical-loving, polluted modern world just recovering from COVID.

Lucky for us, living in a modern world also gives us access to fantastic air filtration products like the REME HALO which is proven to eliminate 99.99% of COVID germs and other contaminants from the air. (If you want to talk about improving your indoor air quality, call us. Air Therm can help!)

The alphabet soup of HVAC acronyms is yours to savor, now.

Let Air Therm serve you up a delightful dish of knowledge about the best heating and air conditioning products for you and your family. We’ll make sense of the alphabet soup of HVAC acronyms for you!

Call us with questions or quotes.

We’ll treat you like our grandma.