Seasonal Energy Efficiency Ratio - the higher the number = more energy efficiency of the unit

The efficiency ratio for a machine usually refers to the ratio of the useful energy available from a machine and the energy put into it.

efficiency
The ratio of useful energy to total input energy is called efficiency. It refers to the percentage of the work input that is converted to work output.

Engine efficiency is increased though compression ratio by allowing a more thermodynamic energy to be converted into mechanical energy. Energy transfer is the key to efficiency.

ratio of energy output to energy input.