In this case, where energy output is the same as energy input, the output can be described as 100% or the system can be described as being 100% efficient. When efficiency is 100%, there are no energy losses in the form of heat, light, etc and the amount of energy input is equal to the amount of energy output.
A refrigerator is a system. The energy input into the refrigerator system (in the form of electricity) is the same as the amount of energy output from the system. Which of the following best describes the energy output of the system?