what is a comparison of energy output with energy input
Energy conversion efficiency Energy conversion efficiency (Î·) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be chemical, electric power, mechanical work, light (radiation), or heat.[citation needed]
Seasonal energy efficiency ratio The SEER rating of a unit is the cooling output 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. In the U.S., the SEER is the ratio of cooling in British thermal unit (BTU) to the energy consumed in watt-hours. The coefficient of performance (COP), a more universal unit-less measure of efficiency, is discussed in the following section.