The total energy input is the energy added to system to do useful work.
But we know according to the third law of thermodynamics that energy transfer is not efficient. Most of the energy added to a system is usually lost as heat.
There is no system that is 100% efficient
Most system uses a fraction of their energy intake to do work as useful energy
The remainder goes into heating the system and this is a waste energy
Any system that involves conversion of energy from one form to another is not 100% efficient and will lose heat as wasted energy
