Air Conditioning Lingo Defined For The Rest Of Us

Air Conditioning Lingo Defined For The Rest Of Us Thursday, February 25, 2021

Have you been puzzled by terms such as SEER, MERV, or PAG? Air conditioning lingo can be a bit baffling when you hear it. However, understanding those terms, what they mean, and their importance isn’t solely for the professionals.

At True Plumbers & AC of Plant City, Lakeland, Winter Haven, FL and neighboring areas, we know that our average customers may not understand the lingo we use, and we want you to understand what we’re doing. Here are some of the basic terms and acronyms that we use all the time.

Air Conditioning Ratings and Measurements


SEER, or Seasonal Energy Efficiency Ratio, is the rating system used for central air conditioners. It indicates the unit's efficiency. You calculate it by taking the BTU per hour of cooling and dividing it by the input of electricity in watts. We average this over a cooling season to get the SEER rating.

MERV Rating

MERV stands for Minimum Efficiency Reporting Value. The MERV rating measures the efficiency of an air filter, specifically how effectively it removes dirt, dust, and other particles from the air as it passes through. The higher the MERV rating, the thicker the filter.


BTU stands for British Thermal Unit. This is how much heat it requires to raise the temperature of one pound of water by one degree Fahrenheit. The measure of heat extracted by your air conditioner is in BTUs.


CFM stands for cubic feet per minute. The standard measure of airflow, a typical air conditioning system requires 400 CFM per ton.


ACH stands for Air Changes per Hour, which is the measure of the air volume that gets added to or removed from a room during an hour, divided by the volume of the space. Simply put, the ACH is the measure of how many times the air gets replaced in an area every hour.

AC Parts and Power

Split System

A split system AC is an air conditioner with the condensing unit on the outside and the air handler and evaporator coil box on the inside. Both boxes connect with refrigerant lines. Your split system air conditioner may contain all or some of the following:

  • Return: The return is the side of the duct system that pulls air back into the air system to cool it again. You can easily find your return vent by holding a piece of tissue in front of it. If it pulls it toward the grate, it’s the return.
  • Ionizer: The ionizer is an additional filter that releases ions. These ions clean the air of microscopic matter, including dust and pollen, and diminish bad smells.
  • Louver: The louver assembly, composed of horizontal or vertical louver bands, is a decorative screening that hides the air conditioner's internal components from sight and helps protect internal mechanisms from damage.
  • PAG: PAG stands for Polyalkylene Glycol, which is a synthetic oil used in air conditioning systems for compressor lubrication. Most newer AC systems use PAG as their lubricant. The manufacturer of the AC system determines the viscosity of the PAG oil.


Freon is a coolant used in older air conditioners to help with evaporating the internal heat and expelling cool air. Freon is a chlorofluorocarbon (CFC) that manufacturers have phased out because of its link to adverse effects on the environment. At True Plumbers & AC, we know how to handle the collection and disposal of freon safely and completely.

Schedule an AC Consultation Today in Plant City, Lakeland, Winter Haven, and Surrounding Florida Areas —and Pick Up More AC Lingo!

With our years of experience in HVAC maintenance and repair, we at True Plumbers & AC not only have the know-how to get and keep your AC unit working, but we can tell you all about it, too. To learn more about our AC services or schedule a consultation in Plant City, Lakeland, Winter Haven, FL and surrounding areas, call us at (863) 667-6364.

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