Confused Hvac Term
HVAC Terminology You Should Know

September 1, 2015

Like all professionals, HVAC industry experts often use acronyms and other forms of jargon. If you can speak their language, it will make conversations a lot easier. The HVAC terminology used in rating HVAC systems, in particular, will help you to make educated decisions about your air conditioning and heating needs.


HVAC units with high SEER (seasonal energy efficiency ratio) ratings perform more efficiently in all seasons. Experts determine the SEER rating by dividing the cooling output by the total energy input for that period. The minimum SEER allowed is 13 on appliances manufactured after January 23, 2006.


The AFUE (annual fuel utilization efficiency) rating measures the efficiency with which your combustion equipment consumes fuel over the heating season. This applies to your furnace, boiler and water heater. It is expressed as a percentage and tells you how many BTUs are used for heating for every 100 BTUs of natural gas provided or available during that particular period. The higher the AFUE, the more efficient the unit.


BTUs (British thermal units) communicate the amount of energy required to increase the temperature of one pound of water by one degree. You might also see BTU/h, which denotes the BTUs per hour, or mmBTU, which represents one million BTUs. BTUs are important in determining the size of the system needed for the space you wish to be cooled or heated. A larger room size requires more BTUs for efficient heating and cooling.

Your HVAC technician will often refer to your system’s heating or cooling capacity. This refers to its ability to heat and cool your home effectively and efficiently. HVAC professionals and manufacturers express cooling and heating capacity in BTUs.


The Integrated Energy Efficiency Ratio (IEER) measures the efficiency of cooling based on performance at various capacities for different levels of equipment operation. It is most commonly used in commercial applications.

For further information or to ensure you have the right system for your home, contact Ocean State Air Conditioning & Heating at (904) 574-5619. Understanding what is needed for your HVAC system can be overwhelming. The more you know about HVAC terminology, and the relevance of these terms, the better able you will be to make decisions that are right for your home and budget.

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