The ABC’s of HVAC: Understanding Industry Terms The heating and cooling industry is full of jargon and acronyms that can be confusing to homeowners. It’s like an alphabet soup of mysterious terms that make it harder to understand the operation of your HVAC system.

The ABC’s of HVAC: Understanding Industry Terms

The heating and cooling industry is full of jargon and acronyms that can be confusing to homeowners. It’s like an alphabet soup of mysterious terms that make it harder to understand the operation of your HVAC system. Let’s take some of that mystery away.

Here is a brief compendium of some commonly used terms and their meanings:

AC – stands for Air Conditioner or Air Conditioning. This one is pretty simple and well-known.

AFUE – or Annual Fuel Utilization Efficiency. This is the rating used to convey the efficiency of operation for gas furnaces. It is expressed as a percentage. The higher the percentage, the more efficient the furnace. The minimum government standard for AFUE in new furnaces is currently 80%.

BTU – or British Thermal Unit. The British thermal unit is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. In heating, it is a measurement of the heat being delivered into the home. In cooling mode, it measures the heat being removed from the home.

CFM – or Cubic Feet per Minute. This can be used as a measurement for the flow of a gas or to measure air velocity such as the air being pushed into a room from the vents in your floor or ceiling.

CO – Carbon Monoxide, a toxic gas that can be given off under certain conditions as a byproduct of combustion (such as with a gas furnace) and is called the “silent killer”. It can be difficult to detect and there are recommended monitors that can alert you if any is present.

EER – Energy Efficiency Ratio. The EER is a constant number that is used to measure the efficiency of certain types of systems such as geothermal. EER is typically determined by a set outside air temperature, a set inside air temperature, and a 50% relative humidity.

EPA – The United States Environmental Protection Agency is the federal office responsible for regulating anything impacting the environment. The heating and cooling industry works closely with the EPA in matters of safe handling of refrigerants used in systems including residential, industrial, and commercial applications. According to EPA regulations, in the United States, ozone-depleting substances (ODS) are regulated as controlled substances. Class II substances are all hydrochlorofluorocarbons (HCFCs). New production and import of most HCFCs will be phased out as of 2020. The most common HCFC in use today is HCFC-22 or R-22, a refrigerant still used in existing air conditioners and refrigeration equipment. 

ESA – This is our Energy Savings Agreement. Dirt and neglect are the leading causes of efficiency loss and early failure of heating and cooling equipment. Our ESA will ensure that the necessary regular cleaning and maintenance are properly performed. This agreement is a comprehensive full maintenance program that will help reduce costly repairs and maintain your heating and cooling equipment at its optimum performance level. Learn more

HVAC – or Heating, Ventilation, and Air Conditioning. This, of course, is the overall title that encompasses everything needed to deliver a full comfort system into your home. It is a catch-all term that includes equipment, ductwork, ventilation fans, and everything else needed to produce a comfortable indoor space.

PSI – or Pounds per Square Inch. The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress. It is the pressure resulting from a force of one pound-force applied to an area of one square inch. In our case, it’s generally used in reference to gas pressure levels.

SEER – This is Seasonal Energy Efficiency Ratio. The SEER measures air conditioning and heat pump cooling efficiency, which is calculated by the cooling output for a typical cooling season divided by the total electric energy input during the same time frame. The higher the SEER rating, the more efficiently the system operates. 

Ton – A ton in the HVAC universe is not actually a measure of weight. It is a unit of measurement equal to 12,000 BTU’s. This means that for every ton, an air conditioning system is rated to remove 12,000 BTU’s of heat from the home. 


If there is anything else that you would like to learn about the heating and cooling industry or have any questions in general regarding your home comfort system, the professionals of MSCO can help. Call 757-427-0016 anytime – we have been keeping you comfortable for over sixty years.

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Keeping our customers comfortable has been our mission since day one. As a family-owned, community-based heating, cooling, and AC company in Virginia Beach, the MSCO team is comprised of certified technicians, and Trane comfort specialists with decades of combined experience in the industry.

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