Heating and Cooling Acronym Basics - Part 2

Maybe you fill like a kid in school again after reading Part 1 of Heating and Cooling Acronym Basics. What seems like a jumble of letters to the average person are part of the unique vocabulary used among heating and air service technicians and installers. The folks here at GAMA Air don’t want you and our other friends and neighbors in the Beverly Hills, Culver City, Mar Vista, Miracle Mile, Hollywood, West Hollywood, Los Angeles, West Los Angeles, Santa Monica, Marina Del Rey, Pacific Palisades, Brentwood, Bel Air, Westwood, Downtown Los Angeles, Vernon, Huntington Park, Sherman Oaks, Encino area to get nervous when you hear our guys and gals using these terms. So, let’s get back to the definition of some of the common acronyms in the HVAC industry.


The Energy Efficiency Ratio (EER) of a cooling unit is the ratio of the output of cooling energy measured in BTUs to the input of electrical energy measured in watt-hours at a given operating point. EER is generally calculated using a 95°F outside temperature, an inside temperature of 80°F and 50% relative humidity. The EER is a more realistic measurement of energy efficiency in warmer climates due to the high demand and higher cost of peak hour electricity. The higher the EER rating the better. Many regions now have minimum EER requirements on newly installed cooling systems.


This is the Heating Seasonal Performance Factor (HSPF) and is a measure of the efficiency of heat pumps when operating in heating mode. (Heat Pumps are also rated by SEER when operating in cooling mode.) HSPF is specifically used to measure the heating efficiency of air source heat pumps. HSPF is the heating output measured in BTUs during a typical heating season divided by the watt-hours of electricity used during the same period. The higher the HSPF rating of a unit, the more energy efficient it is.


The efficiency of air conditioners and heat pumps is often rated by the Seasonal Energy Efficiency Ratio (SEER). This acronym is an exception because It is pronounced as a word, rather than saying each letter like most of the other acronyms in this list. The SEER rating of a unit is the cooling output measured in BTUs during a typical cooling-season divided by the total electric energy input during the same period. The higher the unit’s SEER rating the more energy efficient it is. SEER rating more accurately reflects overall system efficiency on a seasonal basis whereas EER reflects the system’s energy efficiency at one specific operating condition. (See EER above, which is also most commonly pronounced as a word rather than individual letters.)


The Annual Fuel Utilization Efficiency (AFUE) is the most common measurement of the efficiency of fuel burning furnaces. This applies to furnaces that run on Natural Gas, Liquid Propane, and Fuel Oil. This measurement is one of the simplest to understand, since it is a percentage. If the AFUE rating on a furnace is 80%, then that means 80% of what you pay for fuel is being converted to heat, and the other 20% is lost. Clearly, the higher the number the better because it is a more efficient system that wastes less fuel. Why the waste? Burning fuel creates fumes that must be exhausted, and those fumes contain at least some of the heat from the burning. As of this writing there is no fuel burning furnace that is 100% efficient, although some manufacturers are making furnaces with an AFUE of 98% or so.

If you’re ready to get prices on the installation of a high-efficiency gas furnace system, either by itself, or along with an air conditioner, then give GAMA Air a call at (310) 651-6936. You can also use our online form to schedule a visit at a time convenient to you for a no-obligation quote. We guarantee your satisfaction 100%.

Need help with a question you have? Visit our Ask an Expert page and get a quick answer from the resident expert here at GAMA Air.

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