en'ergy effi"ciency ra"tio
a measure of the efficiency of a heating or cooling system, as a heat pump or air conditioner, equal to the ratio of the output in B.T.U./hour to the input in watts: A high-efficiency home window air conditioner has an energy efficiency ratio of 7.5 or more. Abbr.: EER
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.